Head Gasket Won't Seal!


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The following comes from a recent topic on SmokStak at Various individuals started, commented on and concluded the following bulletin board thread.

I have two Waterloo style engines, a Gault and a Majestic. They both make the water in the water hopper bubble on the compression stroke. I have put a new head gasket on the Gault and it still leaks when it is running, but I have not done anything to the Majestic. Neither of them have any cracks in the heads that I can see, but the old head gasket on the Gault showed a bad spot that was causing the leak. Now I cannot get the new gasket to seal completely. How can I get the head gasket to seal, or is there a proper procedure for this? - C.

You might try laying a straightedge across the head to see if you have any low spots. I'm not familiar with that type of head, but I have taken various heads and resurfaced them using a flat piece of glass and stick-on sand paper - if it isn't warped too bad. Just a thought. -Sam

Be sure you are not running out of good, clean threads on your head bolts before you are getting full clamping force on the gasket. Be sure the gasket mating surfaces are not severely pitted or warped. If the head bolt threads in the block open into the water jacket they need to have a sealer on the threads. If the head bolts have not been out recently and do not come out easily, they are probably sealed with rust. If there is heavy rust build-up on the studs at the block, it may be preventing good crush on the gasket. Lubricate the threads and the nut mating surface to the head so you do not get a false torque. - Ed

I always coat head gaskets with gun grease and let it soak in a while. It softens them up a little and keeps them from sticking if you have to remove the head. Never had any leak. - Glenn

I had a couple of head gaskets leak on old stationary engines. Know what I used? High-temp silicone sealer on the gasket. I have been running it for three years now with no problem. And yes, I do run it until the water steams so it is as hot as it can be. I used the blue silicone on one and the orange high temp on the other. Works great. - Steven

I've also used the blue silicone on many engines, including large oil field engines, and it has never failed me yet. I have one engine that it has been in for over 10 years now and still no problems. - Tom

I had a small Jaeger that had sealing problems. It had some pits that were significant. I cleaned the heck out of things and brightened them up with emery cloth and then used a special high temperature epoxy to fill the pits. JB weld and other epoxies don't seem to work too well in a high temperature application, but this stuff is bullet proof. I got it dead flat with a straight edge after application and no problems since. - Bob

I've never used silicone, but I've had great luck with Copper Coat. There are probably a couple different manufacturers of the stuff. It's a spray-on sealant with a high copper content. As others have said, make sure everything's absolutely clean so you're getting full clamping force. I've never had it fail. - Richard

In my early days, when I had just a few dimes, I used soft soap on both sides of the gasket and it never leaked again. Now in my better days, I use a rattle can with aluminum spray that withstands 1800 degrees F, and I haven't had any leaks either. It's worth it to try once. - John

An old timer also said to paint both sides with aluminum or silver paint. It is also supposed to work to seal stains from bleeding through paint. Another thing is to note if the new gasket is too tight to the stud bolts. It can crush and bind at the bolt creating a lump or tight spot. A slight chamfer on the head-bolt holes will relieve that tendency and actually allow the pressure to spread out wider from the bolts. - Lars

I just use 30 weight oil on my gaskets. Rub it in and let it sit for a few hours before you assemble. Don't forget to re-tighten after the first time the engine runs. - Scott

I soak mine in boiled linseed oil overnight - never had a problem yet. I read in an old engine manual somewhere that soaking in water will do the same. - Nick

Thanks to everyone who replied. I soaked the gasket in oil overnight and I put it on today. When I ran it, some small bubbles came up through the water hopper. The more I ran it the less bubbles. After it was hot I tightened the head bolts. Now it doesn't bubble at all. Again, thanks for all the great ideas. - C.

The above discussion can be found on the Internet at SmokStak is an engine conversation bulletin board and is part of the Old Engine series of web sites that started in 1995 as 'Harry's Old Engine.' Harry Matthews is a retired electronic engineer and gas engine collector from Oswego, N.Y., now residing in Sarasota, Fla.