Originally Posted by The Critic
Originally Posted by rooflessVW
Originally Posted by das_peikko
Use the Ultra Black instead. Butter both mating surfaces. Wipe off the squeeze-out. Give it a full 24 hour cure.
Good way to clog water passages.
RTV should only be used when specifically called for by the repair procedure, and it should be used sparingly.
Hacks glob it on and call it "good enough."
Agreed. Only use RTV if that was the factory specified sealer for the component. If it came with a gasket, use a gasket. Cleaning up RTV is a major pain and always risks damage to the surface finish.
Also, when you do have to use RTV, never ever "butter" it on. Apply a bead of the correct diameter and allow the two surfaces to squeeze the bead flat. This way you will ensure an even coat.
Originally Posted by kschachn
You have an actual flat gasket that is solely for the thermostat housing? None of my cars do, all of them have a round rubber gasket that fits onto the thermostat and seals both the housing and the thermostat against the head. In that type of application you wouldn't ever use RTV.
Same here - I have only seen o-rings use in this application. Then again, I rarely work on domestic cars so I dunno.
My 4.9L E-150 uses a flat gasket for the thermostat housing. I use a gasket and Permatex High Tack. I never had one leak, I changed quite a few thermostats on them. I've owned and still own 4.9L powered Fords since 1984. I wouldn't think of RTV for that application.