Repairing Your Cracked Engine Block

#driveyourlife

cracked engine blockHaving a cracked engine block can feel like the end of your vehicle’s life.  Engine swaps can be extremely expensive and often not worth the investment in your current vehicle.  Also, having a cracked block is one of those extreme cases where it may not be possible to salvage your current engine.

There are many who have attempted to repair cracked blocks.  The main difficult is that you cannot simply weld an engine block since it is made from cast iron, not steel.  It is possible to weld cast iron using an arc welder and the proper welding rods, but that often can cause deformation to your engine block, or leave the welded area far more brittle and susceptible to further cracking.  The other common attempt at fixing a cracked block is called cold metal stitching.  This process is similar to sewing two pieces of fabric together, except it is far more difficult with metal.  The main difficulty with this process is that it does not work well on components that experience drastic temperature changes as the temperature change causes swelling and shrinking of the metal which will cause the metal stitching to tear and the crack to reopen.  This process is also often prohibitively expensive and only used on very large or expensive motors such as heavy equipment, diesel engines or marine motors.

There have been a variety of other attempts at sealing cracked engine blocks like using cold welding products, 2 part epoxies or a variety of other patches and fixes.  The problem in most cases is the same as with cold metal stitching in that the wide range of operating temperatures in your vehicle’s motor along with the thermal expansion of the metal cause most repairs to only last for a short time.

Before you attempt any repair on your cracked engine block, you want to be sure that is the problem you have.  If you have an external crack in your block that you can see, then the problem is easily identified.  If you have an internal crack the symptoms can often be similar to that of a blown head gasket.  To determine if you have a blown head gasket, you can read our article about the symptoms of a blown head gasket.Cracked Engine Block

The best way to seal a cracked block is to use BlueDevil Radiator and Block Sealer.  BlueDevil Radiator and Block Sealer is a specially formulated sealing agent that you add to your vehicle’s cooling system.  BlueDevil Radiator and Block Sealer can seal your cracked block from the inside out through your vehicle’s cooling system.  It is not a fibrous or particulate sealer that can harm or clog any other areas of your cooling system.  Instead, BlueDevil Radiator and Block Sealer has a special chemical formula that will bond to the metal in your engine block at the leak point until the leak is completely sealed.  The chemical weld formed by BlueDevil Radiator and Block Sealer will create a permanent seal that can expand and contract with the temperature changes in your engine.  Since there is nothing harmful in BlueDevil Radiator and Block Sealer it can stay in your cooling system indefinitely sealing any future leaks your may have in your vehicle’s radiator or engine block.

00205_blocksealer

BlueDevil Radiator and Block sealer works so well, it comes with a guarantee of performance.  If you purchase it from BlueDevil or one of our partnering local auto parts stores we guarantee a permanent repair!

Since you’ve got nothing to lose, pick up BlueDevil Radiator and Block Sealer today!  You can purchase it directly from BlueDevil here.

Pictures provided by:

Cracked Block – By Nick Ares – Licensed by Creative Commons Share Alike 3.0 Via Flikr – Original Link

275 responses to "Repairing Your Cracked Engine Block"

275 Comments

  1. LEE on January 23, 2015 at 5:17 pm

    I used Blue Devil, on an 84 Buick 5.7 Diesel Engine that had either a cracked block or a blown head gasket, and it worked very well. Sealed the leak successfully and was very happy with the product. Company Technicians were very helpful and very interested in solving my problem. Wished I still had that vehicle, as it was an Estate Wagon, pretty rare with the Diesel engine !!

    • Duwaine hale on April 6, 2017 at 8:48 pm

      I got a crack head on buick will it help

      • BlueDevil Pro on April 7, 2017 at 9:01 am

        Duwaine-

        Yes, we recommend applying BlueDevil Head Gasket Sealer (http://store.gobdp.com/head-gasket-sealer-38386/) to seal the cracked head.

        Thank you!

        -BDP

        • ron marchand on November 3, 2022 at 7:52 pm

          I have put 2 bottles in my 5.9 Cummins, leaking outside from a cracked block. it leaks only when driving. it still leaks. do I need to add more?

          • BlueDevil Pro on November 4, 2022 at 8:17 am

            Ron-

            How large or how much water capacity does the cooling system hold? What product did you use? Please contact our technical support line at 888-863-0426 so that we can get a little better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

            Thank you!

            -BDP



      • BlueDevil Pro on April 7, 2017 at 9:06 am

        Duwaine-

        Please contact our technical support line at 888-863-0426 so that we can get a better understanding of your Buick’s condition and be able to make any appropriate recommendations.

        Thank you!

        -BDP

    • Mildred Terrell on April 15, 2017 at 4:19 pm

      I have a crack in my engine will product work my truck

      • BlueDevil Pro on April 17, 2017 at 10:15 am

        Mildred-

        As long as the vehicle will maintain idle for a full 45 minutes, without overheating or stalling out, and you are not losing more than about a quart of water/coolant during that 45 minutes, you would be a great candidate for the BlueDevil Radiator & Block Sealer (http://store.gobdp.com/radiator-block-sealer-00205/).

        Thank you!

        -BDP

        • Anthony Cantu on December 29, 2022 at 7:54 pm

          Would I have to put a water hose in the radiator to make sure there is water in the cooling system? I have a 81 El Camino with a cracked block… no water in the oil…

          • BlueDevil Pro on January 3, 2023 at 9:27 am

            Anthony-

            Yes, you would want to have either water or antifreeze in the system when applying BlueDevil.



      • Evah on May 26, 2019 at 10:41 am

        My car has a cracked block so where can I get the blue devil products

        • BlueDevil Pro on May 28, 2019 at 10:04 am

          Evah-

          Where are you located? Please contact our technical support line at 888-863-0426 for further assistance.

          Thank you!

          -BDP

    • Chris on June 18, 2017 at 11:12 am

      How about on a 3.0 mercrusier

      • BlueDevil Pro on June 19, 2017 at 9:33 am

        Chris-

        Yes, the BlueDevil Radiator & Block Sealer is safe and compatible to use on your 3.0 Mercruiser. Feel free to contact our technical support line at 888-863-0426 with any other questions.

        Thank you!

        -BDP

        • Jason on May 8, 2018 at 3:49 pm

          How do I run this in an inboard boat engine

          • BlueDevil Pro on May 9, 2018 at 8:34 am

            Jason-

            The key of the BlueDevil working is that you are able to circulate the same body of water for the recommended 50 minute idle; on a marine engine you could use a bucket or barrel to accomplish this. The other necessity is that the water will heat to at least 150 degrees during that run. Feel free to contact our technical support line at 888-863-0426 with any other questions.

            Thank you!

            -BDP



        • Terry on April 4, 2019 at 7:21 pm

          Yes I have a 2000 Cadillac DTS 4.6 v8 and my oil and water is mixing and leaking from the bottom of the car. That means cracked head? Will this product work?

          • BlueDevil Pro on April 5, 2019 at 10:22 am

            Terry-

            Thank you for asking about your Cadillac DTS. Are you getting water/coolant back into the engine oil or oil into the radiator? Please contact our technical support line at 888-863-0426 so that we can get a little better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

            Thank you!

            -BDP



      • Jaedon on April 16, 2018 at 10:47 am

        If it causes further damage to my engine will I be compensated was told this was my only route and cheapest to fix my head gasket issue 1986 Dodge W250 Mopar 360

        • BlueDevil Pro on April 16, 2018 at 12:35 pm

          Jaedon-

          The BlueDevil Head Gasket Sealer does not contain any solid or particulate matter, so it is a non clogging product. It would not cause any further damage to an engine. Feel free to contact our technical support line at 888-863-0426 with any other questions.

          Thank you!

          -BDP

          • Dillan Musonda on August 13, 2018 at 12:53 am

            Can the cracks on top of the engine block be sealed with blue devil?



          • BlueDevil Pro on August 14, 2018 at 8:45 am

            Dillan-

            Yes, BlueDevil will seal engine block cracks. As long as you are not losing water/coolant too quickly, the vehicle would be a good candidate for the product. Feel free to contact our technical support line at 888-863-0426 with any other questions.

            Thank you!

            -BDP



          • Tony on July 22, 2021 at 1:44 am

            F 250 larait 2008 6.4 super diesel, they said cracked block, truck runs. Poured water in reservoir comes out of oil drain plug. Will blue devil help.



          • BlueDevil Pro on July 22, 2021 at 8:46 am

            Tony-

            Thank you for asking about your Ford F-250. Based on your description, it sounds as though you are losing water just as quickly as you add it. If that is the case, the leak would be larger than what the BlueDevil Head Gasket Sealer is intended for. A hard part repair may be your best option.

            Thank you!

            -BDP



          • Dan on December 22, 2022 at 7:45 pm

            Hello I have an old welding machine and I’m getting oil in my cooling system. Oil pressure is higher than cooling system pressure so will you product seal the crack and stop the oil from entering my cooling system?



          • BlueDevil Pro on January 3, 2023 at 9:06 am

            Dan-

            Unfortunately, we do not manufacture a product intended to stop oil from getting into the cooling system. A hard part repair may be your best option.

            Thank you!

            -BDP



      • Rick on July 12, 2018 at 9:03 pm

        Have you tried this yet Jason or Chris I have same problem. Could heat up metal barrel with propane torch or hot plate maybe ?. Then recirculate exhaust water with small pump back to intake tank.

    • Edith Jackson on March 1, 2018 at 11:37 am

      Is the dealership says that I have a crack in my ceiling and wall the 2016 Chevrolet Malibu can it be fixed or do I need another engine

      • BlueDevil Pro on March 1, 2018 at 2:35 pm

        Edith-

        Thank you for asking about your Chevrolet Malibu. Are you saying that there is a crack in the heads and the block? Please contact our technical support line at 888-863-0426 so that we can get a better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

        Thank you!

        -BDP

        • Sabelo on January 15, 2022 at 12:12 am

          Hie i used this on my ford fiesta now it is continuously overheating. I don’t know what to do now

          • BlueDevil Pro on January 17, 2022 at 9:12 am

            Sabelo-

            Thank you for asking about your Ford Fiesta. Please contact our technical support line at 888-863-0426 so that we can get a little better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

            Thank you!

            -BDP



    • Patrick Lawe on August 1, 2018 at 10:34 am

      Hi. I drive a 2003 Honda Civic. It has been reconditioned @ cost of $12,000 CA. Now I have been told there’s an internal crack in the engine block (by crank sensor). How can Blue Devil’s Radiator & Block Sealer work through the rad to fix an area where oil drips from? And I’m very concerned about what particles may be running through the system. You guarantee there will be no damage. Sure?

      • BlueDevil Pro on August 2, 2018 at 8:47 am

        Patrick-

        Thank you for asking about your Honda Civic. Unfortunately, we do not manufacture a product intended to stop oil dripping from the block. The BlueDevil Radiator & Block Sealer is only intend for water/coolant leaks, specifically, an external seep or a light drip coming from the radiator or block. Based on your description, a hard part repair may be your best option.

        Thank you!

        -BDP

    • Hasting on October 26, 2018 at 4:38 am

      I think my block is cracked. I have oil in my radiator with the water. Its leaking from the block. The block has no oil or water. Will I need to flush the oil/water out before I add this or while it is in then flush.

      • BlueDevil Pro on October 26, 2018 at 8:59 am

        Hasting-

        Unfortunately, we do not manufacture a product intended to stop oil from getting into the radiator. BlueDevil Radiator & Block Sealer is only intended for water/coolant leaks. Based on your description, a hard part repair may be your best option.

        Thank you!

        -BDP

    • Angela on April 28, 2019 at 6:55 am

      I have a 03 caravan, has blown/cracked head, blows white smoke and water from tailpipe, is it worth a shot to go buy some, will it seal it?

      • BlueDevil Pro on April 29, 2019 at 9:19 am

        Angela-

        Thank you for asking about your Caravan. As long as the vehicle can maintain idle for a full 50 minutes, without overheating or stalling out, and you are not losing more than about a quart of water/coolant during that 50 minute run, you would be a good candidate for the product. Feel free to contact our technical support line at 888-863-0426 with any other questions.

        Thank you!

        -BDP

    • Jon Jones on July 4, 2021 at 8:11 pm

      How exactly did you pour it? And how long wait?? And did it help for a while?
      My # is 8127092219

    • Frenk on July 28, 2021 at 3:00 am

      Hi I have 3s engine but block is have crak some place so it’s making me to use more engine oil than normal, can I find it and I will work, and how to use it I’m from Tanzania

      • BlueDevil Pro on July 28, 2021 at 8:18 am

        Frenk-

        The product we manufacture for oil leaks, BlueDevil Oil Stop Leak, is only intended for rubber seals/gaskets. Unfortunately, it would not have any effect on a metal component. Having the block replaced may be your best option.

        Thank you!

        -BDP

    • Raresapphires on August 6, 2021 at 11:29 pm

      Would this work on a GMC Bus that has a cracked block just below the manifold

      • BlueDevil Pro on August 9, 2021 at 8:22 am

        Raresapphires-

        Yes, the BlueDevil Head Gasket Sealer is safe and compatible to use on your GMC Bus. Be sure to follow the cooling system capacity table on the back of the bottle to ensure the proper amount of product is used. Feel free to contact our technical support line at 888-863-0426 with any other questions.

        Thank you!

        -BDP

  2. Dave Andrson on March 26, 2015 at 2:42 pm

    Do you have some customers that have been successful with sealing a engine block that I could talk to? I have a straight six that has a crack, I would like to repair.

    • BlueDevil Pro on March 26, 2015 at 2:50 pm

      Dave-

      We have had multiple reports of the BlueDevil Radiator & Block Sealer successfully sealing a cracked/leaking engine block. We would be happy to discuss the product with & can be reached directly at 888-863-0426. We are available from 8:00 AM – 5:00 PM, Monday – Friday.

      Thank You!

      -BDP

      • Agustin boria on November 5, 2016 at 8:36 pm

        I have a 2007 odyssey with 148,000 miles it s been giving me multiples misfire took it to a specialist and they yold me that cylinder 5 is low presure it evaporates my coolant and its smells like coolant wen is warm they said i need to replace the motor it will be spencive

        • BlueDevil Pro on November 7, 2016 at 4:06 pm

          Agustin-

          Thank you for asking about your Honda Oddyssey. It is also possible that you are getting combustion/exhaust gases pumping back into the cooling system.  You can use a “Block Dye Tester” to confirm whether or not that is the case.
          BlueDevil Head Gasket Sealer will still work if your vehicle is getting combustion/exhaust gases blowing into the cooling system and creating pressure.  To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with the low compression reading.  If you are not sure which one that is, you may pull all of the spark plugs and will notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull.  Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly.  Be sure to follow the guidelines for the proper amount to use based on the size of your cooling system.

          Thank you!

          -BDP

      • Joe on December 21, 2021 at 12:08 am

        I have a ’85 Chevy s10 with a 2.8 l. It has a crack on the outside of the block and inside. Will this work to fix the crack so I don’t have to replace the block?.

        • BlueDevil Pro on December 21, 2021 at 8:25 am

          Joe-

          Thank you for asking about your Chevy S-10. How quickly are you losing coolant? Is the vehicle overheating or are you having any other symptoms? Please contact our technical support line at 888-863-0426 so that we can get a little better understanding of the vehicle’s condition and be able to make any appropriate recommendations.

          Thank you!

          -BDP

    • J.S on December 3, 2017 at 2:04 am

      I have a Caterpillar C13 Peterbilt it’s leaking and I have done the head and gasket and had all attached components press tested but it still leaks and I don’t know where will Blue Devil work on a caterpillar engine or is it to much pressure

    • Jon Jones on July 4, 2021 at 8:12 pm

      Did you ever get the crack fixed?

  3. scott t on March 28, 2015 at 6:43 pm

    what about using it on a marine engine?

    • BlueDevil Pro on March 30, 2015 at 9:59 am

      Scott-

      Yes, the BlueDevil Head Gasket Sealer can be used in marine engines. The marine engine must be inboard for BlueDevil to work properly due to the fact that you need the same water to circulate for 50 minutes.

      Thank You!

      -BDP

      • Jonathan on June 11, 2015 at 7:21 pm

        Can it be used on an inboard/outboard by increasing the concentration of the product and recirculating using a tub to provide cooling water and catch the exhausted water?

        • BlueDevil Pro on June 12, 2015 at 2:18 pm

          Jonathan-

          As long as you are able to use a barrel/bucket to circulate the same water for the 50 minute idle. The main components you need are a combination of heat (at least 150 degrees) and circulation.

          Thank You!

          -BDP

        • Mac on July 3, 2015 at 1:35 pm

          Jonathon,

          How did it work for you on your marine engine?
          When recycling the same water, did you have temperature issues?

          I am in same boat, so to speak. I have an internal block crack that is g
          letting water into oil. I am trying to avoid replacing the engine.

          I look forward to your reply
          Mac

          • Troy on October 10, 2016 at 8:10 am

            I may habe the same issue and thinking of giving thos a shot. Anyone have success?



          • BlueDevil Pro on October 11, 2016 at 1:43 pm

            Troy-

            Feel free to contact our technical support line at 888-863-0426 if you have any questions or concerns.

            Thank you!

            -BDP



      • David wilson on March 15, 2022 at 5:18 pm

        Had a leak on a 86 corvette 5.7 used half gallon of antifreeze every 30 miles or so did not leak into oil or exhaust could not find leak did pressure test held pressure for long time then slowly would drop couple pounds so i bought 2 bottles of pour and go and it slowed leak way down now i can drive a couple weeks and only lose 20 ounces sometimes so I put the pressure test back on it got underneath of it and was looking I’m looking from the top and right where the crank pulley is somebody that I bought the car from before and put some kind of silicone or something there so I guess the block is cracked there but Blue Devil head gasket sealer fill dirt from the inside and now it only leaks a little bit so I’m very satisfied with the product but I’m wondering if I should put block sealer in there and maybe that will fix it from the inside to where it won’t leak at all

        • BlueDevil Pro on March 16, 2022 at 8:35 am

          David-

          If you noticed improvement after the first application, a second application may be recommended. Please contact our technical support line at 888-863-0426 for further assistance.

          Thank you!

          -BDP

  4. Martin on April 5, 2015 at 12:13 am

    Can the radiator and block sealer be used on a marine engine? I think I have an internal Crack inside the block due to poor winterization.

    • BlueDevil Pro on April 6, 2015 at 12:30 pm

      Martin-

      Yes, the BlueDevil Radiator & Block Sealer can be used on marine engines; it must be an inboard motor.

      Thank You!

      -BDP

      • Martin on April 6, 2015 at 5:03 pm

        It is an inboard. 454 big block. Is there a mixture ratio that I need to follow. Since I will be circulating the same water out of a tank through the cooling system I wasn’t sure how many bottles I would need.

        • BlueDevil Pro on April 7, 2015 at 9:35 am

          Martin-

          Please contact us directly at 888-863-0426 and we will be happy to get a capacity chart to you or discuss it with you over the phone. If you purchase the 32 ounce BlueDevil Head Gasket Sealer, it does come with a capacity table printed on the bottle.

          Thank You!

          -BDP

          • Bart on February 14, 2017 at 1:15 pm

            I have a 110 Outboard that has water in the #4 Cylinder. Is this a product that I can use?



          • BlueDevil Pro on February 14, 2017 at 1:39 pm

            Bart-

            The BlueDevil Radiator & Block Sealer can only be used in outboard motors if you are able to circulate the same water for the 45 minute run; using a 5 gallon bucket would accomplish this.  The other need is that the water will heat to at least 150 degrees F. during that run. Feel free to contact our technical support line at 888-863-0426 with any other questions.

            Thank you!

            -BDP



      • Larry on September 18, 2016 at 7:02 pm

        I used bars stop leak for a blown head gasket or cracked cylinder head. It fixed the water coming out of tail pipe and there is no water in the oil. However the car is losing compression and has a miss. Do you think this is a cracked cylinder and do you think your product can fix this ??

        • BD Auto Pro on September 28, 2016 at 6:12 pm

          Larry,

          Thanks for your question about your leak. Even if you do not have coolant in the oil or out of the exhaust you may still have a small coolant leak either from a blown head gasket or a cracked cylinder head. If you had water in your oil you could be losing compression due to corrosion of the cylinder walls or cylinder rings as well as a crack in your head, block or a partially blown head gasket. Unfortunately, to confirm any of these things you would have to tear down your engine to check.

          Thanks again for your question!
          -BD Auto Pro

      • William on October 26, 2016 at 8:53 pm

        Do yall make something for a desiel

        • BlueDevil Pro on October 27, 2016 at 8:27 am

          William-

          Yes, the BlueDevil Head Gasket Sealer would work on diesel as well as gasoline engines. Feel free to contact our technical support line at 888-863-0426 with any other questions.

          Thank you!

          -BDP

  5. Matt L. on April 19, 2015 at 8:38 pm

    What does the guarantee cover? I have a cracked block for sure. It is located right under the intake manifold where the lifters are on a 350 sbc. It is allowing coolant to mix with my oil. I’ll have to buy upper gasket set if I use this block including new head gaskets. Will the guarantee cover all my part costs? The labor I do myself.

    • BlueDevil Pro on April 20, 2015 at 11:12 am

      Matt-

      The product carries a money back guarantee. If the product does not work we will reimburse the purchase price of the BlueDevil product purchased.

      Thank You!

      -BDP

  6. Jim on May 6, 2015 at 12:11 pm

    is there a sealer you can use in the oil of an air cooled enging (lawn mower)

    • BlueDevil Pro on May 15, 2015 at 2:14 pm

      Jim-

      Unfortunately, we do not manufacture any products that are meant for the type of problem you have described.

      Thank You!

      -BDP

  7. nick on June 2, 2015 at 6:50 pm

    will blue devil work in 2stroke engines?

    • BlueDevil Pro on June 4, 2015 at 2:19 pm

      Nick-

      Yes, it will work in a 2 stroke engine. Be sure to follow the capacity chart as you will not need a whole lot to treat a cooling system of that size.

      Feel free to contact us at 888-863-0426 with any questions.

      Thank You!

      -BDP

      • Maddness on August 9, 2016 at 10:50 pm

        Can this product seal an engine with a hole?

        • BlueDevil Pro on August 10, 2016 at 3:09 pm

          Maddness-

          As long as the vehicle will not lose more than about 1 quart of water during a 45 minute idle then there is a very good chance the BlueDevil Radiator & Block Sealer will be able to seal it. If you are losing more than that then your vehicle will require a hard part repair.

          Thank you!

          -BDP

  8. Erika on June 22, 2015 at 3:16 pm

    I was wondering that if you use the blue devil and it seals it,does it allow you to drive far distances without it messing up again or no?

    • BlueDevil Pro on June 23, 2015 at 11:45 am

      Erika-

      Once BlueDevil creates a seal it is permanent. There is no restriction on speed or distance; neither would affect the quality of the seal.

      Thanks!

      -BDP

  9. william Thames on June 23, 2015 at 12:00 am

    I have an 89 dodge caravan with two small cracks in the block no bigger than a penny, would this product work and should i try sealing it from the outside as well?

    • BlueDevil Pro on June 23, 2015 at 10:59 am

      William-

      You should have no problem sealing a leak of that size with the BlueDevil Radiator & Block Sealer.

      Thank You!

      -BDP

      • johnetta on September 29, 2015 at 10:13 am

        Hello i have a 2000 Chrysler van and I have an engine block late will it help Cell that up the leak i used jD wheeler an it dent help because of the heat ….dose this product works against heat?

        • BlueDevil Pro on September 30, 2015 at 12:15 pm

          Johnetta-

          Yes, the BlueDevil Radiator and Block Sealer would be able to help seal the leak in your Chrysler. The product is attracted to airflow. once it is introduced to the system, it will look for the temperature differentials in the system and react with heat to form a chemical weld. Feel free to contact our technical support line at 888-863-0426 with any other questions.

          Thank you!

          -BDP

  10. Jim on July 6, 2015 at 6:27 pm

    Hi I have twin Mercruisers I/O’s with GM 305’s on my boat with cracked blocks on the inboard side of each block. It is a fresh water boat, however there is rust residue coming from the cracked areas (which we would expect).
    1) Will the rust reside affect your products ability to seal?
    2) Do you have any solutions for circulating your product on mercruiser I/O Stern Drives ?

    Thanks

    • BlueDevil Pro on July 10, 2015 at 10:20 am

      Jim-

      Yes, the rust residue could potentially affect the BlueDevil’s ability to seal.

      We have had customers use the product in marine engines by circulating the same water in a barrel or bucket. The main components you will need are circulation of the same body of water (3 – 4 gallons preferably) and heat.

      Feel free to contact our tech support team at 888-863-0426 with any further questions.

      Thank You!

      -BSP

      • David on June 3, 2017 at 7:17 pm

        I don’t know if my block is cracked are the head gaskets are bad but what product do I use because I don’t have a radiator it’s water cooled

        • BlueDevil Pro on June 5, 2017 at 9:59 am

          David-

          Based on your description, we recommend using the BlueDevil Head Gasket Sealer (http://store.gobdp.com/head-gasket-sealer-38386/). The product would treat blown head gaskets as well as a crack in the block. Does the system use a water pump to circulate water? Feel free to contact our technical support line at 888-863-0426 with any other questions.

          Thank you!

          -BDP

    • Rob on August 9, 2015 at 11:50 pm

      Hi Jim I also have an I/O with a cracked block just wondering if you have tried to seal it and how it worked? Thanks

  11. JD on July 6, 2015 at 7:39 pm

    my car was always over heating.. I thought it was the water pump cause water was leaking out of the bottom. We replaced that and the thermostat. We took it for a ride it it lose power, shared and heVy white smoke and water came out the exhaust… We were told it’s a blown head gasket. We bought the blue devil. Took it for a drive again, the smoke & shaking went away.. But it still over heats. I don’t know what else is wrong.

  12. Chris on July 9, 2015 at 2:56 pm

    If I use this product for en exterior cracked block will this prevent me from doing any future work to the motor? Someone told me after using this they were unable to remove the head without harming the head itself. It’s a 1952.

    • BlueDevil Pro on July 10, 2015 at 10:22 am

      Chris-

      Use of the BlueDevil product would not change the difficulty of making any future repairs. The product is attracted to airflow and reacts to temperature differential to create a chemical weld; therefore the seal created by BlueDevil will only show up at the point of any leak.

      Thanks!

      -BDP

  13. Pam Harvey on July 13, 2015 at 4:50 pm

    If my radiator leaks and is empty, do I need to pour some water in before pouring the product to keep the product from leaking out?

    • BlueDevil Pro on July 15, 2015 at 8:30 am

      Pam-

      Yes, the cooling system should be basically full just leaving enough room for the recommended amount of BlueDevil.

      Thank You!

      -BDP

      • kenny on July 16, 2015 at 9:46 pm

        Do I need to drain all antifreeze before using blue devil

        • BlueDevil Pro on July 17, 2015 at 8:35 am

          Kenny-

          Yes, you should flush the cooling system and refill it with water.

          Thanks!

          -BDP

          • echo on July 25, 2015 at 11:19 am

            Will blue devil seal a crack in a 305 inboard/outboard about 4 to 5 inches long if we circulate the same water or is that too long of a crack?



          • BlueDevil Pro on August 4, 2015 at 10:37 am

            Echo-

            It really depends how quickly you are losing coolant. In general, BlueDevil will have a great shot at working as long as you will not lose more than about 1 quart of water during a 50 minute idle.

            You will definitely want to circulate the same water if you decide to use BlueDevil to ensure proper results. Feel free to contact our tech support team at 888-863-0426 with any questions.

            Thank You!

            -BDP



  14. Mark Dressel on August 5, 2015 at 2:45 am

    My 1995 Nissan van is leaking oil and coolant from a crack in the block will blue devil fix this problem?

    • BlueDevil Pro on August 5, 2015 at 9:50 am

      Mark-

      Unfortunately, we do not manufacture any products that are intended for an oil leak from the block. The BlueDevil Oil Stop Leak is intended specifically for rubber seals and gaskets and the Head Gasket Sealer is designed to stop coolant loss. Feel free to contact us at 888-863-0426 with any other questions.

      Thank you!

      -BDP

  15. Jeanne on August 28, 2015 at 4:27 pm

    Can I use this on my 1987 VW Vanagon Air-cooled engine with an internal cracked head?

    • BlueDevil Pro on September 3, 2015 at 2:45 pm

      Jeanne-

      Yes, you can safely use the BlueDevil Head Gasket Sealer in your 1987 Vanagon. Feel free to contact us at 888-863-0426 with any questions or for further instruction.

      Thanks!

      -BDP

      • Geoffrey Sutton on February 27, 2021 at 6:14 pm

        I have to add that he stated it was an air cooled vw. No cooling system

  16. Tom on September 6, 2015 at 2:07 pm

    I have a1930 model a with 2″ hairline crack in the blocks exterior . My concern is will this clog my radiator. A friend used bars and it clogged his radiator . Model a engines are an open system not under pressure . Would that make a differance ?

    • BlueDevil Pro on September 23, 2015 at 4:41 pm

      Tom,

      Thanks for your question about your Model A. The low pressure of an open system won’t make a difference as it is the temperature differential at the leak that activates BlueDevil Radiator and Block Sealer. Similarly, BlueDevil Radiator and Block Sealer won’t clog your radiator as the temperature differentials there aren’t great enough to activate the sealing agent.

      Thanks for your question!
      -BD Auto Pro

  17. Earl L. Forman,II on September 6, 2015 at 7:55 pm

    I have a 2002 Honda Accord with a 3.0 engine.
    The problem is a porous block leak.Which of your products would you recommend ?

  18. Angel on September 7, 2015 at 10:36 pm

    My 1996 nissan maxima leaks oil and I dont know from where but it’s a pretty bad leak I used blue devil as instructed left it running for 50 minutes with the heater full blast it didn’t really slow the leak is there a reason why and if it doesn’t stop the leak do I still get my money back guarantee

    • BlueDevil Pro on September 8, 2015 at 10:37 am

      Angel-

      The BlueDevil Head Gasket Sealer is only intended for coolant/water leaks. Unfortunately, we do not manufacture a product intended to stop oil leaks from the block or head gasket. Please contact our technical support at 888-863-0426 to assist you for the warranty on the product.

      Thank you!

      -BDP

  19. mike on September 16, 2015 at 11:13 pm

    I have a small leak on a 1999 2 stroke motorcycle I hit something on bottom of motor and chipped a piece of the metal off just a small oil leak the problem is though it is air cooled. What might you suggest. Thanks mike

    • BlueDevil Pro on September 17, 2015 at 9:21 am

      Mike-

      Unfortunately, we do not manufacture any product that will seal a leak that is due to damage. Our BlueDevil Oil Stop Leak is specifically designed to rejuvenate and recondition the rubber seals/gaskets.

      The only solution may be to have the part replaced.

      Thank you!

      -BDP

    • Lewis Walkeryahoo on June 30, 2016 at 4:29 am

      I have just water coming out my exhausted pipe, I believe I have a crack head on a 2002 dodge ram 1500 , will the blue devils seal the problem

      • BlueDevil Pro on June 30, 2016 at 8:27 am

        Lewis-

        Thank you for asking about your Dodge Ram 1500. Based on your description, we would recommend using the BlueDevil Head Gasket Sealer, found here on our website: http://store.gobdp.com/head-gasket-sealer-38386/ . As long as you are not losing water/coolant too quickly and the vehicle can maintain idle for 50 minutes, you would be a good candidate for the product. Feel free to contact our technical support line at 888-863-0426 with any other questions.

        Thank you!

        -BDP

      • BlueDevil Pro on June 30, 2016 at 9:16 am

        Lewis-

        Yes, we recommend using BlueDevil Head Gasket Sealer (http://store.gobdp.com/head-gasket-sealer-38386/) to stop the leak. The product has worked extremely well in sealing head gasket leaks where you see steam or water coming through the exhaust.

        Thank you!

        -BDP

  20. Duce on September 17, 2015 at 11:19 pm

    I have a 99 Honda passport and steam coming out my tail pipe I believe I have a blown head gasket, will your product fix it?

    • BlueDevil Pro on September 18, 2015 at 10:18 am

      Duce-

      Please contact us at 888-863-0426 so that we may discuss the symptoms in a little more detail. We would like to have a better idea as to what the Honda is experiencing so that we are able to make the best recommendation.

      Thank you!

      -BDP

  21. Hores on September 22, 2015 at 12:40 am

    how to get this item???

    • BlueDevil Pro on September 22, 2015 at 8:49 am

      Hores-

      You can find our products on our website, gobdp.com/products . You can also find them at your local Advance Auto Parts, AutoZone, O’reilly Auto Parts or Napa Auto Parts.

      Thank you!

      -BDP

  22. Matt on September 23, 2015 at 11:37 am

    I had either a blown head gasket or a crack somewhere in the engine. Was smelling gasoline in the coolant and getting small amounts of water in the oil. I used Blue Devil with some degree of apathy and pessimism. My tune changed real quick cause this stuff works. Thank you Blue Devil! Getting parts or engines is impossible in a 3rd world island.

  23. jimmy on October 21, 2015 at 9:02 am

    my 2009 Camry motor had small crack they said fixed with
    Blue Devil, now they’ve recalled my car for the oil enhancement
    problem replaced all pistons,rings and rods will this put
    to much stress on engine to make it undo Blue Devil’s weld

    • BlueDevil Pro on October 21, 2015 at 11:18 am

      Jimmy-

      Thank you for your question. Once the product seals, it would be a permanent seal. Replacing the pistons, rings and rods would not effect the weld the product created.

      Thank you!

      -BDP

  24. jesse on October 22, 2015 at 11:28 pm

    Hello I have a case 580c backhoe with a 207 motor with a crack between 2 cylinders it is diesel would this product work already pulled head don’t want to reassemble if it would work?

    • BlueDevil Pro on October 31, 2015 at 11:37 am

      Jesse,

      Thanks for your question about your Case backhoe. As long as the location with the crack is in a coolant passage BlueDevil Radiator and Block Sealer is guaranteed to seal your leak and get your backhoe running again. If the 2 cylinders do not have a water jacket between them then unfortunately you will need to have your block welded and machined.

      Thanks again for your question!
      -BD Auto Pro

  25. king on October 25, 2015 at 2:26 am

    my car is a Mercedes benz A170, 1999 model. i just recently found out that when i put oil in the car, the oil goes straight to the radiator of the car when i put on the engine and and pump out of the radiator when i open the radiator. can your product do rapair it

    • BlueDevil Pro on October 27, 2015 at 3:51 pm

      King-

      Unfortunately, we do not manufacture a product for the leak you have described. The BlueDevil Head Gasket Sealer is only intended for coolant leaks and the BlueDevil Oil Stop Leaks would only be for the rubber seals or rubber gaskets in the system.

      Thank you!

      -BDP

  26. Jesse duncan on October 28, 2015 at 5:03 pm

    Can blue devil clog a crack in cylinder in block of 03 landrover discovery

    • BlueDevil Pro on October 30, 2015 at 9:07 am

      Jesse-

      Yes, BlueDevil would be able to seal the leak in the block of your Landrover Discovery. The product is intended for leaks that are seeping or dripping out, so as long as you are not losing water/coolant too quickly, the product should be able to seal your leak.

      Thank you!

      -BDP

  27. Rob Warbington on October 29, 2015 at 8:33 pm

    Will it work on a 2000 dodge carvan if the block is cracked

    • BlueDevil Pro on October 30, 2015 at 9:05 am

      Rob-

      Yes, BlueDevil is able to seal leaks coming from the block. As long as the vehicle can idle for 50 minutes without overheating or stalling out, and you are not losing more than about a quart of water/coolant during that idle period, the product should be able to seal your leak.

      Thank you!

      -BDP

      • Mike B on July 4, 2021 at 10:09 pm

        I have a 09 Suzuki Grand Vitara 2.4, it has a small hairline crack about an inch long, in the aluminum block external above the oil filter, only leaking antifreeze, it never leaks a lot and the vehicle never overheats, I like to use Blue Devil I’ve been kind of hesitant, because I’m afraid is going to clog up my heater coil or thermostat, please help with this??

        • BlueDevil Pro on July 6, 2021 at 8:36 am

          Mike-

          Thank you for asking about your Suzuki Grand Vitara. Based on your description, you would be a good candidate for the BlueDevil Radiator & Block Sealer. The product does not contain any solid or particulate matter, so it is a non-clogging product. Feel free to contact our technical support line at 888-863-0426 with any other questions.

          Thank you!

          -BDP

  28. Rob Warbington on October 29, 2015 at 8:34 pm

    Will it work on any engines

    • BlueDevil Pro on October 30, 2015 at 8:41 am

      Rob-

      Yes, the BlueDevil Radiator and Block Sealer is compatible with all engines.

      Thank you!

      -BDP

  29. jerry fant on November 2, 2015 at 1:43 am

    I have a 350 that has a sleeve on number 3 cyl. The sleeve is leaking around the top of it and the orignail part of the block.i get water in my oil and thrue my exaust pipe. Will this product work on this problem

    • BlueDevil Pro on November 5, 2015 at 10:56 am

      Jerry-

      Yes, BlueDevil would be able to seal the leak you have described. As long as you are not losing water/coolant too quickly and the vehicle is able to maintain idle for 50 minutes, without overheating or stalling out, you should be able to see some great results. We would also recommend changing the oil before and after the BlueDevil process.

      Thank you!

      -BDP

  30. David mach on November 22, 2015 at 5:47 pm

    I have a 94 6.5 turbo diesel with a crack in the 8th cylinder interior how would i use bluedevil and is it gaurented to work?

  31. mehr on November 24, 2015 at 12:34 am

    hi
    i have a Peugeot 405 1800cc fuel(petrol) injection engine
    its block cracked
    is helpful your products for repair it , please tell me about how use and how much use
    thanks a lot

    • BlueDevil Pro on December 1, 2015 at 9:51 am

      Mehr-

      Yes, the BlueDevil Radiator & Block Sealer would be appropriate to use in your Peugeot to seal the cracked block. One 16 ounce bottle will treat up to a 3 gallon system.

      Thank you!

      -BDP

  32. Simon on January 13, 2016 at 11:18 am

    Hi

    Will this product cure a crack in an aluminium block? I have a coolant leak into the oil sump from a leak between an engine sleeve and the block.

    • BlueDevil Pro on January 13, 2016 at 3:08 pm

      Simon-

      Yes, BlueDevil would be able to help seal a leak in an aluminum block. As long as the vehicle will idle for a full 50 minutes, without overheating or stalling out, and you are not losing more than about a quart of water/coolant, then you should be able to see some good results from the product. Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!

      -BDP

  33. Tom on January 19, 2016 at 10:09 pm

    Will it stop up the radiator or header core”

    • BlueDevil Pro on January 20, 2016 at 11:10 am

      Tom-

      The product does not contain any solid or particulate matter, so it will not clog or harm your cooling system. Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!

      -BDP

      • Harry reedy on January 27, 2016 at 9:47 am

        Can you mix with andifrezz

        • BlueDevil Pro on January 27, 2016 at 3:38 pm

          Harry-

          Yes, BlueDevil Radiator & Block Sealer may be mixed and used with antifreeze.

          Thank you!

          -BDP

  34. john on January 20, 2016 at 9:34 pm

    i have a wd 45 diesel 230 buda engine that has 3 crack between different cylinders will you have product that?

    • BlueDevil Pro on January 21, 2016 at 12:02 pm

      John-

      Please contact us at 888-863-0426 so that we can get a better idea of the extent of your leaks. This will allow us to make the proper recommendation for your engine.

      Thank you!

      -BDP

  35. Lance on February 24, 2016 at 10:10 am

    I have a 95 firebird 3.4 v6 and when the temp rises to normal it starts to smoke and I can’t tell if it’s the gasket or the block. If this stuff can help will it block or clog up anything

    • BlueDevil Pro on February 24, 2016 at 10:13 am

      Lance-

      Thank you for asking about your Firebird. There are no solid or particulate matter in the product, so it is non-clogging. As long as you are following the directions and using the product as intended, you wouldn’t have any issues with clogging.

      Thank you!

      -BDP

  36. Bob Maine on February 27, 2016 at 6:02 am

    I have a 98 saturn with 1.9 leaking oil into the coolant reservoir will blue devil work for that?