GM Owners: GM Oil Life System -vs- Self Directed Mileage for OCI ?

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I'd run a good dino oil (if your OLM is calibrated for that) and then I'd do a UOA at 30% and see how the OLM did. If things looked good in the UOA, I'd leave the oil in run the OLM down to 10% or 5% and do another UOA. If things still looked good, I'd change the oil when the OLM hits 0%.....knowing that the OLM is working right. I'd probably try this with a summer OCI and a winter one, and if the OLM passes these tests, then I'd stick with the same oil and trust the OLM. I'd probably check it with a UOA every second or third year just for fun. Bottom line, find out if it's really works using a UOA, then rely on it if it does.
How do I know if I have a system that allows me to check the % remaining? It's a 2000 Suburban, purchased used, and of course the owner's manual is missing....... (I hate that!)
2000 OLM in trucks and SUV's do not have % remaining. only lights up when a change is needed for a few seconds at start up. to reset, turn the ign key to on, but dont start, and pump the accelerator 3 or 5 times (i cant remember).
I have an OLM in the 98 Grand Prix and the 04 Envoy. The GP usually goes about 6,000 miles or so. It also has a percentage meter too. The Envoy only has a change oil soon light. THe manual says not to change the oil until the light comes on. So, I'm trying to follow that advice. The Envoy has almost 10,000 miles on it since I put in the 7 qts of Mobil 1 5W-30 and the occaisional Lube Control dose. The light still hasn't come on. We are moving to Houston in a few weeks, so I'm going to change that oil before the 1,600 mile drive. I'll be curious about the analysis from Blackstone.
I generally run Mobil 1. On my wife's old Grand Am there was no % on the OLM but it would come on around 5 to 6000 miles. I would change it around 5k usually whenever it would sit still long enough. Got good UOA's. My dad's Caddy displays the % left. On Mobil 1 it got a real good UOA at 30% and about 8000 miles, so the last time we crushed it down to 4% and 11,200 miles. Same filter and no oil added. A Northstar Caddy holds 7.5 quarts btw. Still waiting on the UOA. GM recommends you change the oil once a year even if the OLM doesn't come on.
Is there a listing somewhere of what vehicles have these OLM's? I have a 2002 Cavalier, I'm wondering if it has owners manual came with it....thanks!
Posted by Dominic:
I dont use it because I have no way of knowing what % my oil life is at in my camaro. So, I do a 3k Oil change because I drive 6mi round trip each day to school and back, maybe Ill go on a 10-15mi jaunt if I get a chance. My oil life monitor tends to kick the light on around 5500-6000mi under these conditions which is insane! The range of my monitor is 3000-7500. So I really wonder what on earth I would need to do to make it come on sooner. In my opinon the light is a worst case scenario light.
Have you done any UOA to see whether your opinion of the OLM's performance is as insane as you think? Run a google or two and review the technical stuff written on the OLM. You'll find that it's calibrated to be conservative (set to call for a change earlier than necessary) while using the most average of dino oil. In addition, it's calibrated to the performance of each individual type of engine-car combination. If your's happens to be one that's easy on oil, the OLM's performance will reflect that. You might try this experiment to see for yourself: do a UOA on a sample of oil pulled out at the time when you would normally change it. As long as it's in good shape (I'm betting it will be), press on until the OLM signals for a change and do another UOA (no, I don't mean for you to do this on every change of oil...). The OLM in the 98 Regal GS I owned for a while was one of the things that got me moving away from the silly wastefuleness of the 3/3 OCI. [Cheers!]
Addyguy; I'd bet serious money your car has the light. FWIW you can go to the Helm, Inc website and order an owner's manual!
Just for a comparison of old and new cars. I recently got a 1987 Suzuki Samuari , the label under the hood says to use 5w30 and change at 7500 miles.
The <b><i>car</b></i> companies are being much more reasonable. It's the <b><i>oil</b></i> companies (and Iffy Boob type franchisors) that continue to push the wasteful and silly super short OCIs.
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