Quote:
Originally Posted by aerobod
The temperature that the oil is at is not directly related to how it is protecting the engine. What is important is that all the engine components are heated up to the point that they are at their optimum design clearances and the oil is at the optimum viscosity between the moving parts. The oil temperature is a much better reflection of this stable state being reached than any other easily measurable parameter.
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That's what I've been saying, except, I disagree that the oil temp is the better indicator of that. The parts have reached the engine operating temp by the time the thermostat opens, that's the reason why it stays closed until that time, so that engine temp can be reached faster.
By the time the oil absorbs enough heat to get it to this magical 240F, the engine is well into being warmed.
The engine/coolant temp is the better indicator, but we don't have one, and that sucks.
You seem to understand, better, the issue of warmed up engine components better than some of the posters who think that they are hurting their engine if they drive it before their oil gauge reaches that certain temp.
There is NO indication on the oil temp gauge that says, "ok, now you can open it up." Nor is there any indication that you shouldn't open it up before it reaches a certain temp. In fact, there is NOTHING on that oil temp gauge except some numbers. If the oil temp gauge were showing a certain driving condition, then there should be a red, yellow, green, yellow, then red indication, showing where this optimal temp level is, but there isn't. The question is why? It's because the oil takes a good deal longer to heat up than the surrounding parts. Part of the oils job is cooling, most of it's job is lubricating.
I agree it's important for the engine bits to warm. However, it seems we disagree when that is. I've always used the engine/coolant temp as the indicator, and it's a shame BMW didn't leave one on. I've used the engine/coolant temp gauge as the indicator since I began driving in 1981, and it's never failed me or my engines.
The oil temp gauge is an ancillary gauge especially important when running hard mainly on the track. I don't know why BMW thought this was THE guage to have, because frankly I would have rather had an oil pressure gauge along with a coolant/engine temp gauge
I keep reading these oil temp gauge threads and a lot of people are stuck on using it as an indication of when to open it up. It's not the gauge of when the engine is warm. If anything, it's a gauge of when the engine temp has gotten so high that it now needs to open it's thermostat to try and REMOVE the heat. The coolant thermostat opens probably at around 170F, or when there is sufficient heat build up for proper engine operation, and now it's time to start proving cooling. The thermostat opens to circulate the coolant into the radiator to COOL it down to help maintain the best engine temp operating temp.
There are people on here who think their oil is somehow not protecting their engine whirly bits until it gets to around 240F. That's not ture.
Hotter oil is not better are lubricating than warm oil. In fact, if the oil gets too hot it starts losing it's lubricating properties.
The logic of it is getting lost with this oil temp gauge discussion.