Because both the manifold & the head were still relatively true & UN-rusted, I used the same sealant as the factory - chassis grease in a thin film around each port. When the manifold gets hot, the grease will bake into a varnish, much like cast iron cookware. The varnish creates an effective seal. And like seasoned cast-iron cookware, it's also a non-stick coating, which allows the manifold to expand & contract without cracking. Gaskets can adhere and cause binding; or their steel laminations rust away because their paper or fiber layers trap water; all of which makes cracking, warping, & leaking more likely. The loss of material also loosens the bolts, which vibrate out.

If the surface is too rough for grease to work, use high-temperature silicone.



The white pointer indicates a thermal disk glued to the bore plug by Jasper. If the engine is overheated, the disk will show it, voiding any warranty. This one is out of warranty, but the disk can still perform its function.

Owner caption November 2009 · Photo 66 of 434