Can I Drive with a Cracked Engine Block?

engine block, cracked engine blockDriving with a cracked engine block is like driving with any other leak in your car. It will get worse when your engine is hot and will continue to get worse over time.  Leaks are of course messy and usually smelly but are they really dangerous to drive with?

Oil leaks can be dangerous to drive with as they can cause a low oil level.  Oil starvation is a quick killer of any motor. As the oil level gets low in the oil pan the oil pump no longer can provide pressurized oil to the bearings which can quickly ruin them.

Depending on where the crack is in your engine block, it is possible that it is causing an oil leak, but most likely your cracked engine block has shown up as a coolant leak.  Coolant leaks can lead to lots of other problems especially if it is leaking from a cracked engine block.

Problems due to a coolant leak from a Cracked Engine Block

  • Electrical Shorts
  • Depressurized cooling system
  • Blown Head Gasket

Electrical Shorts

Anytime you’ve got a cracked engine block hot high-pressure coolant will escape after your engine heats up.  This hot coolant will spray into the engine bay of your car and get anything and everything soaking wet. Water and electronics have never played well together so this soaking of your engine bay will quickly turn up broken electrical components and electrical shorts which can be very difficult to track down and expensive to fix.

Depressurized Cooling System

Your cooling system is designed to run anywhere from 10 to 18 psi.  The pressurization of your coolant increases the boiling point of the fluid.  The normal operating temperature of most cooling systems is high enough to boil the coolant at atmospheric pressure.  Boil coolant doesn’t cool as well and will leave hot spots in the engine and heads causing warping and other damage that may require a full engine rebuild to repair.

Blown Head Gasket

A low coolant level or depressurized system can quickly lead to overheating.  Anytime your engine overheats, it’s possible to blow a head gasket due to warping heads.  If you’ve already got a cracked engine block you need to repair that part of your engine, but most likely your cylinder heads can be reused.  If you let the cracked block cause more problems you may end up needing to replace your entire motor.

Driving with a cracked engine block will lead to other problems more quickly than you think.  While welding or cold metal stitching are repair options they both are costly and take a lot of skill and do not guarantee a permanent repair.  Luckily, there is another option that doesn’t require removal of your engine and can be installed simply and in most cases without any tools. BlueDevil Radiator and Block Sealer is a sealing agent that mixes with your coolant and will seal your cooling system making it safe to drive with your cracked engine block.







You can find BlueDevil Radiator and Block Sealer at any of our partnering local auto parts stores like:

  • AutoZone
  • Advance Auto Parts
  • Bennett Auto Supply
  • CarQuest Auto Parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Fast Track
  • Bumper to Bumper Auto Parts Specialists
  • S&E Quick Lube Distributor
  • DYK Automotive
  • Fisher Auto Parts stores
  • Auto Plus Auto Parts stores
  • Hovis Auto & Truck Supply stores
  • Salvo Auto Parts
  • Advantage Auto Stores
  • Genuine Auto Parts stores
  • Bond Auto Parts stores
  • Tidewater Fleet Supply
  • Bumper to Bumper Auto Parts
  • Any Part Auto Parts
  • Consumer Auto Parts

Pictures Provided By:
cracked_engine_block.jpg – By Urfinguss – Licensed by Getty Images – Original Link

12 responses to “Can I Drive with a Cracked Engine Block?

  1. I just got my spark plugs changed and when they were removed there was oil on them
    What does this mean and can I still drive my car with proper oil changes

    1. Kristi-

      There are a few different reasons as to why you would see oil on the spark plugs. You could have some seepage around the spark plug well gasket, allowing a little oil on the spark plug. You could also have leaking valve cover gaskets. Try using the BlueDevil Oil Stop Leak ( If the leak is coming from one of those rubber seals/gaskets, you would be a good candidate for the product. The product does not harden or thicken in any way, so it would not cause harm adding the product, even if the loss of oil wasn’t coming from a rubber seal.

      Thank you!


    1. Carol-

      How quickly are you losing water/coolant? Is the vehicle overheating at all? 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!


  2. I purchased a 1990 Acura Integra which had a blown head gasket that has been replaced and he rebuilt the entire top end of the block. For some reason after 20 minutes of him driving the car it is acting like the head gasket is blown again from what he says. There’s a lot of pressure going into my radiator while the car is being started. If you open the radiator cap it just bubbles and forces all the radiator fluid out. Will Blue Devil work on this, and if so how am I to get it to run through the system without it bubbling out of my radiator?

    1. Joshua-

      Thank you for asking about your Acura Integra. Based on your description, it’s 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!


  3. I have a 2005 hydunai Santa ‘ve and had the motor redone a year ago.
    2 weeks ago my stepdad drove it to Birmingham and on his way back he drove it until it quit the radiator was cracked. So I bought a new one.
    The question is why would my 3 spark plugs and plug wire be totally melted?
    And are there a possibility of a cracked head or block?
    What do you suggest would be the best thing I could do?

    1. Teresa-

      Thank you for asking about your Hyundai Sant Fe. A melted electrode on your spark plugs means that they’ve been running the vehicle too hot for too long and could burn a hole through the top of a piston. Have you noticed the vehicle overheating? Does your coolant seem to be showing at the proper level? 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!


  4. I have a 1994 bmw 525i and there’s a little crack on the bottom of my motor which it’s leaks oil on the exhaust Pipe do I have to drain the oil then put some blue devil on it ? And my car is overheating is it because of the crack i already changed the thermostat and the radiator is works and so does the water pump I checked the transmission fluid it was low I haven’t got the chance to put new tranny fluid in it , it’s just sitting there so I’m wondering is it overheating because of the crack or lack on transmission fluid ??

    1. Jair-

      Thank you for asking about your BMW 525i. You mentioned noticing an oil leak, have you also noticed a loss of 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!


  5. i have a 95 Acura Integra RS, i needed a radiator and wind up blowing a head gasket. I did some research and found that Blue Devil was number 1.
    So the next morning i got up a lil reluctant ans used the product. My car is running as if the crack head never happened.
    Thank u Blue Devil

    1. C. Hannibal-

      That is excellent to hear! We’re glad you had successful results using the BlueDevil Head Gasket Sealer. Once the product seals, it would be a permanent seal, so you should be good to go at this point. We appreciate you leaving us your feedback.

      Thank you!


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