GM Truck Club Forum banner

Oil change sensor? [Expired Topic]

3324 Views 3 Replies 4 Participants Last post by  unplugged
So a buddy of mine has an 02 Suburban, and he's noticed something that I thought I would ask about....

Asking about the whole regular oil vs synthetic issue, he mentioned that his Suburban seems to know when his oil needs to be changed.

He said that when he first got it, about every 3k miles the dashboard display would tell him that it was time to change his oil. He figured that it was just an odometer related trigger - every 3k flash the sensor for awhile.

During his last change, he switched to a 7500 mile synthetic oil.

The Suburban FIGURED IT OUT! :shock:
It didn't remind him until right about 7500 miles later that it was time to change the oil again! VERY COOL!

My question is this: How did it know?

Is it reading pressure pre/post filter to determine viscosity, does it have a little optical sensor that can see when the oil is cruddy, or what?

(BTW - He said that the great synthetic oil debate is one that he's watched over on the Camaro forums he frequents, and the only concerns he really found merit with were related to the seals - switching may clean off the residues that are keeping the existing seals sealed. You might wind up with oil leaks you didn't have before, and right after the switch you might have to replace the filter a time or two while gunk broke loose in the engine, but all in all, he liked the idea.

He didn't experience any issues with his switchover which he did at about 85k miles.)

So anyway - how does it know?

Thanks guys -

Tim the technojunkie
Not open for further replies.
1 - 4 of 4 Posts
oil change

He is right about the only issue you will find when changing over to a synthetic is seal leakage.

If he has changed the oil regularly he may not even find that.

As far as how the oil sensor works,

It’s Magic.

Sorry can’t help you not familiar with the system.
RE: oil change

the oil change reminder light works based off of # of times the engine is started, How long the engine is operated for each time it is started, whether or not the coolant comes up to operating temp, average speed while being operated and mileage. if you make lots of short trips, the light comes on sooner because you never warm the engine up to temp which will evaporate any condensation that has settled, you will also have more fuel dillution, because of the rich air/fuel mixture used on a cold engine, which leads to oil breakdown and carbon build up. If you drive across Texas every day the oil light might not come on for over ten thousand miles.
Smart car

I'm just an old desert dog, so I get a little squirrly when a car is smarter than me. My 06 Silverado is always informing me to change the oil at about 3k mile intervals.

Here is how it works:

From the GM website:

GM Oil Life System & Simplified Maintenance
Frequently Asked Questions

* Oil Life Monitoring System
* Simplified Maintenance

Oil Life Monitoring System

How does the system work?
The GMOLS system is not a mileage counter. It is actually a computer based software algorithm that determines when to change oil based on engine operating conditions. There is no actual oil condition sensor. Rather, the computer continuously monitors engine-operating conditions to determine when to change oil. Over the years, millions of test miles have been accumulated to calibrate the system for a variety of vehicles. The system was first introduced in 1988 and is now on more than 18 million GM vehicles.

What makes it so simple?
GM engineers have been studying oil life for decades and they've learned that oil tends to degrade in a predictable pattern. Engine oil forms a coating on the moving parts of the vehicle's engine to protect against friction and heat damage related to combustion. But over time, that protection can be damaged by several factors. High operating temperatures can cause oxidation while cold engine operation introduces contamination to the oil.


As you can see, adding synthetic oil could extend the distance that the oil change indicator.
See less See more
1 - 4 of 4 Posts
Not open for further replies.