I have a 99 disco II with 104K miles on it and the red oil light just came on after hard acceleration on a highway.....The oil dipstick shows it is full and clean. I have been hearing some valve noice on one side, now I hear it all the way across the engine (valve noise) sounds like the top is dry. SO the question is what do I look at, Oil pump, clogged strainer? When does the oil pressure drop to turn the light on, I think I know it is below 8psi but again does that point to the pump or the strainer or both?????

 

I would start by dropping the oil pan and cleaning it along with all the pickup tubes and such. But I haven't tackled this problem on my 97 yet so...

 

Put a gauge on it. Do not drive it anymore until you have it tested.

Drop the pan first and check the strainer. If it looks good, pull the front cover and check the gears in the pump. You have to drop the pan to get the pump off anyway.

If you need directions, the Rave manual is in my sig. free download.

 

I have it at the shop to pull the pan and check.

So do the oil pumps fail catastrophically (quickly and violently) or do they slowy stop working......Because - I have been having valve noise vrom the drivers side that has been getting progressively worse, and I've been trying different things (oil changes, marvel mystery oil, etc) to quiet what I thought was a noisy lifter..

 

they go out both ways. You would never know. That switch trips at 8 PSI and normal pressure is in the mid to high 30's.

Adding a gauge is the best thing to do with these trucks.

 

As already mentioned, quit driving it TODAY, get an oil pressure gauge and when stone cold test the pressure at an idle and 2000 RPM's, then again when warmed up at idle and 2000 RPM's.
Get back to us with the 4 sets of numbers then you can decide what to do.

 

It's at the shop (dropped it off yesterday to sit overnight) and they should have the readings for me today

 

If you have no oil pressure at idle I'd turn it off and not check at 2,000rpm.