Blown Head Gasket

blown head gasketHow do you know if you have a blown head gasket or not? Did your mechanic tell you that your engine over heating problem was due to a blown head gasket or some other internal engine leak? How do you know he is right? Do you spend $2,000 just because he says that is the problem? What tests should you recommend your mechanic do and what questions should you ask?

I made this short video talking about my recommended head sealer. I would love to hear your comments below about this video. Did it help you? Were you bored? Would you like to see more videos like this on this site….instead of having to READ my articles? 🙂 Thanks!

Posted in: Head Gaskets

32 Comments on "Blown Head Gasket"

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  1. John says:

    Two questions regarding issues with a Ford 5.0L 302 V-8. After applying sodium silicate to resolve a blown gasket problem, I have had a mixed bag success. The lifters are now somewhat “sticky” (clacking sound). Can that be resolved? Second Q: Overheating water (little geiser) under throttle body just above valve cover. What broke? Thanks.

    • Austin Davis says:

      I would check oil pressure with a manual gauge, if ok, try adding a can of Mystery Marvel Oil additive to the crankcase and see if that quiets the noise. I would then get a cooling system pressure test to look for external coolant leaks causing overheating, and radiator restriction causing overheating. Head gasket failure was due to overheating and was a symptom, not the cause…find and repair the cause.


    RE: YOUR directions for K&W Block Sealer (blown head gasket). After exhaustive research I have decided to go with your expertise. But I do need some clarification because I want to follow YOUR directions to a T. Questions: Regarding the INITIAL mix of K&W Block Sealer with water, what’s the exact amount water to use? (equal amount, 1 quart, 3 quarts?).What extent will the “milkshake”(coolant/oil)already in engine effect the sealer? Oil change BEFORE sealer application? Thanks.

    • Austin Davis says:

      How ever much water it takes to completely fill the radiator, no set amount. if the oil is milkshake looking, change it now, its not good to continue to drive with water in the engine oil.

  3. Pamela says:

    I am planning to use the K&W Block Sealer (orange can) for a crack in my head gasket. My water pump has a small leak in it but my car is not overheating (the cause of the overheating was the fan relay now working). I was thinking about using the block sealer first following your instructions and driving the 500 miles (about a week or two of driving). Then after that I will drain the radiator, change the water pump, and timing belt. Is this a bad idea? Should I change the water pump before using K&W?

    The main reason I would like to wait on changing the water pump is in case I end up needing to replace the head gasket. I don’t want to have to do all the work again. Thank you for any and all help.

    • Austin Davis says:

      You should replace the pump first, then pressure test the cooling system again to make sure there are no other leaks. I would drive it awhile after the pump has been replaced and see if you still need/want to use the sealer.

  4. Ronna D says:

    Hi. I have an 09 dodge journey. My car keeps sporadically running hot. I had the radiator replaced about 3 years ago and have replaced the thermostat multiple times. Recently after a long trip the cars engin sounds horrible and it doesnt seem to have as much power. I have noticed that the coolant sometimes bubbles back up into the jug. It has a rough idle. I am constantly having to add coolant. And sometimes the heater will not work and it will run hot then. Please help. It is a head gasket or maybe the heater core? I have not seen any moisture in the passenger floorboards. It tends to run hot when idoling or stop and go traffic. When you get going good the temp usually goes back down to the middle line.

    • Austin Davis says:

      You need to get a cooling system pressure test to determine if you have an internal (head gasket) or external (hose, or water pump etc. etc). Kinda sounds like you have a leak and are low on coolant causing the overheating, and overheating can cause loss of engine power/performance. Keep me posted.

  5. Kyle says:

    Mustang GT 4.6.. Was loosing coolant with no sign of exterior leak and refilling radiator cosistantly.. now missing on no. 8 cylinder according to scantool.
    Got the K&W in the metal can.. the block seal.. flush, flush, flush, flush and added the can. Right now I have about 30 miles on the car.. driving easily. The car is in the driveway idling and I will likely let it idle for another 30 to 45 minutes or so. Flushed until clear and a bit more for good measure.
    Could you share different timeframes for it to take effect?

    • Austin Davis says:

      Sounds good so far, right? I usually advise my customers to leave the sealer in for 500 miles before draining out. Give it the best chance possible to take effect, when it does its a permanent seal.

  6. frank says:

    My 2003 IS300 is overheating. At 1st the colling fans were not working so I was running the air condition so the a/c fans would overide the cooling fans and kick on. It worked, but then this morning it overheated and looks like the water is fizzling or boliing out the top part on the back of the engine. Could this be a blown head gasket?

    • By Austin Davis says:

      No probably not. I would get a cooling system pressure test to find the leak. I would assume the coolant you see boiling is where the leak is and your radiator is low on coolant causing the overheating

  7. TJ says:

    Love your site Austin 🙂 And yes, I also gave her the new thermostat and timing belt kit, oil change, new coolant etc. It has well over 230k miles and had no sign of wear in the sylinders. And after getting her back on the road, I’ve put 5k on it, so I’m lucky. First time I’ve done this big a job on a newer type of enginge and I am not a mecanik. Have a nice hot day in Texas. I’m in Norway and have only 60 today.
    Kind regards,

  8. TJ says:

    My Camry with the 5sfe engine had a leak between the exhoust and coolant, causing the coolant to cook at lower temperature than thermostat would open. Modifying termostat so only the ring and gasket remained, to ensure free sirculation showed that the exhoust smoke came out of of the radiator in less than 2 minutes starting from 40 degree temperature. Then I tore the enginge down and changed the HG. Could I have used the sealant in stead? Would have saved me a lot of work in the garage.

    • By Austin Davis says:

      Hi TJ, yes I would have recommended the sealer in this situation…can’t hurt to try it and might have saved you a lot of time and money.

  9. Bethany says:

    Oh and its only 80* degrees right now. 🙁

    • By Austin Davis says:

      Just so you know what the sealer is and what it does.

      That sealer has flakes of copper in it, those flakes will melt when they come in contact with high heat from combustion gases that the cylinder is giving off. When it melts, it will seal the hole where the combustion gases are coming from. It will not clog the radiator, or any other part of the engine or cooling system because those areas are not hot enough to melt the copper flakes.

      When you drain out the sealer mixture you will still see most of the copper flakes I am talking about. Only a small amount of the copper will find the hole and melt to seal it closed.

      Kinda strange analogy, but just like fertilizing an egg. Only a very small amount of sperm find the egg, and only 1 will do the job the rest do nothing. It can take time to find the egg, and sometimes they don’t find or fertilize the egg at all, which is why I recommend leaving the sealer in the engine for 500 miles to give it all chances to find and repair the small hole where ever it is.

      If the copper flakes find the hole, it will seal it…just how long will it take, that is the question and will it ever find the small hole causing the leak.

  10. Bethany says:

    he just broke down on the freeway. We did the block test, one cylinder out, low compression and exuahst so I thought we would try the KW. Since the KW its waaaay worse so maybe not the trick for me. Going to tow him back home…

    • By Austin Davis says:

      Sorry to hear that, wish I could be there to see what is going on. Some things to consider are.

      1. If you actually have low compression on 1 cylinder, the engine will run rough, especially at idle and will not have the power it used to have since you now have a 5 cylinder engine (or 3 cylinder if this is a 4 cylinder engine)
      2. The block sealer should NOT make things worse, especially at 80 degree outside temp. So, my thought is there is something else going on….like a radiator restriction that is not allowing the coolant/water to flow properly in the engine.
      3. If you do have a headgasket type of issue I would expect there to be white smoke out the tailpipe, engine running rough, lack of power, and sometimes a check engine light coming on the dash because 1 cylinder is not working properly.
      4. You can remove the spark plug from the “bad cylinder” and I would expect to see some white powerdery reside on the tip which would be from coolant getting inside the cylinder.
      5. If the engine is damaged or worn out, and low compression on a cylinder the engine has to work twice as hard to make up for the loss of compression…which can cause over heating. You might have a problem with the valves on that cylinder, or some other internal engine damage which will not be corrected with the sealer and will need to replace those damaged/worn parts.
      6. Since you tell me the problem is worse…it just leads me to think the radiator can not remove the heat the engine is producing, and its producing more heat with no coolant to help it remove the heat.
      7. Turning on the heater will help remove that heat because there is a small radiator inside your dash, this can help him limp home. If the heater is not hot, then there is no coolant in the engine, or a restriction that is not allowing the coolant to get to the heater core in the dash.

  11. Bethany says:

    Hi Austin,
    So this weekend I completly drained and flushed the radiator. I then added the block sealer with water per your instructions. My son drove the truck to work and it overheated by the time he got there. The resevoir was empty so he added some water to it. It then overheated again on the way home. The resevoir filled up and was still extremly hot 3 hours later as so was the radiator cap. It did not overheat that hot before me adding the sealer and he had driven it in 111* degree heat. (We live in Arizona)Today was cooler at 108*. I am confused. Should I have just left things alone??

    • By Austin Davis says:

      With the sealer added you will not have boil over or freeze protection since you are just using plain tap water to help cool the engine. 111 degrees is pretty hot! If the sealer is going to work for you, it should seal any internal leaks pretty quickly, say 30 minutes or so of normal driving. The 500 miles part was just a way to make sure the sealer found and sealed all possible leaks.

      I would not really expect to see overheating or boil over on normal 60MPH freeway driving when there is plenty of air coming through the radiator….unless there is a restriction in the radiator preventing it. Stop and go traffic could produce overheating with 111 degree outside temp. See if you can get 50 miles of non stop freeway driving in, then if you want you can drain and refill with the proper coolant/water mix (50/50)

      If you are loosing water and having to add, then that water is going somewhere and if you had an internal engine leak it should be coming out the tailpipe as steam. If its just boiling over in the plastic bottle…I would suspect a radiator restriction first or its just way to hot outside to use just plain water. I answer so many questions each day I forget…you did not replace the radiator correct? This still sounds like a radiator restriction more than anything else, and the radiator just is not doing its job.

  12. Bethany says:

    So I am confused… use the block sealer or do the repair? I am thinking it cant hurt to try…

    • By Austin Davis says:

      Sorry, try the block sealer first and drive 500 miles as per my directions and keep us posted as to the outcome.

  13. Bethany says:

    Hi Austin,
    We’ve spoken a couple of times regarding my sons Ford Ranger. It was overheating during stop and go or idle or when you parked it after about 30-40 minutes of driving. I did get a block test done and found that the one of the cylinders are bad, he has very low compression and gas exhaust. I have someone who can fix it for under 1000.00. What do you think? KW? or just fix it. I have heard that its great (KW) if youre wanting to sell the vehicle but otherwise it just make a mess in the system.

    • By Austin Davis says:


      Sorry to hear about the low compression issue. Now if this is a problem due to a tear in the headgasket, then YES use the block sealer additive as per my instructions on this page (not on the can) and see what happens. If the sealer works, its a permanent repair and I have not experienced any negative symptoms using it on my customer vehicles. If it does not work, just drain it out of the radiator and flush out as much as you can, it wont harm anything but it will not work if there is coolant in the system.

      Removing the cylinder head and performing a valve job is probably what the appropriate repair is going to take, and yes $1000+ is what it will take.

      Fingers crossed for you

  14. Janell says:

    Hey Austin,

    Just want to say – I loved your video!
    Instructive in a fun way. Laughed all the way through (but I’ve been told I have a wierd sense of humor).
    Yes, and true, whatever is wrong with my car IS my husband’s fault 🙂

  15. Brenda says:

    Hi its me again. Ok, so i went out after I read your reply & now my car is cranking. Although it has an elec. fuel pump Im having to give it gas. Its idling rough and there is now smoke coming from tail pipe that looks to be mostly white and it feels kinda wet like steam. There is still no water in the oil. I havent driven it yet just cranked it to start flushing the system. I have gotten replacement radiator cap & thermastat already. The EGR sensor looks like it may be bad from where the wires connect – would this have anything to do with the problems? And I havent pulled any plugs yet – plan to replace them and the wires with an oil change along with the other things a few days after I use the sealer – is this the correct way?

    • Austin says:

      Sorry for my delay, was out of town. So you got another mechanic to check this out for you as I suggested? Yes, you should correct the bad wire connection, although not sure that is the problem, and would not cause a cooling system or overheating issue but might make the engine run bad. I would have a more qualified mechanic check this from scratch, pressure test, check coolant flow and possible radiator restriction etc. etc. before I just jumped to conclusion about an internal coolant leak.

  16. Brenda says:

    I have a 1999 Camaro with a 3800 V6 engine. A friend did a cooling system pressure test and he says that the head gasket is blown and that when the car was shut off the loud pop sound I heard confirms this (plus the fact that now the car wont start because the test caused water to go to the plug although it would crank before the test).He showed me on the gauge that it was keeping a steady pressure. There is no water in the oil but there was a small amount of white smoke coming from the tailpie on start up but would stop after a few minutes driving. I know it overheated & Im pretty sure it did this because tof the fan, fan relay, or both. Is he right about the head gasket?

    • Austin says:

      I think I am as confused as your mechanic friend is. I would get a second opinion, this does not sound right at all. If there is a cooling system leak, like from a headgasket, the pressure on the gauge would NOT be steady….it would force the coolant to leak out of the system and the gauge would be going down. You drove the car into the shop for testing but now the engine will not start?? He COULD have pumped the system with too much air and caused a problem. Just like inflating a tire, there is a max pressure you can place on the radiator and the rest of the system. Too much pressure from the pressure test can blow out something….radiator, headgasket (although kinda hard to do) etc. etc.

      I would probably first remove the spark plugs and look for signs of coolant on the plugs or inside the cylinder. If there IS, then yes, you probably do have a headgasket issue and should try the sealer I mentioned and my instructions on how to use it.

      if the plugs are dry, then you have another issue which needs to be investigated. Radiator restriction, electric cooling fan bad, thermostat problem etc.

      I would not be too concerned with some steam/white smoke that comes from the tailpipe on initial start up then goes away.

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