Low oil pressure on high mileage motor (1 Viewer)

Joined
May 1, 2017
Messages
21
Location
Portland, Oregon
I am looking for advice on a possible oil pressure issue.

We have 96 LC with almost 330k miles on the original motor. The vehicle drives great but we noticed recently the oil pressure seems lower then it has read in the past. The dip stick indicates the oil level is good. See pictures. I have included a picture of the manual for reference. The first picture of the oil pressure gauge is at idle.

We are planning to put on a mechanical gauge to verify the oil pressure. If low, it could be the oil pump but I have heard that isn’t a easy job to replace. Of course, it could be another issue. We recognize that the engine is high mileage and is likely showing it’s age.

As a side note, we are using a Castrol synthetic high mileage oil.

DCCD24EA-6849-4D4A-9701-5A01D967A8CD.jpeg
70173D8B-7311-40CA-9918-9BE1490EB7D1.jpeg
29496BBF-BF54-45DD-8D19-7442A7286912.jpeg
 

Howard705

TLCA 5505
SILVER Star
Joined
Feb 1, 2013
Messages
1,443
Location
Central Illinois
Lots of threads on this- gauge is iffy. My observation is that most gauges (any kind) are only calibrated to their level of accuracy. Note there are no numbers on these. Most bled off through worn bearings. run heavier oil. Don't worry about it.
 

baldilocks

Battle Ground, WA
GOLD Star
Joined
Jan 29, 2014
Messages
6,625
Location
Battle Ground
The sending unit could be going bad. The wire connection at the sender could be loose or corroded. Do not run a Napa/Wix brand oil filter as these have been defective and ruined more than a couple engines here on Mud. There is nothing wrong with running oil with a higher viscosity as mentioned above. My engine has 305k miles and runs like a champ. I’ve been running Delo 400 15/40 since I bought it at 265k. I suspect that you will discover ample oil pressure on the mechanical test gauge when you do that. The rule is, 10psi for every 1,000rpm. That means 7psi at idle is enough and 50psi at 5,000rpm.
 

flintknapper

SILVER Star
Joined
May 22, 2004
Messages
9,132
Location
Deep East Texas
Ignore it. Run a slightly higher viscosity oil if you like....but I can tell you as long as your engine isn't knocking you are fine.

I put a digital oil pressure gauge on mine (in conjunction with the factory unit) just to monitor it and regardless what your dash gauge reads (they are known to read low) you probably have 8-12 psi at idle. My engine has similar mileage and that is what I see.

Just be CERTAIN to always run a good quality oil filter (NO WIX) and check your oil 'level' often. Then put the oil 'pressure' out of your mind altogether.
 

baldilocks

Battle Ground, WA
GOLD Star
Joined
Jan 29, 2014
Messages
6,625
Location
Battle Ground
Thanks for the advice! Makes sense. We’ll verify the psi via the mechanical gauge and try a slightly higher viscosity oil.
If the oil pressure is indeed low as indicated by a properly calibrated mechanical gauge, you might look into verifying the crank pulley bolt torque. Have you experienced any perceived weakness in the power steering?

Be aware that 20w50 is specified on other continents where our EPA hasn’t choked the people with its tentacles. I live just a bit NE of you and there has been no problem running 15w40 year around in my cruiser and my Cummins pick-up so 20w50 would probably work too. We don’t get extremely cold weather.
 
Joined
May 1, 2017
Messages
21
Location
Portland, Oregon
If the oil pressure is indeed low as indicated by a properly calibrated mechanical gauge, you might look into verifying the crank pulley bolt torque. Have you experienced any perceived weakness in the power steering?

Be aware that 20w50 is specified on other continents where our EPA hasn’t choked the people with its tentacles. I live just a bit NE of you and there has been no problem running 15w40 year around in my cruiser and my Cummins pick-up so 20w50 would probably work too. We don’t get extremely cold weather.

Didn’t think of that. Good point. I haven’t noticed any weakness in the power steering but will pay more attention to it.

We’ve been using 10w30 and agree that a heavier weight oil is worth trying. Thanks!!
 
Joined
Sep 27, 2020
Messages
18
Location
Oklahoma City
I noticed a similar issue on mine today. 266k miles on the original engine. Oil pressure gauge sits where yours is at and at idle after the engine has warmed up the car rumbles pretty significantly. It doesn't do this at higher RPM. Following this.
 
Joined
Sep 5, 2020
Messages
32
Location
US Military (Stationed in Middle East)
Lots of threads on this- gauge is iffy. My observation is that most gauges (any kind) are only calibrated to their level of accuracy. Note there are no numbers on these. Most bled off through worn bearings. run heavier oil. Don't worry about it.
After oil changes, new filter, new sender unit, verifying wiring and gauge operation, listening to the engine, observing splashing inside the oil cap/spout, clearly seeing no leaks, and spending hours on IH8Mud with endless 'low oil pressure forums', I to will "Not worry about it". I'm done losing sleep over a fine working engine.
 

Users who are viewing this thread

Top Bottom