Oil Life Monitor in GM Trucks

My new to me 2002 Suburban has a feature that claims to calculate oil life based on revs and some other magic. According to the manual, it will light up for oil service when needed, and you are supposed to change the oil within two tanks of gas when the light goes on. If there is a way to see what the status of the oil is before that light goes on, I haven't figured it out.

Anybody have a truck with this feature and rely on it? I'm curious what kind of interval it will indicate. I'll probably just go with 5k intervals unless the light goes on first.

If you use the steering wheel buttons the oil life % will show in the information display at the base of the speedo. I'm using it on my 03 Suburban 2500 this time, then sending the oil in for analysis to see if I can trust it. I do run synthetic oil though, so have less concern about stretching the interval.

From what I understand, its pretty accurate. It of course doesn't actually test the oil, it just makes predictions based on thousands of inputs; percentage of time at steady-state vs accel/decel, average coolant and oil temps per mile, throttle position maps, intake air temps... its pretty comprehensive.

It does not, however, take into consideration dusty conditions vs not, humid conditions vs not, whether you're using Royal Purple or generic oil, using a Fram filter or a Purolator...

I use the one in mine as a guide, but I stretch it a bit with better-than OEM quality lubrication parts. My diesel, however, gets oil every 3000-4000.

depends on the truck. My father's truck has the OLM that shows you what percentage you're at. Our truck only comes on when it's time. I think it depended on the options package the truck had.

I had an Escalade (god help me) that had this feature. I thought it was a neat trick, sort of like the BMW service countdown, but I never put a whole lot of faith into it. Or really, any faith into that heap.

Our '01 Burban has one and I ignore it completely. Since we have a lot of short trips I change the oil much more frequently than I would if I were to use the life indicator as a guide. I'd rather change it too often than not often enough.

When I'm doing more short trips it counts down faster than when I'm doing long trips. I think they use a pretty comprehensive set of code honestly. I use Mobil 1 and I follow what the meter says. I've just started using Blackstone for oil analysis with my other cars, so I'll let you know what they say about the truck at then next oil change at about 100k.

I ignored mine the first few times as it was stretching OCI's out to 8-9k miles. I was changing every 5. After I swapped to M1, I started following it. Oil test came back at 70k perfect so I am not worried about it.

I was told that these are often based on fuel usage. Makes sense, really - if you're working the truck hard, you're using more fuel. So it basically assumes you need a new sumpful of oil every X gallons. Simple.

I rely on it with my Cummins. It doesn't do a lot of short trips, but it does work hard when it's out. The one in the BMW is stuck, it hasn't moved since I bought the car.

I bought a new Silverado last year & have used Blackstone tests to try to confirm the accuracy of the OLM. After an initial change about 2000 miles in to Mobil 1, I next changed the oil when the monitor suggested it at roughly 7500 miles. The Blackstone test confirmed that the oil was still in great condition & they suggested going about 8500 miles before the next change. Again, the OLM suggested a change right about 7500 miles, which makes a lot of sense as my driving is very consistent, about 80% highway. I am awaiting the test results on the oil from the 8500 mile change & can certainly update this thread at that time if you all are interested.

In reply to FooBag:

I'm a regular lurker over at BITOG so I'm interested.

At the risk of turning this into an oil debate I run Pennzoil HM in our "fleet".

curtis73 wrote: From what I understand, its pretty accurate. It of course doesn't actually test the oil, it just makes predictions based on thousands of inputs; percentage of time at steady-state vs accel/decel, average coolant and oil temps per mile, throttle position maps, intake air temps... its pretty comprehensive. It does not, however, take into consideration dusty conditions vs not, humid conditions vs not, whether you're using Royal Purple or generic oil, using a Fram filter or a Purolator...

This.

The OEM-spec oils on oil life monitored systems are often rather high spec. I know Motorcraft oil is actually a really, really good semi-synthetic for its price point. Not sure what GM specs other than dexos1/2 for the newer stuff.

The oil life monitor is also not assuming that you're getting dirt into the engine from a misaligned air filter or small vacuum leak or other such issues. It also assumes that you're going to be a good little consumer and get a new car after 3-5 years.

I let the OLM get to about 20% left and start gathering up the oil and filter to change it out. I get about a 6k interval on the Av and 4-5k on the losing oil Imp. I was putting in G-Oil and Napa Gold PF61 equivalent filter on both vehicles, but the G-Oil is NLA around here. Back to Mobil 1, since it also had a price drop at WhiteTrashMart, I guess.

Keith Tanner wrote: I was told that these are often based on fuel usage. Makes sense, really - if you're working the truck hard, you're using more fuel. So it basically assumes you need a new sumpful of oil every X gallons. Simple.

I may be misunderstanding what you are saying (and we might be agreeing), but typically a major issue in new cars today if oil changes are done at proper intervals is simply the oil getting contaminated by fuel (or in diesels, soot).

Having said all of that, if anyone has read BobIsTheOilGuy, they drove a brand new 2002 Camaro SS using Mobil 1 synthetic for tons of miles. By 20,000 miles it required an oil change due to analysis.

Therefore, I use the best synthetic I know of (Shell Rotella T6 5w40) in all my vehicles (turbocharged or otherwise) and do oil changes every 20,000kms on the cars, 15,000kms on the truck (which is only used for towing).

The racecar? Oil changed every 2 regionals or 1 national. If I can get them, either OEM filters (for Subaru) or purolator filters (everything else).

The oil life monitor on my 2002 Silverado 2500HD is a simple mile-based one, it goes off every 10K miles no matter how you drive. Mine's the Duramax, though, so the gas engine trucks might have a different one.

I have been relying solely on the OLM since 2006. In my Canyon, I drove predominantly highway, and it would regularly see 20,000 km between changes. I checked with the dealer at about 12,000 to see if this was normal and they assured me it was. The wife's Cobalt hits it at about 12,000 km every time.

Knurled wrote: The OEM-spec oils on oil life monitored systems are often rather high spec. I know Motorcraft oil is actually a really, really good semi-synthetic for its price point. Not sure what GM specs other than dexos1/2 for the newer stuff.

You want specific oils, go German. They have completely lost their minds on some applications, and their change interval can be painful. So, whats that you say? I'm supposed to change the oil every 25,000 miles, but I don't have a dipstick to see if there is any? I would have trusted the electronic oil level monitor, but since its electric and German, it doesn't actually work...

My guess is that they go off resistance- if your engine is making metal, it will have lower resistance and trigger.

Streetwiseguy wrote:

Knurled wrote: The OEM-spec oils on oil life monitored systems are often rather high spec. I know Motorcraft oil is actually a really, really good semi-synthetic for its price point. Not sure what GM specs other than dexos1/2 for the newer stuff.

You want specific oils, go German. They have completely lost their minds on some applications, and their change interval can be painful. So, whats that you say? I'm supposed to change the oil every 25,000 miles, but I don't have a dipstick to see if there is any? I would have trusted the electronic oil level monitor, but since its electric and German, it doesn't actually work...

We use Agip. 99% of the special applications in one oil. Love the stuff.

The trick with Mercedes is that you have to wait something like 15 minutes after the last time the engine ran, then turn the key on and find the menu in the maddening DIC before starting the engine.

Teh E36 M3 wrote: My guess is that they go off resistance- if your engine is making metal, it will have lower resistance and trigger.

Strictly inferred values based on run time/average load/temperatures/etc.

Fastest way to make the oil life monitor drop to zero is to get the engine hot. As in, unplug the fans and sit in traffic and wait long enough for the engine to go into bank-switching mode... happens around 260-270F or so.

Ford says to run my Fiesta 10K miles or 1 year, which I have been doing. Not too far from the 8-9K miles I have been doing on all of my earlier vehicles. I started this back in 1994.

I use Amsoil.

The GM OLM has 30 years of research behind it. Life is taken out based on your driving routine, the predicted temperature of the oil due to that driving, and other factors that are detrimental to the oil. It is conservative and it varies based on the engine configuration. The owner must check the oil level.

Teh E36 M3 wrote: My guess is that they go off resistance- if your engine is making metal, it will have lower resistance and trigger.

There is zero oil "testing" involved. It is strictly computer input.

If there is enough metal in your oil to make continuity at all, you have long-surpassed any hope of saving the engine.

put it in tow/haul mode and watch it drop like a rock.