I will need to replace the oil pressure gauge on my tractor and was wondering what the upper range of oil pressure would be. Gauges with colors only kinda scare me! Sources for replacement gauges would be appreciated too. Thanks! Elton

In all the Cat manuals for the D 315 engines the reference that I have found is that the oil pressure relief valve is set to bypass at 90 psi, which would be the high end of the range.

The only reference that is consistent through the books is "operating range" on the gauge.

Here is the page from form 30522, Servicemen's Reference Book, Caterpillar Diesel Engines, (4 1/2" bore 4- cylinder). The reference states "By controlling the inlet, the oil pressure at the bearings is limited to approximately 30 psi at the rated engine speed, ..."

My D47U operates from 45 to 50 psi on the gauge when hot at rated RPM. I use 15 W 40 Oil (Same as in my Green stuff) I added a gauge when I had problems with diesel getting into the crankcase.

Other than that I don't know clearances ETC so nothing more than that. I believe PD is correct about the 90 PSI bypass setting.

15 W 40 is pretty stiff at zero and below so it could easily get to 90 PSI when cold. Mine pegs the needle when started at 10 degrees and below even using block water heater.

Hi Team,
scan below may help or not.
Cheers,
Eddie B.

Thank you to all of you. I am a parts guy at a diesel distributorship (not CAT) and tend toward precision where possible. It looks like for the oil pressure and likely temperature also, I should seek the closest thing to a replacement or a 100 psi gauge for the oil. Usually you want the operating range somewhere in the center of the gauge where it is the most accurate. But with a relief of aprx 90psi and a minimum at 4psi, the 100 psi gauge is probably the best. Other comments are welcome.
Elton

I don’t know how a relief pressure of 90 psi figures into the actual oil pressure since the pressure control throttles the suction of the pump to regulate pressure to the approximately 30 psi as mentioned. This throttling valve has a sensing line on one of the centrally located main bearing caps, so it is regulating effective crankshaft bearing lube pressure. Maybe it takes quite a bit higher oil manifold pressure to deliver the 30 psi at the bearings.