'94 D90 oil pressure light on and LOUD valvetrain noise
Wondering about a mate's '94 D90 that seems to be having some heart issues...
Firing it up cold results in the oil pressure lamp remaining lit and very loud valvetrain racket. I was going to plumb in a mechanical gauge and take some readings but have a few questions before I delve in;
1. What size fitting do I need for the gauge? I assume I remove the oil pressure sending unit and thread the gauge into the opening?
2. What does LR consider healthy cold and hot oil pressure for the 3.9 V8?
3. If the pressure is indeed low, do the D90s have oil pump issues like Discoveries do or would it more likely be something like a clogged pickup tube? Anyone experienced sludged up oil returns?
4. If we elect to do a top end overhaul, what would be recommended to replace? I am assuming lifters, rods, rocker arms and rocker shafts?
Thanks all for any help!!