99 chevy tahoe LT 4x4 low oil pressure reading only after its warmed up sitting at an idle and the same when I am in drive on the brake. Check gauges light comes on when it drops down to approximately 5-8 on the tack. As soon as I get on the gas the light goes off and the tack reads up to 13-16. No engine noise as of yet and only had to add one quart in 2 months. No leaks found. Has me wondering if the filtering screen for the oil pump might be clogged? I dont want to tear into it for nothing if thats not the problem. Any suggestions what could be causing this?
This is typical of worn connecting rod and crankshaft bearings in high-mileage engines, but it can also be caused by a defective sending unit. The best place to start is by installing a temporary mechanical oil pressure gauge to see exactly what is happening. If the pressure really is low, switching to one grade higher viscosity oil might help.