is putting high temp silicone on a new exhaust system a good idea?
i have to use a donut gasket to connect the headers to the cat and was wondering if putting high temp silicone was a good idea…
If you need to use anything use high temp gasket maker not silicone…I doubt silicone would hold up very long.
DO NOT use any liquid gasket or sealant on your donut gasket. The donut gasket is made to seal on it’s own, it doesn’t need any help. In a pinch, for a temporary fix you could seal a leaky donut gasket with some type of high temp sealer (made for exhausts) but it’s not going to last long, and possibly not even work whatsover.
There’s a reason why you use a donut gasket at the joint from the header to the cat, it’s because the header and exhaust systems are designed to move independently of each other. Think of it like a ball and socket joint - like your knee, shoulder, or elbow, or even a heim joint. The engine vibrates and moves as you rev it and shift, if your exhaust was solidly mounted to the header you’d end up breaking things due do the movement.
Gasket sealer will act as glue essentially, freezing that ball and socket joint. But not for long since the sealant isn’t all that durable and the engine movement will surely destroy any bond the sealant tries to make.
Liquid gaskets on exhausts systems are bandaids and should be avoided at all costs. Use the right gaskets and you’ll have better results.
Liquid gaskets on exhausts systems are bandaids and should be avoided at all costs. Use the right gaskets and you’ll have better results.
True that. I have however used it successfully when I absolutely could NOT find a gasket to go between th top and bottom of my 2 piece aftermarket header. I had to make one out of two pieces of thick gasket paper and bonded them together with gasket maker. It was the only thing that did not blow out, but that was on a join that had no movement what-so-ever…Unlike that doughnut gasket the OP is talking about.
I also used it with another homemade throttle body gasket on my mazda.
Again though, both instances were when I couldn’t get the proper gasket so i had to make due. Just wanted to mention that the stuff does work when properly applied and your in a pinch. Both gaskets are still holding up today.