Can anyone shed some light on the new engine monitors that GM has in their vehicles that tells you when to change your oil? If I listened to this thing, it would have been close to 10,000 miles before it recommended to replace the oil. Anyone know how it decides that it is time?

The dealer says that synthetic oil is totally unnecessary in my 08 suburban. Maybe... 10,000 with synthetic?

Then you have the quickie oil change places that still recommend replacing oil every 3000 miles (of course they would, why wouldnt they?).

Who has the truth?

Click and Clack on Car Talk say 5,000 miles under normal conditions, with the explanation that oils are much better than 20-40 years ago. 3,000 miles is from your grandpa's days.

Go with what your owner's manual says if you want to feel safe.

Thats the problem, the owners manual says to follow the computer display and that seems to be on a 10,000 mile cycle. Sounds too high to me.

Then go with 5,000 miles for peace of mind. It can't hurt.

I have seen cars go up to 12k miles before the indicator comes on. That is crazy! I have a ton of customers who go over on mileage just do to lazyness. Keep the 3000 miles mark for oil changes on conventional oil, due to the fact most are going to go over on mileage. If the industry starts saying go every 5000, then people will start going even further over that. Which is a bad habbit to get into. Leads to carbon buildup, sludge and abnormal wear. Long story short I have replaced several motors for lack of changing oil regularly.

My owner�s manual says 5000 miles but I am old school so I just split the difference and change my oil at 4000 miles. it may be over kill since I use FOMCO synthetic blend oil 5W20 but it makes me more comfortable doing it that way

The computer on my 4.8 chevey tells me to change it every 7000 to 7500 miles. 120,000 no problems.

I was told by a chevy mechanic, (one that I trust totally) that the system was based on the run time, not mileage.. Something like an oven timer. "X" number hours that the engine runs, equals approximately "X" miles. But however it is based, 3000 miles for me, WHY?,,,oil is cheep compaired to an engine.

This article is about 10 years old but still has valid information...it is from Consumer Reports...one of the issues for me with changing the oil more frequent than needed is the extra waste oil generated in the enviorment..and the need to import more oil when maybe it is really needed..People worry about gasoline mpg...I look at motor oil the same way...just my 2 cents worth. Consumer report artile is in the link below..

http://www.moneybluebook.com/articles/consumerreports.oilchange.php

i just cant see changing it 7 to 12k miles, seems to long.

5K or less with a quality conventional motor oil

I do 6K then that reminds me to rotate tires too

If you use fully synthetic and drive mostly highway, then 7500-10K isn't unheard of and quite acheivable. I have an '08 Silverado with the 5.3 and I change mine every 5K regardless of what the monitor tells me. I only use Mobil 1 Synthetic and I drive my truck pretty hard and the oil still looks pretty good when I drain it.

Heres an idea if you want to see how accurate that is. There are companys that test oil samples. Its not that expensive to do. They will annylize the oil showing all the components present in it and give you a recommendation of whether you should change your oil your filter or both. Reason I know this is I am looking at getting the amsoil filtration system for my diesel and you send oil samples in to this company every 15k miles and they give you that data. It cost $25 dollars and typically only take a few days. would be a good little experiment to do on your vehicle one time to know if the advisor is right.

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