My truck showed 38 psi at at 2500 rpms during a recent trip. It idles at 20 psi. These numbers are from an autogage electric gage I installed so they may be off a little but 38 seems low. It would jump to 40+ when the engine revved over 3000. I'm running 5W-40 T6. Should I think about doing the oil pump soon?

 

I believe the pressure relief valve for d2 is 50psi, which would make me think something is wrong if you are only getting 38 psi.

 

It is 50 psi which is what made me wonder also. The engine sounds fine but I would expect it would hit 50 psi at that rpm.

 

The shortblock had been replaced in my truck shortly before I bought it, but it is likely that they didn't replace the oil pump while they were at it. So that means that my pistons, cam and crank have 40,000 miles on them while my oil pump has 110,000 miles. The engine is smooth and runs great, but with the pressure running at 38 to 40 psi on the highway I think the pump is starting to get weak. Looks like I'll be digging into the front of the motor before too long for that, and I'll get the water pump too while I'm there. Plus I need wires so I might as well do the valve cover gaskets while I'm replacing those, and since I'm almost there I'll get the valley gasket too. That will only leave the rear main to drip oil on my driveway.

 

Don't look for trouble.
That oil pressure seems fine.
You can put in non-synthetic to raise the pressure.
You can also change the main bearings down below to increase the pressure.

You can also pull the pan and remove the sludge and clean the pickup tube screen.
That may help a bit.

To me - messing with the oil pump is a risk.
Not broken don't fix.

 

Knowing the history of the truck since the shortblock was replaced, I doubt there is much in the way of sludge in it. It had 17,000 miles on it when I bought it and I have been running Rotella T6 in it for the past 23,000 miles and it has been changed every 4,000 miles. I realize the oil pressure is good enough, I just would expect to see it higher given that the engine is relatively new. Just thinking long term. A worn oil pump lubricating newer bearings is not an ideal situation in my mind.

 

There you go.
T6 is like running water in it.
Very thin Synthetic.
That's OK.

But you will get better oil pressure with Casteroil 20W/50 - old fashioned oil.
Of course in the winter running T6 is a good thing to do.

And since you are on T6, you gotta stick with it.

 

One, or both, of two things can cause oil pressure to decline over time: Oil pump wear or damage, of course, and main bearing wear.

As jfall says, you are running way too thin of oil in this engine that has camshaft/ flat tappets in an older design configuration, unlike more modern overhead roller valve train designs. You should definitely be running Rotella T6 but 15/40. These Rover engines MUST HAVE an oil with zinc additive chemical, that was in ALL oils at the time these engines were common, but now that zinc additive has been almost eliminated from most oils, (only remaining in oils, such as Rotella, T6, designed for diesel engines, which still use flat faced camshaft/tappets as does the Rover v8. Change to 15/40; check pressure again. If still low, your oil pump and/or mains are worn; should be tended to. The zinc additive give.s badly needed cushion at wear points on valve train, which isn't offered by oils without the zinc additive, though synthetic oils may offer it to some degree, but safer to stick with zinc additive in good quantities in oils having it. If you run oils not containing this additive, you are risking prematurely wearing out valve train components, camshaft, lifters (British call them tappets), push rods, rockers, shafts