Oil Pressure M998

[Economist]

The TM indicates that operating oil pressure should be in the 40 to 60 PSI range. My M998 is relatively new to me, but I noticed that it is consistently just above 30 at idle. I did an oil and filter change and triple check fluid level. Still runs at just above 30 at idle. Is this normal? Just doesn't seem right.

 

[emmado22]

Your gauge could be off.

 

[SETOYOTA]

or your engine is bad

 

[firefirefire90]

you say it's at 30 when idle. Does it change when you drive?

 

[usmc81301]

ine runs a little above 30psi when cold. At operating temp it runs down around 5-10 psi and as far as I read that is the range it should be in when warmed up.

 

[BIG_RED]

My M1009 is the same as usmc81301 describes. Close to 40 PSI when idling cold. 5-10 idling after warming up. While driving, varies with RPM from about 10 - 40 PSI.

 

[Economist]

or your engine is bad

Alright, Mr. Black Cloud. Let's hope you are not right on this one.

 

[Economist]

you say it's at 30 when idle. Does it change when you drive?

It goes up when I drive. Usually in the 40 to 60 range.

 

[Economist]

My M1009 is the same as usmc81301 describes. Close to 40 PSI when idling cold. 5-10 idling after warming up. While driving, varies with RPM from about 10 - 40 PSI.

I don't think I have ever seen PSI that low on my M998. Doesn't that concern you given the TM range of 40 to 60?

 

[nattieleather]

If your in the TM range of 40-60 when driving then your motor is fine. Enjoy your ride!

 

[SETOYOTA]

Hello its me, mr black cloud. I don't think you have anything to worry about. Other than oil pressure indicator does everthing else seem fine.?

Are you getting any blow by out of the oil filler?

How about posting a pic. of your rig.

 

[Economist]

Hello its me, mr black cloud. I don't think you have anything to worry about. Other than oil pressure indicator does everthing else seem fine.?

Are you getting any blow by out of the oil filler?

How about posting a pic. of your rig.

Dear Mr. Black Cloud,

No blow by out of the oil filler.
I am just getting my arms around this rig. I have had it about 6 weeks. Changing all the fluids and getting to know her. She idles a little rough, but it is my first 6.2L. Good acceleration (for what she has in her). Have had some occasional slow starting issues, but Ted has me installing the 4 pronged grounding strap to potentially resolve that.

Photos attached... First 4 are from the previous owner. 5th is delivery day. Have already replaced all the radiator hoses, flushed the coolant, engine oil and filter change, trans oil and filter change, replaced dried out trans rubber lines, tightened a loose half-shaft retaining bolt, added a front brush guard, added a air lift bumper and a Rhino tire carrier, and a few other small things.

Thanks for all the feedback.

 

[Economist]

42 M10 ammo trailer
42 GMC CCKW 352
42 M2A1 Auto-Car Halftrack
42 M3 37mm anti-tank gun BATF registered live
43 Dodge WC51
60 M274 Mechanicle Mule
7? M105A2
87 M998 HMMWV
92 M101A2
95 M116A3
05 M1101

Mr. Black Cloud, how do you decide which rig to work on?????

 

[SETOYOTA]

Its easy .....there all broke at some point. You have a very nice truck there. My HMMWV is my favorite MV. I would not worry about the oil pressure.

 

[Economist]

Its easy .....there all broke at some point. You have a very nice truck there. My HMMWV is my favorite MV. I would not worry about the oil pressure.

Careful, I may have to change your nickname to Mr. Sunshine.

Thanks for all the quick responses. I plan to enjoy this one for a long time to come.

Best Regards,
-Economist.

 

[Augi]

My stock oil pressure gauge has always been on the fritz. At highway speeds it usually reads 25 or 30psi but sometimes zero to five and sometimes places in between.

I went over to the auto parts store and bought a 3/4 sweep mechanical oil pressure gauge for cheap money (<$20). I put a T fitting in front of the stock oil pressure sender and plumbed it through the speedo cable hole into the cabin. It's mounted on on of the screws that holds the turn signal lever to the column (no cutting up the vehicle and it'll come right out like it was never there). Now I don't have to worry about the oil pressure anymore because I know it is good based on the mechanical gauge!

Augi

 

[nattieleather]

Nice looking rig you got there! As you looked at Mr. Clouds aka Sunshines list of vehicles you can clearly see why it's called OD Fever and OD Disease! If the M35A3 in your avitar is yours then it looks like you have a bad case of this curse! At one point in my life I owned Two M151s, 2 duces (M211 and M35A2) a CUCV M1009 and three trailers (M416, M105, and MKT) I realised that I don't have enough time in my life to keep all vehilces working good and looking good. So over time I've wittled down to one vehicle and now I just have one project truck in the garage that can't say will be my last MV but is possible it will!

Anyway sorry to go off the track, Nice HMMWV enjoy your ride!

 

[Economist]

No questions this is a disease. I bought my H1 and then kept looking for the M998. Hard to justify both. Settled on keeping those 2 and letting the M35A3 go. Hard choice, but I am with you and the difficulty of keeping all of the in tip top shape.

Why do we keep looking at the auctions when we are out of space to store these things??????

 

[nattieleather]

If we had the answer to that question we would all be wealthy and retired enjoying our hobby... :Lol:

 

[xmiltm998]

Thats normal mine is the same, its higher when the engine is cold because the oil is thicker.