I'd like to know what the experts in this community think about the computer suggested oil change intervals. I am an old fart that has dealt with oil changes by mileage. I think that the idea is cool, but it's hard to change old habits. Also, I was told by my dealer that if i used Mobil 1 I didn't need to change the oil for 5,00 miles. That seems a bit long to me, but at $70 per change for Mobil-1 I don't want to do it more then is conservatively prudent. Your thoughts?

George W

 

I, too, come from the old school -- but I've learned to trust the computer. I haven't gone back to do the search, but there's a thread from an ex-GM guy that worked on the development of GM's oil life algorithms. I'm a born skeptic (and former engineer), but I read enough to be convinced; coupled with nothing but good reports from oil monitoring services, I now rely on the DIC oil life % report.

 

The first time in your life that listening to your DIC won't get you in trouble

 

I doubt if you would get a 100,000 mile warranty if Chevy thought the DIC was wrong.

 

 

Yes "learn" to trust it. I too was a skeptic but as others have said reading up and hearing from experts have conviced me to follow the oil life percentage.

While at Carlisle a tech described a customers C5 vette that always followed the percentage, that LS1 had over 200,000 miles on it, they decided to tear into the motor for the heck of it, they found no problems or enhanced engine wear, they described it as looking "like new" inside.

 

good thread

 

Warms my heart to see some more folks coming around on this.



Mobil 1 Test Results
http://neptune.spacebears.com/cars/stories/mobil1.html

"what have we learned so far? Here are a few points to ponder, based on our experience with the Mobil 1 phase.


Getting just one oil analysis only tells a tiny piece of the picture. It essentially would serve only as a pass/fail mechanism; without a trend to monitor, the most interesting parts of the analysis would be impossible to see.
Total base number is a moving target. There are multiple methods for testing it, which makes comparisons between laboratories worthless, and none of the methods have repeatability rates worth getting excited about. While TBN is worth considering as part of the larger picture, as a singular measure it is too flawed to rely on.
Engine wear actually decreases as oil ages. This has also been substantiated in testing conducted by Ford Motor Co. and ConocoPhillips, and reported in SAE Technical Paper 2003-01-3119. What this means is that compulsive oil changers are actually causing more engine wear than the people who let their engine's oil get some age on it.
Topping up the crankcase is a critical component of extended oil change intervals, and frequent filter changes are most likely the key to extreme-length intervals. The cumulative effect of even minor top-ups, let alone a filter change, substantially increases the longevity of the oil.
Based on the results we've got here, we'd recommend 8,000 miles between oil changes on an engine that uses no oil at all, perhaps 10,000 miles on an engine that uses some oil, and 15,000 miles or beyond with a filter change every 5,000 miles. This, of course, isn't any kind of guarantee, and you must evaluate for yourself what your engine requires. One thing we're pretty sure about though: 3,000-mile intervals is a huge waste of resources."


GM Oil Life System & Simplified Maintenance
Frequently Asked Questions
http://www.gm.com/corporate/responsi..._qa_040104.jsp

GM engineers have been studying oil life for decades and they've learned that oil tends to degrade in a predictable pattern.



GM Engineer States that Oil Change Intervals Average 8,500 Miles with Oil Life Monitors...........

http://www.performancemotoroil.com/G..._Monitors.html

Typical drain intervals with General Motors’ Oil Life System, the onboard computer algorithm that tells drivers when it’s time to change their motor oil, are 8,500 miles, versus 5,000 for GM’s competitors, a GM executive told last week’s World Tribology Congress. Drain intervals over 30,000 miles are achievable with minor engine modifications and appropriate oil quality.

“We cannot say exactly when it will happen, but drain intervals will be lengthened,” James A. Spearot, director of GM’s Chemical & Environmental Sciences Laboratory in Warren, Mich



Personal test done by a BMW owner with data sheet...

How often do you change your oil? Maybe too often... | ted serbinski
http://tedserbinski.com/2006/04/03/h...aybe_too_often

"The verdict, for those who don’t care to look at all those numbers: After 15,600 of my abuse, there was nothing wrong with the oil."



NY Taxi experiment........

Consumer Reports Article
The surprising truth about motor oils
July 1996, pp 10-13
http://www.xs11.com/stories/croil96.htm

On the basis of our test results, we think that the commonly recommended 3,000-mile oil-change interval is conservative. For "normal" service, 7,500-mile intervals (or the recommendation in your owner's manual) should be fine.

 

Thamks for all the good imformation

George

 

I agree about following the DIC change interval, but there's one exception. Some of us don't put a lot of miles on the car, and I think it's a bad idea to store it with old oil - so I change it before it gets put away regardless of what the oil life % tells me.

 

I can't even touch that. I am almost to the magic 500 mile mark so this post's timing is perfect. Thanks.

San

 

The manual states to do it at a minimum once a year regardless of what the DIC says.

 

i'm old school all the way, you typically have to lock me down for some change. i was taught in the 60's that you change the oil/filter every 2,500/3000 by my father. i did this without question for decades, believe me. HOWEVER, about 5 years ago i saw the light about this stuff. i have always changed my own oil and now know that with todays oil (reg. or syn.) and filter technology it is a waist of time and money to do it before 5-6,000 miles at the least. i call frequent changes "false piece of mind" but that's just me. the C6 is every 12 months due to lack of use. my avalanche and CTS is dic oil change all the way. take me down to 20-30% just for giggles and i'm ready @ 8-10,000 miles...no sweat. currently the CTS reads 78% and there are 2,200 miles on the oil. i'm going to change it in another 800 miles???? dream on!

 

There is NO reason top change your synthetic oil more often than the DIC indicates. However, I must admit that I still do a very conservative 6K or 6 Month schedule.

 

At what percentage reading on the DIC should the oil be changed then? 50%? 40%? 25%? 20%? or one year, whichever comes first. But still, WHAT IS THE CORRECT PERCENTAGE NUMBER TO GO BY? Does anybody know and why?

 

I believe the check engine light will come on to reminder you to change the oil if you need all this help. Pick a number you feel comfortable with say once a year or when the % gets to say 20% whatever, it is not that much of a difference. I do it on the build date of my vette sort of a birth day present and it is a date I will keep track of untill the next new one.

 

between 10 and 0%. i believe your owners manual states this.

 

Call me hard-headed, but my oil has always, and will always be changed at 2500-3000 miles. I just look at it like going above and beyond

 

It's kind of like using your gas gauge. You don't want to wait until it reads '0', but it's not necessary to fill up when you are at half full. Same goes for the oil change, no need to do it when it says '50%', but if you are getting to the single digits you should get the thing serviced, unless it's been a year in which case you change it regardless.

 

My personal belief is that if you don't drive much (less than 10k/yr), regardless if it's synthetic, every 6 months is for good measure.