09-07-2015, 09:37 AM
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.
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.
1990 Peugeot 205 GTi 1.9 // 1991 Peugeot 205 GTi 1.9 16v // 1992 Peugeot 205 GTi 1.9 // 1999 Peugeot 306 HDi Estate