: 05 STS V8 4 motor oil percentage question!

07-25-13, 04:32 PM
Hi everyone, as you are aware, I have only had my car for a month but was curious about the motor oil. Is the motor oil percentage based on miles driven, hours engine is running or oil viscosity? Thank you!

07-25-13, 04:48 PM
Rpms speed duration heat etc

All of this is based on synthetic oil though. Do not run anything else if you plan on using it.

07-25-13, 05:41 PM
Excellent! I plan on running synthetic. Thank you!

07-25-13, 06:01 PM
Run the OLM to 0%. At that point you have two gas tank fillups to get the oil changed.

07-25-13, 10:55 PM
As noted in the Owners Manual, use oil of GM Standard GM4718M or better. I use Mobil1 as it says on the filler cap.

My OLM reaches 0 around 12,000 miles, a bit over a year, so I'm technically overdue. On the other hand, the original owner of the car did me a great favor by 'breaking in' the engine with the following schedule of dealer-performed oil changes: 3900, 7203, 9198, 13241 & 26164 miles. I rarely need to add any oil between changes.

My wife's Hertz car certainly didn't get this treatment, having bought it with less than 12,000 miles on the odometer. I wouldn't be surprised if it still had the delivery fill! It uses a little oil, but less than a quart in 10,000 miles. She sometimes goes 18 months between changes, insisting that following the OLM should be enough. She does take at least one long drive (more than 3 hours) every month so maybe condensation buildup isn't an issue.

Yeah, I know. I've told her. You want to read the manual to her? Be my guest.

It's her car.

One secret to a happy life: Have a happy wife.

07-26-13, 08:31 AM
Or, you can always go way up ^^^ to the Cadillac Technical Archive in the top black bar and read the article on how, when, and why the GM OLM works. The article was written by a Cadillac Northstar Powertrain engineer with input from the OLM program writer.

I follow the OLM in my 2002 FWD STS or once a year (owner's manual), because for the last 6 years my driving distance is way down - less than 7,500 miles a year. FWIW I run Pennzoil Platinum 5W-30, a WIX oil filter, and the engine uses less than a quart of oil in 6,500 miles. At that annual oil/filter change the OLM is at about 35% - 50%, depending on how much city driving I get into: City driving is murder on an engine; highway is easy on an engine, and I'm in a mostly rural environment (I DO run the dog snot out of the car on occasion, including runs to 135+).

07-26-13, 09:07 AM
Run the OLM to 0%. At that point you have two gas tank fillups to get the oil changed.The OLM has a 100% safety margin. In other words, if the car was driven under identical conditions, you could reset the monitor, and run it to 0% again, as long as it didn't exceed 12 months or 12,000 miles.