: Engine Oil Life WTF?

Unique Distributing
07-26-09, 04:51 AM
So i changed my oil exactly 1000KM ago. I reset it at the time so it said 100% now i just checked it and it is saying 94%
So what does this mean by the time it goes close to 0% (which is when your supposed to change it) says the car. you have gone past like 16000KM? WTF is going on here?

Even tho i dont go by this i usualy change it every 4000KM but shouldnt this be somewhat close to the standard 5000km change point or even a bit over 6-7!! not 16-17000km
Am I crazy or is this something not right about the car. :banghead:

07-26-09, 05:36 AM
Changing your oil is usually a very personal thing, but changing at 4,000 km is in my opinion (especially if you're using synthetic) wasting perfectly good oil. The oil monitor algorithm has been heavily researched by the factory (remember, they're the guys warrantying the engine and are the source for the recommendations for oil change).
Even if your car can be classified under the 'severe use' category, you should be able to get more miles than you currently do before you need to change your oil. A Forum search should yield more insight on this subject.

07-26-09, 08:13 AM
The oil life indicator is not just a mileage based calculation. It also factors in other inputs like driving style & oil sensors (according to other posts around here). In other words, as you drive the car and the oil starts degrading the oil life indicator will accelerate into the lower numbers.

I just ran 7,500 miles between changes (unintentionally, I didn't realize how fast I'm racking up the miles in this joy-to-drive machine) and the oil life indicator was at 35% when I rolled into the dealer. I only noticed because I thought the car started to drag a little more than before when I took my foot off the gas. She feels much better now.

07-26-09, 08:33 AM
Use the proper oil viscosity and proper oil spec from gm and oil filter and you can follow the Oil life monitor until it tells you to do an oil change.

07-26-09, 08:57 AM
Same here.. I get my oild changed at the dealer and I only change the oil when the car tells me or once a year if I go that long. Its certified so I am only following the dealers instructions and they confirmed thats all I need to do is follow the oil index.

07-26-09, 09:41 AM
I change the oil in my STS once a year, as I don't get below 50% on the DIC by that time. I just returned from a 4K mile vacation road trip. I changed the oil just before I left, and I'm currently at 75%.

I've owned several BMW's, and they could easily go 12-15K miles before the DIC said they needed an oil change.

Thunder Gray STS
07-26-09, 11:51 AM
Ok, here's my 2 cents. I had a 1994 Dodge Ram 2500 with the V-10 engine. I bought it used in 1994 with 2300 miles on it. I changed the oil in the truck every 10,000 miles using nothing but Mobile 1 synthetic oil. I sold the truck to one of my customers in 1999 with 234,000 miles on the odometer. I would haul very heavy loads in it, sometimes over 3000 lbs. When you would open the oil fill cap on the valve cover, everything was just as clean and shiney as if it was new. Last time I checked, (about a year ago) he was still driving that truck, and it had around 335,000 miles on it (he pulls a trailer with it). So the 3000 mile, 4000 mile oil change is a bunch of bunk. Maybe 40 years ago it was necessary, but not now.

07-26-09, 04:28 PM
The greatest factor enabling the much longer oil change interval was the almost universal conversion to roller camshafts. This slowed the depletion of the EP(exstreme pressure) portion of the additve package used to prevent rapid wear of conventional flat tappet cam lobe and lifter surfaces. Once the EP additive was exhausted the surface film between cam and lifter was often breached and metal to metal galling would occur resulting in rapid cam lobe/ lifter wear. Oil changes had to be more often to ensure this additve would not be depleted. The roller cam/lifter greatly reduced the demand on the additive making it last longer.

07-26-09, 08:19 PM
I change mine twice a year. Mobil 1 synthetic. My wife always gives me crap because it's $100 bucks every time. The hell with her I say it's worth every penny. Just wish I had the equipment to do changes myself.