Oil Life Monitor system 1996 Fleetwood determining remaining percentage

[cadillacmike68]

These cars don't want to let you know information.

There is no coolant temp, but I figured out how to get that from the Climate Control display diag mode (PCM pointer 24 and it is in degrees C)

There is no DIC like the FWDs of the time.

What - uncle Gerry and aunt Atric can't figure the buttons out?

There is also the oil life monitor but it does not show remaining oil life like the newer triple letter cars (CTS, STS, etc).

It only lights up "Change Oil". I'd like to know what the remaining percentage is. Last thing I want is the change light to come on 100 miles into a 1500 mile trip.

Is there any way to dig that number out of the car's electronics?

It has to be there, otherwise how would it know to light the change indicator.

[Big Fins]

I have that system on both of my daily drivers. Depending on the type of driving and load placed on the engine will dictate when the OLM tells you that you are getting close. I solved the problem by simply doing 5000 mile services. The correct grade of Mobil 1 full synthetic and an OEM filter. Reset the OLM back to 100%.

[TJ Hopland]

Going from likely faulty memory but I'm thinking its RANGE and FUEL USED at the same time?  While it was up was also how you reset it using reset and another button but I don't remember which one.  Been a long time since I messed with one.

The computers fro these were both ahead of their time while being behind at the same time.  The 96 was really odd because it was only year for OBD2 and it doesn't have all the functions we have come to expect from those systems.  I think in many cases the oil life was its own module,  seems like that was something you could get on all the C4 Vettes.       

[Caddyholic]

What does the owners manual say about it?

[cadillacmike68]

The owner's manual states that it calculates the oil life using temperature and revolutions.  It says when the change oil light comes on, you have about 500-600 miles before the oil has reached end of life.

I'd like to dig the actual percentage out of the system, because I know it's there. I like to change when it gets to around 20% on the three-letter cars (STS, CTS, DTS, etc) and they show the percentage, but the RWD Fleetwoods never got any decent DIC because they were planning on shutting the line down for years.

I read up on the GM Oil Life Monitoring system. It's been around since 1988 and is customized for each model that has it and is based on the required oil type (full synthetics for the newer cars, etc.). It's supposedly quite sophisticated and accurate as tested by analysis of used oil samples.

[cadillacmike68]

Going from likely faulty memory but I'm thinking its RANGE and FUEL USED at the same time?  While it was up was also how you reset it using reset and another button but I don't remember which one.  Been a long time since I messed with one.

The computers fro these were both ahead of their time while being behind at the same time.  The 96 was really odd because it was only year for OBD2 and it doesn't have all the functions we have come to expect from those systems.  I think in many cases the oil life was its own module,  seems like that was something you could get on all the C4 Vettes.       

That first part is something to do with fuel economy. The FWDs had DICs back in the 80s. My brother's mid 80s T-bird had a DIC. The computers in 1996 were capable but for reasons known to them (mostly CHEAPSKATES) GM decided to not put a DIC in the Fleetwoods.

[Caddyholic]

I have read that o%. Actually the half life of the oil. 2x safety factor.

[Scot Minesinger]

On my 1995 Fleetwood, I just changed the oil every 3k miles.  I would never rely on a dash light to tell me when to change the oil.  The car still performed flawlessly at 254k miles.  Never suffered a worry with this frequent oil change interval, most driving was highway.

[cadillacmike68]

On my 1995 Fleetwood, I just changed the oil every 3k miles.  I would never rely on a dash light to tell me when to change the oil.  The car still performed flawlessly at 254k miles.  Never suffered a worry with this frequent oil change interval, most driving was highway.

I don't want to change it that often, especially since I switched to full synthetic oil on all the cars.

[The Tassie Devil(le)]

I thought that the idea of Synthetic Oil was to simply change the Filter and leave the oil, but just add sufficient oil to replace what was removed with the filter.

Bruce.

[Big Fins]

I never heard of that Bruce. If that were true, I would simply have just a $40 set of filters changed on my big truck instead of 10 gallons of oil too. The additive package in the oil depletes itself over time, mileage and heat. I have read of tests in, (ugh) Corvettes, where they simply changed the filter and added in the amount of oil lost and it re-boosted the additive package. How true it is or where the documentation is, I don't know.

[cadillacmike68]

If you have an oil burning rat, the above would work, but since none of my cars consume oil excessively, it would not be wise.