That being said--I noticed only about a 5 degree drop in my
oil temp despite the change to the 160 thermo for the coolant. So it may depend upon the engine and setup. I'm not sure there is a direct correlation between coolant and
oil temps--yes, they affect each other, but certainly not degree for degree.
No question that too cool a temp, or too hot, can affect engine wear. Coming from a farm--alot of idling, heavy loads, working in extreme heat and cold--I know this to be true. But where are those limits and how do they apply to particular motors?
For example, is my Cleveland (10.5 to 1, lumpy cam, etc.) going to be affected the same way as a Windsor? Or an FE? I do know modern cars, electronically controlled (to prevent detonation) as they are, are designed to run at hotter temps (using
synthetic oils to allow for it) for smog purposes as much as anything else. Having used my 92 Vette in the California desert for business purposes (drive, park, go, idle, etc.), I certainly got to expect 220-235 as "normal". This was with the LT1 motor with reverse coolant flow which was created to get the coolest coolant to the heads first--why?
Maybe the 60s/pre-smog motors can benefit from a 20 degree coolant drop while it may not be a good idea for Windsors or other modern motors. Again, with a 160 thermo, my motor does not run at 160--it runs at 170-175--is there going to be damage? I have to wonder since
synthetic oils were first created for military use to deal with freezing temperatures as much as extreme heat.
Alot of conflicts in information--anybody got some answers?