Originally Posted by demarpaint
Originally Posted by earlyre
Originally Posted by demarpaint
"I" found the best thing to do with an OLM is ignore it, opinions vary.
Recently mine would have me changing oil in under 2K miles when driving conditions were exactly the same as they have been for the past 6 or so years. UOA data showed me had I followed the OLM when it was giving more realistic readings the oil would have been in use too long. Get a UOA or two after what you feel is a reasonable OCI based on use, and implement your OCI based on that.
I realize the comments in this tread are all GM, but, my previous Ford,(2009 Mercury Sable) if either a) the car sat, or b) not driven much (I do 10-12 mi a day) the olm would just count down 1% per day.
no matter what setting i put the time or mileage to in the computer w/ forscan, it wanted me to do an oci every 100 days.
I stuck to 6 mos/5k mi, whichever was first, which was usually the 6 months. and went store brand synthetic 9 times out of 10, almost always with a Wix Filter.
Interesting. I don't discriminate, I'd ignore the OLM from every manufacturer. They have merit to people who might not like to pop their hood, keep a log, or have other reasons for not doing routine maintenance. The only rub, is the system better be reasonably accurate, or they'll be wasting oil, or running it way too long. Or maybe they'll get lucky, and it's spot on, maybe. As always, opinions vary.
Originally Posted by jqgz
The science behind the GM OLM was sound. If I recall they put a Corvette on a dyno, fed it heavily filtered air, ran it at 55 mph for like 60k miles on one oil change?
But I would never listen to one. Onstar is like the salty snacks at a bar, tempting you to get thirsty and buy something. Many people would go straight to the dealer if they got a red flag email about the oil being too old. Dealer will see that and talk up the 3,000 mike oil change interval and the overpriced full protection synthetic oil change.
For whatever it's worth, I did an oil change on a Ram 1500 with the 3.6L V6 belonging to a private security firm some months ago; truck had about 29xx miles on it, don't quite remember where the OLM was, but I wanna say between 0-10%. I reset it, and, figuring the thing was gonna be seeing a lot of idle time, wrote a sticker out for 3k miles, and sent it on its way. A month or so later, it came back, with OLM at 0%, with less than 3k miles accumulated (I believe it had 48xx miles at that point).
Originally Posted by javacontour
Does the ECU/OLM even know about calendar time? I was about to say do they know about time, but they do in so much as they time events and run time.
But do they know that you changed your oil on say April 3, 2019 and now that it's April 6, 2020, it's been a year?
I can see OnStar knowing that, but has such "awareness" been programmed into the ECU or OLM?
If the infotainment has a calendar function built into it, I'd be very surprised if the ECM can't see that information, or at the very least, the ECM looks at 24-hour cycles and counts down every day.