Oil cooler question

[cycleguy55]

Originally Posted by patrickt

I have an oil cooler, with no thermostatic valve on it. My oil temp tends to track with coolant temp, generally around 185 degrees in the summer, and it doesn't get driven in the winter. I recently posted a thread on my oil analysis after having the car sit for four months and the oil having not been changed in four years. There wasn't a molecule of moisture that showed up and the oil temperature articles that aren't "shooting from the hip" peg the temperature for the least amount of engine wear at the low 180's. Here are two typical articles of that ilk: The heat is on: Our experts agree on the best oil temperature and Elephant Racing | Tech Topic | Oil Temperature and Engine Life and there are many others.

Consistent with your comments, this link (Performance Unlimited 4-Wheel & Off Road Center - Hartford, Wisconsin - USA Technical Documents) shows optimum oil pan temperatures in the range of 175°-195° F. It also shows how bearing temperatures are typically 75° F or higher than oil in the pan, and it's the bearings we're really trying to protect.

This article (5 Things You Should Know About Motor Oil | Driven Racing Oil) recommends oil sump temperatures between 180° and 220° in order to drive out moisture and keep the oil dry.

This is a good article (http://www.wearcheck.co.za/downloads...tin/tech43.pdf) that covers a broad range of topics relating to oil, including temperature, viscosity, lubrication, etc..

The consensus certainly seems to be that optimum oil pan / sump temperature is in the range of 185°F +/- 10°F. OTOH, this article (http://towprofessional.com/article/s...-vs-petroleum/) shows the temperature limits of synthetic are considerably different than petroleum oils, with higher limits for synthetics (which is what I'm running).