Oil Life?

**muffinman** · 08-09-2007, 07:39 PM

How does the computer in my 04 suburban know when the oil life has expired? The manual does say it has a sensor that reads different things but i'm curious about if it measures viscosity.

**dwill3015** · 08-09-2007, 08:47 PM

Welcome to the site!

GM Oil Life System analyzes the engine's operational data including temperature, revolutions, speed, to calculate the rate of engine oil degradation and determine when an oil is nearing the end of its life. At this point a message on the dashboard signals that it is time to change oil.

Each OLS computer model is engine-specific because GM believes each engine behaves differently under the various driving situations and conditions. For this reason GM is on record as stating there can be no standard oil change interval. Both cars and driving styles vary. The OLS allegedly calculates all factors pertaining to the engine and the driver and thereby makes its oil change recommendations.

The typical recommended interval for gasoline-fueled passenger cars and light-duty trucks is 3,000 miles (4,800 km) or three months, whichever first occurs, when outside temperatures are below freezing and trips are short. These conditions are considered severe duty. For ideal driving conditions, relating to long trips with mild outside temperatures, the interval can be expanded to 7,500 miles (12,000 km). Starting with the 2000 model year on certain vehicles, GM will raise the maximum mileage allowed for Oil-Life System-equipped vehicles to between 10,000 and 15,000 miles (16,000 and 25,000 km), depending on vehicle brand and engine.

**muffinman** · 08-13-2007, 02:34 PM

Thanks Darcy!

**Skarch** · 08-13-2007, 05:57 PM

Just as a rule of thumb, I switch mine in all my cars every 5000 miles. It makes it easy to remember (even for my wife

) however, my cars see pretty light duty, and don't pull trailers or anything of that caliber. Make sure you use a top tier oil and filter (fram is horrible, BTW) and you should be good for that mileage. Hope this helps.

**muffinman** · 08-13-2007, 06:46 PM

Thanks Josh, This is a totaly new vehicle to me and am very interested on how this thing thinks. What an awsome truck!!

**Diceman** · 08-14-2007, 04:35 PM

i normally go once per year on an oil change. but that is on two cars that see like <5000 miles a year if that. ;)

in previous beaters i have gone 8k-10k miles between oil changes and put the sloppiest cheapest oil and filters i could find. they ran sweet. with this truck i'll probly stick closer to 5-7k and i will be running 15w50 fully synthetic.