V6 Tow Package mandatory TRD Off Road?

Quite conversely actually, the first law of thermodynamics (with reference flow of heat/heat transfer) says (basically) that heat will always flow or transfer to a colder body. In a cold environment the coolant (should it warm faster than the oil) will actually warm the oil. Conversely should the oil, via circulation through the engine, actually get warmer than the coolant, then the flow of heat will "reverse" and the coolant will act to reduce the temperature. There will be an attempt to bring "thermodynamic equilibrium" between the two fluids. (It's actually much more complex of course.) Basic convection at work inside the oil cooler that allows hear to flow between the two fluids.

 

It is exactly that tendency toward thermodynamic equilibrium between coolant and oil that I wonder about. If I'm not mistaken, in winter the temperature of the coolant coming from the radiator is far below the ideal lubricating temperature of the oil. If the oil cooler is using coolant directly from the radiator for heat exchange, this would work to keep the oil too cool in winter.

Here are a couple of random quotes from internet sources concerning the need for thermostats in oil coolers to prevent overcooling of oil.

PAT GOSS: "And for those of you who don’t know why this is so important, oil gets moisture in it and that moisture continually builds up unless the oil temperature reaches at least 212 degrees to boil the water out of the oil.

LYNDEN ABEL: Quite right and that’s why it’s important to get a quality oil cooler that‘s designed for your vehicle that had a thermostat in it. This is again the same example of a Harley Davidson oil cooler and this has a thermostat inside it, which does two things, one it doesn’t overcool the oil. So if you’re out in the winter time riding around it’s not keeping that oil you know below 200 degrees, its not allowing it enough to boil off that moisture. But also it allows the oil, even in summer time, to come up to temperature more quickly because its just circulated through the engine til it comes up to proper operating temperature and then it’s allowed to do what it needs to do."



To alleviate the creation of excessive moisture, the optimal operating range of engine oil is no less than 212 degrees, which is the point at which the water in the oil will evaporate. Vehicles with an oil temperature thermostat (which we’re going to discuss here shortly) are typically set right at or slightly above this mark. Conversely, you don’t want to run the oil above roughly 240 degrees, as Speed tells us, because you begin to significantly reduce the life and operating ability of the oil, as oil containing moisture doesn’t flow or lubricate properly. In a high performance engine with high dollar parts with tight clearances running at above-cruising-speed RPM’s, this is vitally important.


This is the complete setup that we’re installing on our Project Biting The Bullitt Mustang, including Canton’s thermostat, oil cooler, and sandwich plate, along with all of the plumbing hardware from Fragola.

This is where the aforementioned thermostat and the use of oil coolers come into play, and we’ve outfitted our Mustang with a setup from Canton that’s sole purpose is to keep the oil within this window of operating temperatures through a bevy of different driving environments.

 

Do you think the oil is not going to reach 212 when it comes out of the cam in the head? It roasts up there in the head and there is no coolant up there. It will definitely boil water off up in the head

 

I don't know if that is correct or not. But it doesn't seem to be the opinion of those I quoted who think it is important to have thermostats on oil coolers to prevent overcooling of oil, at least in winter.

My own guess is that the oil is moving too fast within a running engine to reach the temperature of the hottest surfaces. I would think that the turbulence would tend to equalize the oil temperature to an average.

 

I don't think so. Oil sticks to surfaces. It's made to do that. It's roasting up there in the heads.

Why is a small amount of water in the oil bad? With all the agitation they are speaking of, the water doesn't need to be 212 to turn to steam and escape the engine block. Also, if it does, it's going to PCV back into the intake tract and be burned with the fuel mixture.

 

I think we are getting into questions that it would take an expert to answer. I do know from physics 101 that water under one atmosphere of pressure won't boil until it reaches 212 degrees, though the turbulence of oil within a running engine might increase the water's evaporation (as distinct from its boiling). But I would expect that most of what evaporates would condense back to liquid water in the cooler parts of the engine.

Aside from the issue of water in the oil, there is the point of keeping the oil within the optimal temperature range wherein it lubricates most effectively (see above quotes and link).