oKLRider said:
Interesting. I've been experiencing similar the last few days. Didn't really worry about it until the oil light came on...twice. :-[
I always let it warm up before rolling out. The last couple of times it happened I left out when temp was ~125°F. No hard accels, in the cold, until temps rise. Around 30mph or so, the light came on. Pulled over quickly. Engine off. Restart. Light goes away. Let the temp rise some more, and head out. No more light.
Thought the first time was a fluke. Second time, guess not. Let it warm a little more, no problems, even with heavy revs. Cruising on the highway the temp stays around 160°F, best I remember. I'll watch it closer tomorrow. Warmer weather it consistently hovers around 173°F. For comparison its been in the mid 20s the last few nights on the way home, and I'm running Rotella 5w-40 T6 synthetic.
OIL THREAD!!!
Remember that the oil is essentially has to move to/from a separate reservoir, so it is not always where the engine is directly making heat.
Until the oil is really warm it will continue to try to squeeze through passages with the thickness/viscosity it has at low temperatures. I book marked a page that has a great discussion about this and it is at:
http://www.kewengineering.co.uk/Auto_oils/oil_viscosity_explained.htm
The idea of 5/40 is that the oil will perform like a 5W oil at freezing (0C) and no thinner than a 40W oil at 100C.
See the line that says "too thin?" There should be another flat line just above where the dashed line crosses SAE 5, and that second flat line would be labeled "too thick." Imagine for example if my new horizontal "too thick" line were at 200 cSt. Because the multi weight really isn't a nice flat line, when colder than freezing the oil performance can still cross the "too thick" line and not be able to go through pipes and passages. The engine can starve for lubrication.
And remember that as pretty as the chart above is, the change in viscosity really looks like this over a range of temperatures:
So a little colder or warmer is disproportionate to a BIG change in how thick the oil is when it is even approaching freezing and not really that cold!
Because the Tenere oil light really is just letting you know the oil tank is low, it is implying that the oil is elsewhere. Engine designers know that hot oil is thinner and will make return passages narrower. So an engine with a cold thicker oil can have the oil level increase drastically in the crankcase, rather than circulate it back to the tank. At idle and the lower revs of starting out, we shouldn't be doing engine damage, but I wouldn't want to rev it to the red line. So don't worry unless you are racing streetlights straight out of the garage when it's that cold.
Which is why a good long warmup is pretty important in any motor with a remote sump when the temps drop below freezing.
