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Oil pressure


fuzzypuppy
05-01-2015, 02:44 PM
I have had this problem for some time but hoping I can finally fix it.
I have a 91 2500, 5.7. 247.000 mi
Since owning the truck the oil pressure has been acceptable at 10 psi per 1k of rpm, "formula."
The problem is the pressure being too static, 2500 to 3000 rpm gives me close to 40 psi. At idle it sits at 25/30 psi, that's it, A 10 to 20 psi range seems odd to me.
I have tried several gauges with the same readings.

Considering an oil pump change to a high volume pump, melling has the m55hv I'd like to install, hoping to bring up pressure with more volume, (I know) "my thinking is" more volume will overcome loss due to bearing wear since the engine has a lot of miles. I bought it with 100k and the oil pressure has remained pretty much the same through the 140k I have run it.
I would appreciate any idea's or similar experiences/fix's.
Thanks.

MagicRat
05-06-2015, 08:42 PM
Your oil pressure readings are fine. Completely normal for an engine with some miles. I do not think you need to change the pump at all. Yes, a new pump may get you a bit more pressure, but that will not help your engine. The pressure you have right now is more than adequate.

If you are using it for heavy duty use, like towing, consider a thicker oil in the summer. If you are using 5W-30, consider using 10W-30.
If you already use 10W-30, consider 10W-40 in the summer.

fuzzypuppy
05-21-2015, 07:04 PM
Thanks for the reply Magicrat.
I do run a 10/40 wt,
I will be looking to tow an RV soon but won't do that until at least a refresh for reliability.
Right now just stop n go, on fairly steep grades in the So,west heat fishing/camping.
I was considering the new pump because I have to pull the pan on my next oil change after a lube place I used while out of town trashed my drain plug and pan.
I was concerned with the pressure after my last trip when pulling a big grade the truck got hot (not boiling over) and the oil pressure dropped farther than I liked.

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