Oil Life Monitors and Extended Performance oil

[gfh77665]

Originally Posted By: Gary Allan

So this (essentially) makes up your 10k/year OCI (close enough)? I'd probably go to a cheaper product and follow the OLM.


My truck is almost 100% highway driven, and out of warrenty with 160,000 miles. Since I rack up over 20K miles a year, I like only having to change twice yearly. I would think 10K intervals
are very safe with a 15K guaranteed oil. Works well so far..

 

[zulu]

It uses ambient air temperature, but only to gauge oil operating temperature vs. engine duty cycles. But taking outside air temperature (plus coolant temp) and comparing how many cycles the engine has made and at what % load, it tries to guess the estimated oil temperature. The oil temperature is what directly affects the "slope" of the oil degredation algortithm. It also uses OATs for caculation of cold soak times. All this is in an attempt to acurately model the rise and fall of oil temperature, because that is the single most important figure to accuratly modeling oil degredation. It knows that if you sit for 8 hours a 32 degrees, the oil temperature is 32 degrees (cross checked by coolant temp), but if you run your car up to operating temperature while it's 32 degrees outside, and then turn if off for 5 minutes and restart, it is able to calculate the new soak temperature. Again, all this effects the "slope" of the algorithm. There is tons more info all around the net if you google "GM Oil Life Monitor"

 

[dwendt44]

The engine, and maybe the oil temp. are certainly part of the calculation.
During winter, the engine and the oil take a lot longer to get to temperature, so that right there would shorten the oil change interval figures.

 

[Gary Allan]

Here's an excellent post telling all about the OLM by a GM power train team member.

https://bobistheoilguy.com/forums/posts/130107/