infinityron
Contributing Member
I'm replacing the tstat on my older vintage RAW WATER cooled 454. Not overheating but more preventative than anything. The temp gauge not going high but fluctuating a bit which is unusual. My engines pretty much run at 145 all day long. I ordered and await a factory replacement tstat housing kit complete with the housings and internals. My question is.....new one is coming with a spring and a "relief valve"? in addition to the 142 tstat. When I took the old one apart, there was no spring or other valve. What is the purpose of this other valve and spring I am supposedly receiving? Do I need it? Engine was not overheating without it, so I'm just curious. Can't find anything online about older crusader marine cooling guts. Boat is a 1976. I think the blocks are about 1990's but for all I know they could be original. And yes.....they are raw water cooled in salt water and running great.