oil monitor accurate?

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Aug 9, 2002
It's actually not too bad of a device, I had one in my 97 GTP and it showed a countdown in
the trip computer to % of oil life left. I found that when I changed my oil (in 5k intervals) that
the computer would show about 30% oil life left.

It's good because the more cold starts you do, the quicker the percentage drops, and same
with hard driving. If you do mostly highway, it drops slower. So it does give a decent
representation of the conditions the oil is seeing and adjusts the oil change interval
accordingly. I wish my 95 Firebird had this same monitor, it was a neat gadget! (I also miss
my average MPG monitor on that trip computer!!)
There was an article on it a couple of months ago in Lubes'n Greases magazine. I don't remember if it's the one you have to reset when you change your oil, nor do I know if it then looks at the actual oil or an imaginary standard and sets it's expected limits, but it monitors the dielectric change in the oil to determine how degraded it is.
It seems to work okay although I use it only as something to check once in a while. I am on a 12,000 mile change interval with a filter at 6000 so when I do the filter I just reset the monitor. At 6000 miles though it has anywhere from 25-30% left but I do about 60% interstate driving. This is a 00 Buick Regal GSE
Did some research on this oil monitor and IMHO it is a good tool.

It counts down based on engine speed (RPM).

It also monitors engine tempature.

RPM at a fast rate, hot engine, and cold engine all make the countdown go quicker.

GM has a couple of informational papers on the web but I can't remember how to find them.

If you use a synthetic oil where none is specified (non-corvette) the monitor is way too conservative. It doesn't know the type of oil or monitor the condition of the oil.

You may also find that good Dinos can go much farther than one countdown cycle.

Oil analysis, $15-25, will tell you for sure
My wife drives a 98 Grand Prix with the oil life monitor. I used to go by it for oil changes, but don't anymore. The highest milage it was drove on an oil change was, 7,400 miles with 3% oil life left and this was using 10W-30 Mobil 1. I have almost 5,000 miles on the 10W-30 Mobil 1 and the percentage of life left is 34%. I plan on doing an oil analysis at 5,000 miles to see how the Mobil 1 holds up in this car.

I should mention that GM has a TSB out on how to clean sludge out of the NorthStar engine.

Is that related to use of the oil change monitor using SJ oil?

With Europe, and South Africa so I hear, using longer drain intervals, the use of an engine cleaner seems more important now.

Maybe that's why that mechanic in Liverpool would like to give Auto-Rx his first born.
There is a Caveat to the oil "monitor." It does not actually monitor the oil itself, so it is possible to trick it. The monitor works by counting the mileage and weighting it against operating parameters. The primary parameter it measures, after mileage, is wheather the engine is in open loop or closed loop. If the engine were to spend the majority of it's time in closed loop, it will take you to the max interval. Each mile in open loop will send you toward a minimum, and if it is 100% open loop, you would not make it to 3k.

The main thing that will fool it into giving you too long of an interval is dusty conditions. It has no way of monitoring for oil contaminents.

That is one thing I look forward to in the Bosch oil monitor, which actually monitors the oil, not the conditions.

As has been said above, the monitor is set up for an oil meeting the minimum requirements for the engine. This would be an SG 5W30 in the case of my car. So any better oil will go further than the monitor indicates.
I would bet that either towing or heavy hauling also qualify for severe service, and qualify for the 3K change. I am using the monitor on my 02 Silvo but have changed to M1 oil. RW

Originally posted by satterfi:
Here's another definition of severe service from the 'Filter Manufacturers Council'.
severe driving

It doesn't make sense about the severe service. If a majority of the people (about 80% according to their stupid survey) are using their vehicles in severe service, why would the automobile manufacturese designate that as normal. The have a different catagory like exception service, or easy service whereas they would like those 20% of the folks in a special catagory.

If you note who endorses it, you will see API, heck yes they would endorse it, don't they want to sell more oil?? Arent' they made up of the large petroleum producers??

If you want my opinion it was a stupid TSP. Follow your owners Manual.

BTW, wouldn't the European manufactures consider most of the cars over there servere service?? Blasting down the Auto Bahn at 130 mph, or stop and go traffice( there are over 2 times as many people in Europe per sq. mile than over here!!

You want to talk about traffic Jam?? They call it a Stowe. ( I've been in a few, they are the mother of all traffic jams!!!)
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