By September 26, 20114 Comments Read More →

How To Use K&W Engine Block Sealer

Reader Question

Hi Austin. I read a couple of your posts on this subject. I have used K&W
without your “leave it in for 500 miles” trick. I plan to repeat and leave
it in, but 2 things are puzzling me.

1. Does the thermostat really need to be removed? and if so do you leave it
out for the 500 miles?

2. Does the antifreeze need to be completely removed (ie. repeated
flushings)? or will the product tolerate very low concentrations?

Thanks for your help…Bert


Hey there Bert

I do not suggest taking thermostat out, I think another visitor posted a comment about how he did it that way. The product will NOT work properly with any antifreeze in system, although I usually just remove lower radiator hose and flush out radiator as best I can and maybe flush out heater core depending if there really was a good mix of coolant to water to begin with.

You can check out my original post with my instructions here
Austin Davis

Posted in: Head Gaskets

4 Comments on "How To Use K&W Engine Block Sealer"

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  1. D.Martinez says:

    Hi Austin, I did get the pressure test when this happened, and it failed. Was caused by the serpentine belt snapping. They (Pep Boys) believe it may be the head gasket blown, but without further testing the findings are not conclusive. Yes, I probably should get further tests, but they are talking about a couple of hundred dollars additional. And they say if it is the head gasket, for the type of car I have and the miles being 102k, I should just put in a new engine.

    I don’t think this was leaking until maybe the last couple of weeks, or maybe it was leaking previously, but if so it was more subtle. There is no white spoke from exhaust, and I do not see any liquid/water in the oil reservoir – some may be there, but I really didn’t see any with the flashlight. The leak seems to be coming from the head gasket area and when the gas pedal is depressed, more fluid (bubbly white) leaks out of that area, which then hits the belts and inherently sprays onto the hood. I just hate putting more money into this car which I do not plan on keeping long term anyway.

    As it is colder now, my friends say just to drive it to work and back, just fill up the radiator each time before driven – about 9 miles each way. Or can I even put some kind of sealant where I see the leak coming from and hope for the best? So if I can do anything to keep it going until March or April I would be happy. Thanks again for your help.

  2. D. Martinez says:

    Hi Austin, I have a question, but I’ll give you the background first. Have a 2001 Hyundai Accent, 102 K. I tried the head gasket fix like you recommended. I did perform a radiator flush and added the K&W then water. The next day I drove it about 20 miles total. That evening I remembered I had forgotten to empty the overflow tank for the radiator, so to be honest I am not certain if any of that cooland may have went back into the radiator.

    So when I did empty the overflow tank, I noticed it was considerably fuller than it usually is, so some of the fluid I added did go into it, just not sure if it went back to radiator also. Okay, left the original mixture in and took a gamble. Then about 600 miles later, my car did end up getting very warm, so I parked it and got it the next day. I checked the radiator and it was completely dry, but the overflow tank did have water (only) in it still–the stuff I refilled it with when I replaced it. Well, as I drove home the temp remained fine but I have a medium size leak coming from the area of where the head gasket would be.

    My question is should I try the fix again, or is it a lost cause?
    Next question, can I repair the leak with a sealent of some kind to keep my going until spring (does not freeze here in Vegas).
    Final question, if I am driving it to and from work only about 9 miles each way, can I just keep it going as is and just fill up the radiator before leaving home and then again before returning home, or am I going to completely wreck the engine?
    Sorry for all the questions.
    Thanks again!!!

    • Austin says:

      Hey there, Did you get a cooling system pressure test FIRST??? I am NOT convinced you have a headgasket problem, you did not mention white smoke out tailpipe, running bad, water in engine oil etc. etc. sounds like you just have a regular external coolant leak somewhere in the system and you need to locate and repair it. You said this, “medium size leak coming from the area of where the head gasket would be” so you can SEE the leak with your eyes? There are tons of things that can leak and run coolant down the engine and make it look like its coming from one place but it really came from another and ran down the engine and dripped.

      Get a pressure test of the cooling system and hit me back with the findings and we can go from there. Also, make sure they check the electric cooling can motor up at the radiator to make sure it comes on and off properly.

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