I am having a very strange problem with my car right now that I've never run in to before on one of these. My car is a 1998 S70 GLT. When it's very cold outside (25 or so) the oil pressure light stays on longer than normal, then goes out. If I rev the engine, it comes back on until engine speed drops. If I drive off, the light will come back on above 1500 RPM, then it goes back out if I let off. After the engine warms up, it's completely fine. The conditions I've described under which the light is coming on are conditions where oil pressure should be at its HIGHEST- cold engine, higher RPMs, etc. I haven't yet put a mechanical O/P gauge on it, because it's too darn cold right now, but I'm wondering if the warning lamp on these cars is designed to come on with high oil pressure, or if there's a problem with the sending unit (yes, I know that's rare.) The car exhibits none of the common signs of low oil pressure. I am planning on changing the o- rings soon, as the oil pan gasket leaks, but other than that, I don't see anything wrong.

 

Maybe oil to thick?

 

I don't think so... I've been using Amsoil 10W30 all along. I'm curious, though, if these vehicles will alert for high oil pressure as well.

 

I don't think they do. But maybe the o-rings are bad and when the oil is thicker it is pushing it out the o-rings under the pressure.

 

Ah, okay. That's a possibility. Perhaps I'll sideline this car until I can do the oil pan/ O-rings.

 

thickness of oil not your problem

At 25F a 10W will have the same viscosity of a 5W more than likely. Now at 0F it's a different story. Amsoil won't have any cranking or flow problems at that temp or any other basically. That's a really good oil.

If doing the oil pan o rings is going to take a while, then change out the filter (you will only lose 1/2 quart of oil) with a Mann or any other high flow oil filter. See if that helps.

It's probably the o rings though