Is Your Head Gasket Blown?


When it comes to your automobile, a blown head gasket is just about the most expensive diagnosis there is, short of what happens if you continue to drive with your head gasket blown. The result of that could be catastrophic engine failure and a trip to the junk yard for a new engine — or to a car dealership for a new vehicle.

What is particularly distressing about how expensive a head gasket is to replace and the absolute necessity that it be done, is how simple and inexpensive the part actually is. Head gaskets are merely thin slices of metal, perhaps a composite, with a variety of holes in them. They don’t move, produce a spark, transfer a fluid, create electricity or really do anything. They’re just there.

What Is a Head Gasket?

The head gasket in a car is just a metal divider, a fraction of an inch thick, that stands between the moving parts of the engine that require oil lubrication and relatively cool conditions, and the combustion chamber of the engine that requires fuel, air and fire to create an explosion. Oil in the combustion chamber fouls up the works and prevents it from functioning efficiently. Heat from the combustion chamber can burn up the moving parts. Coolant leaking into the motor oil reduces lubrication and gums up the mechanical elements that make the wheels turn. And much, much more.

In other words, that simple head gasket stands between a smooth-running engine and disaster. When a head gasket leak develops, oil can seep into the coolant and vice versa. The heat and pressure of the combustion chamber can cause warping in the cylinders. Oil can drip through the gasket into the combustion chamber and prevent combustion or cause the engine to misfire. Oil in the coolant can reduce its cooling capacity and damage a host of parts like the catalytic converter.

If the mechanic diagnoses a blown head gasket, it needs to be fixed immediately. Failing to do so will lead to total engine failure, and soon.

What Is the Cost to Replace a Blown Head Gasket?

You can drive with a blown head gasket until the engine is destroyed. An engine overhaul is a major undertaking and costs $3,000 to $5,000, mostly in the many hours of labor required. Rebuilding a truck engine can cost much more than that.

By that measure, replacing the fifty-dollar head gasket is cheap – an average of $1,500 to $2,000. But when it’s coming out of your wallet, it feels like a fortune.

Why does a blown head gasket replacement cost thousands of dollars when the part itself is under a hundred bucks? Because there is so much labor involved. The head gasket sits between the engine block and the cylinder head, all the way in the back. Almost everything under the hood must be taken apart, moved or removed to access the head gasket.

That is no simple matter. The battery must be disconnected, and the oil and coolant drained. Wires and hoses that are repositioned or removed must be labeled so they can be reattached. Many components such as the valve cover, cylinder head, and intake and exhaust manifolds require their fasteners be removed in a certain sequence to avoid warping or cracking.

After the head gasket is replaced, the timing belt or chain must be reset to its proper alignment and everything else must be returned to its previous position. If all that sounds daunting, it is just a preview of the complexity of the work. Head gasket replacement is a job that can easily take 10-20 hours.

As long as you are paying a mechanic to take everything apart, it makes sense to have them do an inspection of all the parts. If anything is close to needing replacement, this is the time to do it. That will save you money in the long run, but it can push the head gasket bill higher.

How Do You Know Your Head Gasket is Blown?

Many of the symptoms of a blown head gasket are signs of other problems as well. Conversely, many seemingly simple issues are the first signs of a blown head gasket. It is important to pay special attention to these signals because early diagnosis might be able to save you thousands of dollars.

1. The radiator constantly requires additional fluid. This is a common issue that normally does not indicate anything as disastrous as a damaged head gasket. It could be a small leak in a cooling system hose or in the radiator itself. If you find yourself topping off the radiator repeatedly, get it checked for leaks. It’s likely one will be identified and the problem solved. If no leak is identified, a mechanic should search for other symptoms of a blown head gasket.

2. The temperature gauge shows the car running hotter than usual. Again, this may or may not be related to a head gasket leak. Certain normal conditions can heat up the engine. Towing a heavy load, running the air conditioning full-blast, and stop-and-go driving on a blazing hot day can all drive up the temperature. So can loss of coolant, which can happen for a variety of reasons. A mechanic can search for more likely causes before concluding it is a blown head gasket.

3. Bubbles are forming in the radiator and coolant reservoir. This might be nothing. It might be a blown head gasket. Bubbles can form when air gets into the cooling system. This can result from a poorly fitting radiator cap or even from nothing at all. If it persists even after fixing the cap, it is time to suspect trouble.

4. Thick white smoke is coming out of the exhaust pipe. It is important to distinguish white smoke from steam. Condensation can occur when a vehicle is started after standing still on a cold day. In that case, a thin stream of clear or white smoke can emanate from the tailpipe. It is not a problem and should disappear after a minute or so.

Thick white smoke, especially if it is emitted in bursts, is a sign that coolant is leaking into the engine’s combustion chamber. This is never a good thing and should be investigated. Even if it is not a blown head gasket, a crack in the cylinder head or engine block is also big trouble.

5. The dashboard temperature gauge has pinned. Stop the car! Make sure there is coolant in the radiator. If not, address the coolant problem and buy time to determine if there is an underlying issue.

6. The oil is discolored. If coolant crosses the head gasket and leaks into the engine oil, it can give the oil a frothy look, like someone has just whipped up some warm milk. Milk is good for you, but frothy engine oil is not.

7. The engine misfires when starting up. Again, this could have a host of causes, most of them not quite as potentially catastrophic as a blown head gasket. When combined with white exhaust, that is a tell-tale sign that coolant is leaking into the combustion chamber. Get that checked immediately.

If Repairing the Head Gasket Isn’t an Option

If the head gasket is indeed blown or damaged and doing a hard part repair isn’t an option, using a head gasket sealant is a good solution. BlueDevil Pour N Go Head Gasket Sealer is poured into the radiator and circulated through the engine to find and seal leaks in metals and composites. It then bonds to a variety of surfaces for a permanent seal.

While nothing is better than the original parts or replacement parts made specifically for a vehicle, sealant is a great backup plan that can provide a permanent solution while averting large car repair bills.

BlueDevil Products can be found at AutoZone, Advance Auto Parts, O’Reilly Auto Parts, NAPA, Parts Authority, Auto Value, Bumper to Bumper and other major auto parts retailers.

BlueDevil Products can be found on or at AutoZone, Advance Auto Parts, O’Reilly Auto Parts, NAPA, and other major auto parts retailers.

30 responses to "Is Your Head Gasket Blown?"


  1. Abraham Ramírez on November 20, 2021 at 2:00 pm

    I’ve used blue devil head gasket repair more than once and it has done the job every time. When at the parts store I’m standing in front of your formula and the competition I do not think twice in sticking to what I know really works

  2. Joseph Caldwell on December 12, 2021 at 10:42 am

    Happy to hear that ..i have a 2010 duramax that i kerp having to sdd coolant to..its actualky leaking some on the ground wbich i think mostly out ovefflow and not vrry much ..i keep watchi g for pudfles and dont see any very often but sometimes ..and not the amount i have to put back in ..i can dtivd for an hr and a half and it need almost a gallon to top uo .no oil in antifreeze .no antifreezez i.n The oil .. And no major white smoke or smell out the exhaust i list a bunvh of coant after a longer trio onto the ground as i got home ..thought it was water pump but it looks more like the clip on conection for lower rad hose ..that time it jept in draining fr a while and i thought water pump seems fine and im gonna fix the rad hosr but i still think it might b head gasket ..if im lising that much wilk this product wrk ? Has 2_thermous stats which i thought was y it waz pushing coolant ojt but been told probsbly not? Even though i. Having heat issues as well? Im nit a mechanic but i retend when i have too ..Advice?

    • BlueDevil Pro on December 13, 2021 at 8:33 am


      Thank you for asking about your Chevy Duramax. The BlueDevil Head Gasket Sealer is intended for leaks that are seeping or lightly dripping. Based on your description, it sounds as though you may be losing coolant a little too quickly for the product to be beneficial. A hard part repair may be your best option.

      Thank you!


  3. John on May 2, 2022 at 2:16 pm

    I put a bottle of Blue Devil Head Gasket Sealer in my 2010 3.8 Town & Country van. Can I treat it again with a smaller amount to make sure that there is enough circulating in the system to keep working in the future?

    Also, can I run the vehicle without the thermostat for a few days to aid in sealing the head gasket?

    • BlueDevil Pro on May 2, 2022 at 3:31 pm


      Thank you for asking about your Chrysler Town & Country. The BlueDevil Head Gasket Sealer should not be used as a preventative measure/maintenance. The product is only intended for water/coolant leaks. If the vehicle is no longer losing water/coolant, it would not be appropriate to reuse the BlueDevil.

      You are able to run the vehicle without the thermostat, however, it will not help with continued sealing ability. Please contact our technical support line at 888-863-0426 with any other questions.

      Thank you!


      • John on May 4, 2022 at 7:31 pm

        Thanks for the reply. FYI, I couldn’t get the thermostat neck to seal without the thermostat being installed do I had to knock the guts out of the old one and then reinstall the rim piece.

        I’m taking her for a shakedown run of about 80 miles round-trip tomorrow, 70 miles of it are Interstate driving. If all goes well, I’ll pop in a new thermostat when I return. Then I’m put out feelers for a set of heads for the anticipated gasket replacement.

        • BlueDevil Pro on May 5, 2022 at 8:24 am


          The best way to get around the thermostat housing is by taking the thermostat and modifying it so that the middle piece does not close; you may remove this piece or gut the middle of the thermostat. By doing so you will create a free flow and still be able to have the full housing installed. The thermostat should remain “open” while BlueDevil circulates through the system. Once the BlueDevil procedure is complete you will need to replace the thermostat.

          Thank you!


  4. Mike on June 6, 2022 at 3:23 pm

    Hi i have a 2000 exposition and just bought blue devil and haven’t used it but I don’t have white smoke but my oil looks like muddy chocolate milk and i just don’t want to waste the product if it’s not recommended for this so what do u think?

    • BlueDevil Pro on June 7, 2022 at 9:16 am


      Water/coolant mixing in with the engine oil would be a tell-tale sign of a blown head gasket and exactly the kind of leak the BlueDevil Head Gasket Sealer would be intended for. You would want to change the oil before and after the procedure.

      Thank you!


  5. Hope Tozer on June 19, 2022 at 9:04 pm

    I have a 2004 chevy monte Carlo SS not supercharged my oil is fine & my car never over headed but my husband thinks it’s a blown head gasket cuz 3 of my spark plugs had water on them, will the Blue Devil Blown Head Gasket Sealer work?

    • BlueDevil Pro on June 20, 2022 at 10:11 am


      Thank you for asking about your Chevy Monte Carlo. Have you noticed any other symptoms? Is there any white smoke/steam coming from the exhaust pipe? 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!


  6. Willie Austin on August 9, 2022 at 11:49 pm

    Well, absolutely great post here.Very helpful and straightforward.

    My Civic blown head gasket had other signs such as overheating and low coolant level, and P0217 popped up (thankful that it didn’t have other problems).

    I used Blue Devil Head Gasket Sealer, and it worked well.

    But, I have a question: how long does this gasket sealer last (as I don’t use it a lot)?


    • BlueDevil Pro on August 10, 2022 at 7:58 am


      Thank you for your feedback! Once the product seals, it would be a permanent seal. We have customers that contact us 4,5 years down the road, who have done nothing additional to the vehicle, and are still driving around with no leaks. You should be good to go at this point.

      Thank you!


      • Willie Austin on August 11, 2022 at 12:03 am

        Thanks for your reply.

  7. Alok on September 28, 2022 at 9:04 am

    I have a 2015 Kia Sedona SXL that seems to have a failed head gasket. I get bubbles in the coolant a little bit after starting the car. If I rev it up there are more bubbles and the coolant blows out of the reservoir. No white smoke, no milkiness in the oil. I added the pour and go sealer and idled the car for 50 minutes. It did not get any better. When I let it sit for a while, it seemed longer before the bubbles started. It is difficult to get to the spark plugs. Do you think it is a good idea to disconnect one spark plug at a time and run the procedure for 50 minutes as described to see it would help?

    • BlueDevil Pro on September 28, 2022 at 10:05 am


      Thank you for asking about your Kia Sedona. Have you done a block-dye test to confirm whether combustion/exhaust gases are getting into the cooling system? 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!


      • Alok on October 24, 2022 at 12:15 pm

        I am unable to do the block-dye test because the coolant gets pulled into the dye after starting the car and before the two minutes of aspiration that the test requires can be completed. I am seeing seeing white smoke in the morning now. There are bubbles right away when I start the car, even when the engine is cold.

        • BlueDevil Pro on October 24, 2022 at 4:20 pm


          We would be happy to assist you. Please contact our technical support line at 888-863-0426 with any questions.

          Thank you!


      • Dawn on December 28, 2023 at 1:56 pm

        Hello, I have a 1995 jeep Cherokee straightsix 4.0 and it keeps overheating. First there was a leak and a hose I fixed that and then the radiator put a brand new one in there brand new water pump brand new thermostat and housing and it’s still smoking and running hot but not the tailpipe it’s smoking from under the hood on the passenger side could I have a blown head gasket? It’s also running really rough.

        • BlueDevil Pro on January 2, 2024 at 9:34 am


          You can try testing the cooling system to see if combustion/exhaust gases are pumping into the radiator by doing a block-dye test. If the dye changes yellow/green, it’s confirming a head gasket problem or warped/cracked heads. This would explain the overheating issue and also explain why water/coolant is getting into the spark plug(s).

          Thank you!


  8. Duncan Monroe on October 24, 2022 at 3:00 am

    I drive a 2001 Toyota Camry and when my car sits idle the temp stays at that half way mark ( where it’s supposed to be) but as soon as I press the guess and get it goin the temp starts to rise. But when I pull off and just idle it goes back down. Could this be a head gasket problem? If so would blue devil help with this problem?

    • BlueDevil Pro on October 24, 2022 at 9:26 am


      Thank you for asking about your Toyota Camry. The issue you’ve described would not necessarily be attributed to a head gasket leak. Have you noticed any smoke/steam coming out of the tail pipe? Have you had to add any water/coolant? 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!


  9. Michael Thomas on November 21, 2022 at 10:12 pm

    My 94 Ford probe GT leaks water as soon as I put it in so my question is will the Blue devil work on that? I’m sure it’s a head gasket.

    • BlueDevil Pro on November 22, 2022 at 11:36 am


      Thank you for asking about your Ford. Unfortunately, if you’re losing water just as quickly as you add it, you would lose the BlueDevil Head Gasket Sealer just as quickly, and wouldn’t really be able to keep it in the system long enough in order to get the benefit of using it. Replacing the head gasket may be your best option.

      Thank you!


  10. Darren on December 1, 2022 at 5:15 pm

    2014 Ford Escape 1.6l Ecoboost. Coolant has been found in # 3 cylinder and shop suggests small crack in block. Oil still looks normal. Still starts and runs. Evidently a common problem. Radiator/ head gasket or block product best to use? Also, that car type has no radiator cap and not sure which is top radiator hose to pour in product. Why can’t product be placed in coolant resevoir?

    • BlueDevil Pro on December 2, 2022 at 8:59 am


      Based on your description, the BlueDevil Head Gasket Sealer (32 oz. yellow label) would be the best product to use for your Ford Escape. If your vehicle only has a reservoir/overflow rather than a radiator cap, instead of pouring BlueDevil through the reservoir/overflow, with the car off and engine cold you should disconnect the top radiator hose and add the product there; do not pour it into the reservoir. It may be added into the hose or the opening on the radiator. Once BlueDevil has been added, reconnect the hose and start the idle from that point.

      Thank you!


      • Dolly Stanley on December 2, 2022 at 7:15 pm

        My son’s girlfriend has a 04 Chevrolet Trailblazer. The temp gauge goes up and down in it when she’s driving it. We took it to a mechanic and he replaced the thermostat. It did great for two days and then the temp gauge started going up and down again and the heater started blowing cold air. We took it back to the mechanic and he said there were some bubbles in the radiator. He added a half gallon of antifreeze and said it might be a head gasket issue. We don’t know what to do. Any advice on if the sealer would fix this issue?

        • BlueDevil Pro on December 5, 2022 at 8:37 am


          Based on your description, it’s possible the vehicle is 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!


  11. paul on March 6, 2023 at 10:15 am

    My coolant has radiator sealant already in the system. Can Blue Devil be added to this or does the system need to be flushed?

    • BlueDevil Pro on March 7, 2023 at 9:24 am


      You would want to make sure the system is flushed prior to adding the BlueDevil. Mixing two different additives in the system at the same time could cause adverse effects, which you would definitely want to avoid.

      Thank you!


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