It's based on mileage only- you can reset the indicator without changing the oil and watch it go back to 100%. It's really for folks who need a reminder based on the number of miles they've driven. In no way does it actually analyze your oil for deposits/performance.

Either will work. In 2001, GM started recommending 5w30 for the 3800. Earlier 3800s were recommended to use 10w30. There were no changes to the engine or the oiling system. The change to a ligher weight oil was made to reduce the gas mileage (and therefore, emissions) of the 3800 powered vehicles, since a lighter oil tends to increase gas mileage due to less rotating assembly resistance- helped from a marketing and regulation perspective.

 

What's the light supposed to do when it's time to change the oil? Is it supposed to stay on all the time? I bought a 1999 MC Z34 a couple months ago and the change oil soon light comes on at start up and stays on for about a minute, then goes off. When I inquired about my oil light at the chevy dealer, the service advisor said to ignore the light and just change the oil every 3000 miles. Is this why GM is going under? GM spends millions to develop technology that determines the optimal oil change interval, and the dealer says "ignore it". Anyway, I've been going 5,000-6,000 miles on all my vehicles for years with no issues. My 96 Lumina has 197,000 miles now. All on conventional oil.

 

Not really. It's just a timer that goes off every 3000 miles.

 

i had a 99 grand am gt that the oil light would come on every 3k miles. i ignored and reset it by using the reset button in the fuse panel or depressing the gas pedal 3 times with the accessory on. i usually changed oil on that vehicle every 4k to 4.5k with conventional oil. i'm sure the dealer would tell you to get the oil changed every 3k miles (even though it doesn't need it) just so you will bring it in to their dealership and spend your hard earned money more often than you need to. it's all a marketing ploy...when you hear any advertisement on the radio for car care, they always say blah blah 3000 miles blah blah blah.

 

If you read my earlier post, I explained the OLM a little from research i've done, and confirmed with the service advisor at my Chevy dealer.

The older OLM's were based soley on RPM's, and at a certain amount of engine revolutions, the light would come on (what they estimated to be about 3,000 miles worth of revolutions). The new OLM's are much more complex, and accurate in determining oil life.

Sounds to me like the service guy trying to sell you the "ignore the light, come every 3,000 miles" stuff is just trying to be another Jiffy Lube, and sell you on extra oil changes, he sounds like a guy I would not trust to do work on your car.

Your personal 5,000-6,000 rule is about right, I would lean more toward the 5,000 mile mark using conventional oil, and shoot for about 7,500 miles on synthetics.

 

Is the light supposed to remain on continuously when it determines that an oil change is needed? Mine is on at startup for about a minute then goes out. The manual just says something like "the light will come on when a oil change is needed".

 

I think it is normal for it to go out after a while...the one on my 06 comes on for a while, then goes out. But comes back on at start up everytime.

 

If the oil light comes on for a minute, then goes out, does that mean that I need to change the oil, or does the light stay on continuously when an oil change is needed?

 

If its coming on, it needs an oil change. At least thats how it works in my 2006....

In your 99, that is the old style OLM, which is pretty much just an engine revolutions timer, I would just change it every 5ish thousand miles, and reset the light whenever it comes on.

 

Well, since I don't drive the 03 much, I change the oil in that car once a year. I pretty much change the 05's oil every 3000 miles cause of the city driving I do. So no I don't rely on the OMS. When I owned the Mini Cooper S (it used semi synthetic oil), the OMS counts down to when you should get an oil change - @ 10k miles - YIKES - I think that is way too long.