trying to figure out which thermostat to purchase for my 1950 Cadillac. my shop manual says the thermostat should stat opening at around 155°-168° and be fully open at 185° yet all the 180° thermostats say they start opening at that temp so I'm just a little confused as to which I should be buying, any suggestions? thanks, Joshua
Old school was running cool. I don’t know Caddy engines, but I’d start with a 180 and make sure things are fine. Warmer engine is less wear, burns off deposits in oil, etc.
Don’t take what I say as gospel. But I can say a 160 is not the best choice. I got worried with the first OT SBC car I bought and the idling temps it would run at. Then found out it was fine
160 has the benefit of (if your cooling system is working well) keeping the underhood temperature 20 degrees cooler than a 180 thermostat. This slightly increases wear in the engine, but can dramatically affect heat soak problems with the carburetor, due to the tendency of modern fuel to boil at a lower temperature than 1950s fuel did.
thats intresting, good to know. My engine had a 180° thermostat in when I took it out so I think I may go that rout again and see the long term results.
your motor will perform way better keeping the heat in the engine and letting the rad have a chance to cool the heated motor coolent... they say... and all my new cars agree,.. best motor temp is a constant 200-210...there I said it.... flame on
The shop manual is out of date because of changes to the formulation of antifreeze. What we have to remember here is that when these cars were new, alcohol-based antifreeze was mainly used. Alcohol boils at a lower temperature than the Ethylene-Glycol-based stuff we use those days, and that was a major factor in running lower rated thermostats. You could lose your antifreeze on a hot day if you were not careful. Thermostat choice used to be a compromise between engine wear and losing your coolant. These days, with better coolant, we can concentrate on "boiling" the contaminants out of your oil without worry. I always run 180 degree thermostats, and have been tempted to try 195's someday in my '51, since I am up here in north-central Minnesota, where it stays pretty cool. I always have something better to, though.
Can’t go wrong with 180. I recently had a thermostat stuck open for a while and it ran like crap. Got me one of those Robert something or other pricey models, but now running 100% better.
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