Change Oil Light?

Tweeter400 · May 12, 2003

How does it figure when you need to change your oil?? Miles/Hours?

cowboy02 · May 12, 2003

Did Bill Gates design this system??

It seems that he is the only one that would care that your oil get's changed or not...

SilveradoWV · May 12, 2003

It doesnt really analyze the oil, if thats what you are wondering, you can tell because you still have to reset it with clean oil . I think its based on RPMs and hours or something. Its kind of like a clock IMO (useless).

Shaners · May 12, 2003

I believe it is a mathematical algorithm that works on miles/hours/RPM's/engine temps etc....

Quite awhile back there was a link posted to an article on here, that explained how it all worked and some tests were run on oils that were changed out due to the light... some were only about 2500 miles of severe driving versus 6000 miles of highway driving, and surprisingly the oils were very close to the same condition.

The system doesn't actually touch or test the oil itself, but based on mathmatics, it seems to be pretty good.

My light comes on between 2500-3500 miles, and I change it when it comes on.

Greg · May 13, 2003

I drive lots of highway miles and change the oil (synthetic) every 5K and the light never turns on (if I remember to reset it). If I forget to reset it, it turns on at about 6-7K.

canadianchevy33 · May 13, 2003

I beleive it uses a system of engine hours/rpm and operating temperature. I think it has a preset table inside it to monitir all these things. It also takes into effect when your vehicle is started cold or hot.

Charlie in TX · May 13, 2003

It seems to work fairly well. My '99 GMC 1500 would usually come on at 5200 - 5500 miles. When I drove more in the city it went down to 3500. My '03 GMC 2500 is only on it's second oil change. The first said to change it at 6500 miles (mostly hwy miles).

Think of it operating like this. You change your oil and reset the oil monitor. Under ideal conditions this give you say 12,000,000 revolutions of your engine (thats 2000rpm @ 60mph for 6000 miles) (the number will be different for different type engines). Under ideal conditions 1 revolution of the motor takes one from the 12,000,000 revolution 'bank'. Under less then idea conditions, like cold start, 1 revolution of the engine will take more than 1 from the 'bank'. Further, if you are driving with a load on the motor more than 1 removed from 'bank'.

One of the drawbacks of this system. It can't protect the engine if inferior oil or oil filter is used.

If you can't tell. I go by and trust the oil monitor system.

bigmack · May 14, 2003

Technology is only as good as the operator.

Used a different work truck a few months ago. Started it up and the oil change light went on, and as you all know it turns after about 30 secs.

Returned the truck and commented that the light went on. He told me not to sweat it as it has been doing it "for a while" but it turn off once the truck warms up, no problems. The 3 of us around him were doubled over in laughter as he continued to look confused. You gotta feel sorry for the truck and wonder how full the pampers on his kid must be. He crys for a while then stops.

Man we all must come across stories like that every day. May be worth a post in the general section.

maggot · May 15, 2003

Here is GM's answer. I still go 3000 miles myself but for what it is worth. I think it is stupid myself. Something to jack the price up. My opinion is get you lazy but under your truck and chjange your oil and lube the dang thing.

How often should engine oil be changed?

- 3,000 miles (5000 km)

- 5,000 miles (8000 km)

- 7,500 miles (12000 km)

- 10,000 miles (16000 km)

Actually, all of these are correct, depending on operating conditions. Oil life is affected by many factors other than just miles driven. The type of driving, temperature, and engine load all play a part.

That’s why GM has developed the GM Oil Life System, an electronic watchdog that keeps track of all these variables and notifies the driver when it’s time to change oil. (fig. 1) We first told you about the GM Oil Life System in the March 2000 TechLink. Since then, the system has become standard equipment on nearly all GM products.

Briefly, the Oil Life System is programmed with a certain number of engine revolutions. As the engine runs, this number is reduced until it reaches zero, and the Oil Life light or message comes on. But there’s more. Operating the engine under low or high temperatures, and under high load conditions subtracts (penalizes) extra revolutions, so the light comes on sooner.

Changing engine oil according to actual need rather than an inflexible schedule provides several benefits.

First is simpified determination about when to change oil. No more decisions about “normal” conditions vs. “severe” conditions. Second is reduced operating costs for GM’s customers, who now have to change oil only when it’s needed. Third is minimizing the amount of used oil that must be disposed of. And fourth, engines will always be running with sufficiently fresh oil, for long life.

These benefits will be realized only if engine oil is actually changed as indicated by the GM Oil Life System.

Some customers “get it” when it’s explained to them. Others may be reluctant to deviate from traditional oil change interval charts. So, part of the responsibility falls on retail service people to help get the message out.

TIP: To help you do this, an IDL broadcast is being prepared. Consult the GM Training Program Guide and Schedule for “Understanding the GM Oil Life System” (PPS03.P1D).

There’s More

Traditionally, the vehicle maintenance schedule has been based on miles or time, while the oil change interval is now based on the GM Oil Life System. This could result in customers having to bring their vehicles in for an oil change when the light comes on, only to find that the vehicle is due in a month for scheduled maintenance.

That’s all changing. In the accompanying article “Simplified Maintenance Schedules”, you’ll learn how maintenance intervals are now being tied into the oil change intervals indicated by the Oil Life System.

- Thanks to Jerry Garfield and Chuck Burns

GnatGoSplat · May 15, 2003

GM has had the Oil Life Monitor system in some GM cars for quite awhile.

I have it in my '89 Cutlass, and I followed it religously. The car currently has 198,000 miles with 100% original engine parts and compression is still perfect.

I trust the Oil Life Monitor.

CapnDean · May 15, 2003

WOW! Who woulda thunk it?

I have always done the 3K deal. In fact, if the odometer reading is a multiple of 3000...That's when I change my oil. That's the way I have kept up with it. Having read this....I am going to change it when it hits 30K, reset the oil life indicator and then go from there using the high dollar technology that I have paid for!

Thanks for a wisening article!