oil pressure

[HDIkyle]

What is the expected oil pressure for an xud? Fitted an oil cooler and Mines gone up I have a 100psi gauge and now isles warm at 50 and off the gauge when driving. Where without cooler was 20psi idle and 70/80 driving

[powerandtorque]

XUD9 engines should have a 5 bar pressure relief spring, so you shouldn't really be seeing more than that with hot oil. 5 bar is approximately 72psi, so that tallies up with the 70-80 figure that you were seeing before.

If it's gone up that dramatically since fitting the oil cooler and the reading is accurate, then I'd hazard a guess that the oil cooler must have a massive restriction somewhere.

Obviously lower oil temperature will mean thicker oil and more pressure, but I'd be surprised if you've had such a dramatic change in temperature that the pressure figures have changed that much. Big clue will be if the figures are also dramatically higher a few miles into a journey when the oil won't be fully upto temperature.

[Piggy]

that is odd. As said there is a 5bar limiter basically.

Mine is 5 bar cold at idle.

Once warm about 2bar, climbs with rpm to no higher than about 4.5bar flat out

[HDIkyle]

It stays same once warm even after 25 30 mins when I get to work Thats with oil temp at 80-85.,its only a small 9 row cooler

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Where is the relief spring?

[powerandtorque]

Relief spring is part of the oil pump, sandwiched between the main body of the oil pump and the pickup casting.

[HDIkyle]

Argh so not something easily checked then, Will try get another cooler to try its a second hand cooler so might as simply as a blockage in there