Ok I'm new here so I'll try this again. Went through the whole speal and it wouldn't submit my post. Don't know if my server is dropping out or what? I didn't see any keep me signed in box but here goes.
Recently bought a 98 Ram 1500 QC Sport 4WD with a 5.9 in California.( Pre-pandemic). Nice clean loaded truck with 104,00 miles and a leaky plenum lol. I drove it 1800 miles home and went to work on the plenum and figured I'd Check and replace the water pump, timing chain and pull the oil pan for a look. The oil pressure only runs like 29 psi at 2500 rpm which isn't uncommon but could be better and we all know these oil pumps have issues so why not replace it anyway? Pulled the pan and no sludge or anything to plug the pick up so that was good but I noticed a shiny spot (silver dollar size) with no paint in the back of the pan behind the oil pump. That seemed weird because the spot looked like the paint has been worn off like that area is being sprayed with a constant stream of pressurized oil. My back was hurting me but I crawled under the truck to see if the oil pump pressure relief port faced that way but I didn't get to good of a look cause I was hurtin alot. I'll get to the bottom of it when I'm feeling better but in the mean time all I can do is speculate. Any one seen this before?

 

Replace the pump with a high volume unit. The pressure relief valve is part of the pump.

 

I am aware of that . I couldn't remember if the valve vented back to the pan or internally to the low pressure side but now that I think about it I believe it is the latter.
Like I said earlier the paint looks like it's been worn away rather than flaking off so the only other scenerio I can think of is that there is a defect on the high pressure side of the pump that is letting a stream of pressurized oil escape and bathe that spot. I'll pull the pump for a better look . It's Ok I only look crazy. lol

 

Crazy is good. You'll fit right in here.

 

My back is finally feeling a little better so I pulled ,cleaned and disassembled the oil pump for inspection. The first thing I noticed was no gasket between the pump and motor. I checked everything out and the only thing I found was the machined mounting surface of the pump when checked with a precision straight edge from bolt hole to bolt hole showed the surface was not flat. One side tapered away from center about ten thousands. Ok, so question is does .010 gap from center plus no gasket equal enough gap for a high pressure oil leak? Would proper torque seal .010 gap? Maybe maybe not. I guess ill never know for sure but my new pump checks perfectly flat and I'll either use a gasket or an anaerobic sealer this time. If my oil pressure goes up dramatically with the new pump I'll consider that a possibility but without testing the old pump in a controlled environment it's all just speculation.

 

Use the gasket. I think the RTV isn't a good idea.

 

I know exactly where you're coming from about the sealer but its not an RTV . This is a Hydraulic (anaerobic-cures in the absence of air) sealer that contains no solids and is basically the consistency of blue loctite. It's totally safe for oil system components and any excess will stay liquid and simply dissolve in oil. There's really no down side to it other than it will only fill up to .015 gaps, that and it's very expensive. It only requires a tiny amount. 2 or 3 drops would be enough for a fuel pump flange. The paper gasket that came with the pump is so flimsy if I use paper I'll make my own from thicker material. On a different note I got a high volume pump and from what I gather they put out 20% more volume than stock across the board. So if that's the case theoretically at any given rpm there will be up to 20 % less oil available than what the stock pump would have available at the same rpm. The $64,000 dollar question is.......... will the pump out put ever be enough to starve pump supply if the proper oil level is maintained? If so why not overfill 1/2 a quart?

 

You don't want to overfill. Then you run into interesting problems like the oil level actually being higher than the lowest point of the crankshaft..... and the crank literally whips your oil into a froth. The pump will still move it around, but, pressure drops off substantially, and aerated oil doesn't lubricate that well.

I put a high volume pump on my 5.9, and never had an oil starvation problem. Even when it was a quart or two low. (that truck went thru oil like no ones business...... even after the plenum fix.)

 

That's good know it's not all gloom and doom some say that it is . I not sure what forum(s) I've seen this on but a few guys were claiming high volume pumps should be avoided because of oil starvation damaging their engines. Although skeptical I've been thinking for a while now just in case before I put the pan back on maybe I should do a little experiment and measure just how the much oil you can safely put in the pan before involving the crank. Just for giggles I'm going to take a few minutes and do it. It will be interesting to find out.