What weight oil does a 1999 Saturn SL 22 take?

Answer 1

The oil viscosity is more dependent on the condition of the engine than on the year or model.

A new engine, in perfect condition with absolutely NO wear on the rod/main bearings calls for 5W15 oil.

As the engine wears a little and the space between the bearing and the crankshaft opens up, you should use an oil that maintains the oil pressure.

At first, switch to a 10W30, and if that doesn't keep the oil pressure up, change to a 15W40.

But once an engine has been down the road a good distance, it's time to change to a higher viscosity.

Note too, an engine that has been properly maintained and has not been abused will also not wear as fast. I've seen a Saturn with 160K miles that still used 5W15 oil, and I've seen vehicles with 50K miles that have had to use 15W40. There are too many variables to make a blanket statement about what oil viscosity you should use in your engine.

Simple rule: If the oil pressure drops significantly when the engine is hot and at an idle, change to a higher viscosity. A little drop is okay though, just so long as it doesn't drop more than half way down the gauge.