1991 M923A2, Cummins 8.3 higher than usual oil pressure, and oil leak question

[Western PA M923A2]

Hey fellow SS'ers! Been a while since I've been on here. Last time it was a coolant issue... rising temps and loss of heat. Got that all straightened out. Ultimately, the brass elbow that comes from the shutterstat that sends air pressure to the fan clutch actuator was COMPLETELY PLUGGED UP. I replaced it and VOILA!... no more over temp issues, and imagine this - the fan actually kicked on several times where it never did before! My guess is that all of that backed up air pressure that wasn't getting to the fan clutch was bleeding back through the shutterstat and ultimately into the coolant and causing all of my issues.

Anyway... as to the new one - I have a small oil leak that I thought was from the oil pan since some of the bolts were kinda loose. Well I snugged them all up and there was still a small trickle that I think is really coming from the front of the crankshaft. Also, suddenly my oil pressure gauge is showing higher than usual pressure. It's always been at around 30-45 psi after she's warmed up and while driving, but now it's up around 60-65. Could a clogged up oil filter cause this? I'm guessing a restricted flow is causing the higher pressure.... so any thoughts and wisdom would be most welcome!

 

[simp5782]

Easiest solution is to borrow a pressure tester and see what you have at the port. Never trust the gauges really. Could be a bad spring in the bottom of the filter especially if it hasn't been replaced in a while.

 

[Western PA M923A2]

Well I've put around 2300 miles on her since I bought her last summer and I haven't changed the oil or filter yet. The guy I bought it from owns a truck repair shop and said he had changed the oil shortly before I bought it, but how long before, I really don't know.

 

[simp5782]

That's on you. my first rule on any vehicle I buy unless it is brand new is to change the oil atleast and then go down the list of other fluids if I believe they need it. That way I know my maintenance schedule and not theirs.

 

[Western PA M923A2]

WHere should I connect a pressure tester... where the oil pressure sending unit is?

 

[simp5782]

WHere should I connect a pressure tester... where the oil pressure sending unit is?

Yep.

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[WillWagner]

Oil filter will not cause higher that "normal" oil pressure. As Simp said, verify the gauge first. Next will be the pressure regulator in the oil cooler housing, it is probably scored and sticking, could be from the high coolant temp issue, the housing is aluminum and the plunger is steel. Just take it out and polish it with crocus cloth.

 

[WillWagner]

The plunger, not the housing!

 

[Western PA M923A2]

Thanks both of you, Simp and Will.
As for the leak, if I need to change the front crankshaft seal, looks like the radiator will have to come out to gain access to pull the front pulley... correct?

 

[Buffalobwana]

Despite the problem, since he's messing with the oil pressure sending port anyway, would now be a good time to switch to a mechanical oil pressure gauge? I bought a Bosch for mine since it pooed out on me. $20 and a more accurate reading.

Kill two birds with one stone. Get a new gauge and step one in troubleshooting.

 

[simp5782]

Yes mechanical is better.

And yes you will feel better pulling the radiator it takes whole 20mins to have it out.

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[Western PA M923A2]

UPDATE - - - Problem solved! Got under there today and after wiping down a nasty oily mess I was able to trace the leak down. It was coming from the very bottom of the front timing cover. A few of the 10mm bolts had loosened up, and of course the two that I needed to snug up are the hardest to reach, but I was able to get a 10mm open ended wrench on there, so adios to my nagging messy oil leak!

 

[Buffalobwana]

That's great! I had the exact same problem, (I think I fixed it!) and your mind races through all the possible seal problems. And $$$$ and time spent adding up in my head. It's very nice feeling to fix it with a turn of a bolt!

 

[Western PA M923A2]

I hear ya!! My mind was going to worst case scenarios and I was thinking it was the front crankshaft seal. I got it licked, FOR NOW. I only had a short 10mm wrench and it kept slipping off the bolt. I need a longer and thinner one to really get in there and make sure it's good and snugged up, so a $5 wrench is well worth the investment to fix it right.