Head gasket - use sealant ?
 

Hi Guys,

I have been advised by a "professional" to use sealant or even normal household paint to seal the new headgasket onto the block and head. The manual doesn't show anything other than to use the new gasket which is actually three layers (two carbon looking with a metal sheet in the middle) so i am not 100% convinced on his advice.

Has anyone replaced the head gasket with or without sealant ?, as always your wisdom is welcomed.

Thanks

I have never replaced the head gasket on a bike, but , being a mechanic by trade, I have replaced plenty on cars trucks, tractors and boats. That being said, I have NEVER used any sealant on a head gasket. They have all installed dry. That is what most are multi layer. To dealwith the different expansion rates of a block versus the head. If it your in doubt, default to the manual. But sealing a head gasket just sounds off to me. I've never done it and never will. Just my .02 cents

I'm also a professional. Metal headgaskets can be put on dry provided both surfaces are resurfaced true. If one or both are being cleaned and reused there is a chance that fluids can leak by way of imperfections of the surface. I use copper coat spray on both surfaces and the gasket to help seal it and help hold it in place while putting the head on. Using tacky paint may do the same in a pinch, but seems kinda ghetto on such a crucial area.

I changed the head gasket on my F2 a couple of years ago. I didn't use any sealant, just put the gasket on dry. I made sure all surfaces were clean and undamaged and torqued the cylinder head bolts to spec. It's never been a problem since.

99% of the time dry is fine. Its that 1 time that it leaks and the entire job needs to be redone that makes a simple spray of sealer worth it. Its too big of job to take the chance for me....

hmmm

Is there any negative to using copper sealant, in my untrained and idiot mind i thought anything between the two surfaces would have hindered a good seal. If it is only going to help my chances i am up for it though.

both surface have been cleaned and checked by an engineering shop so at least i should have a good starting point.

I have seen this used. My apologies to the op. When sealant was mentioned I automatically assumed rtv was the sealant. A Cooper coat spray would be rather thin and therefore only filling imperfections as 74 said. I have no experience with it as I have always replaced them dry and luckily never had an issue. Of course, when replacing head gaskets I usually have the heads sent of to be checked too. As far as what you use, if your not having the head and block checked, then it would seem the spray is cheap insurance against a slight leak.
Thank you 74 for the explanation and suggestion of a safe sealant. Learn something new everyday. And I'm never too smart to learn. Plus, you may have just saved me a major headache

sorry i think that was more my fault, i wasn't very clear with the use of "sealant" I did mean copper spray or similar not that horrible sealant / silicone stuff.

Well, I will be using a spray of copper over the gasket before applying and hopefully getting this thing together !.

unfortunately after being convinced by you guys i can not find copper spray available here in the uk :-( even tried evil bay and amazon.
there are a few copper adhesive type products from a tube but non are recommended for head gaskets.

It's made by permatex. If its not sold there, don't sweat it. Put it together dry, you will probably be just fine.