oil gage works and then stops working after about ten minutes.

[yellowstonebill]

I buy 5 tons for farming and ranching here in North Dakota and now and then I get a truck that the oil gage works right after the truck is started but after a few minutes or when I look at it again it is down to zero. I always shut the truck down and check for leaks and check the oil. The last time this happened was yesterday and it was cold. The oil was just above the low mark so I added half a gallon and restarted the truck. The gage went to 100 lbs and stayed there for 5 minutes and then quit working again. I let the truck run for over an hour listening to the engine and could not anything alarming to say that it wasn't getting oil and looking in the filler cap I could see that the cam was getting lubricated. Is this common? I just put new batteries in. Just 2 of them in series. I have the small wires hooked up at 24 volt. Is that correct? I think that they are for the gages.

 

[73m819]

Sounds like a bad oil pressure sender, hook up a mechanical oil pressure gauge to see what the REAL pressure is, I have the same issue with a temp. gauge.
Also it depends on what 5t as to the small wire, on the 809 series it goes to the cold start manifold heater spark plug, on the 939 series, it goes to the low side of the heater

 

[dmetalmiki]

Yep, simples..convert ALL your trucks to mechinical oil pressure gauges..and then, what you see is what you have!.

 

[74M35A2]

Some reassurance, my gauge behaved exactly the same. Would read mid scale on cold start, and then on the zero pin once warm. This was as received, and also after replacing the sending unit, and gauge. It concerned me so much when I was looking for a truck to buy that I asked each of the sellers to please have a mechanical gauge installed as part of the viewing. All the engines then showed great oil pressure cold and hot. Actually, without searching, I have not openly heard of a Cummins having low or zero oil pressure yet.

I did change out my electric gauge for a mechanical one. Day and night difference. I have 80psi on a cold start, 60psi hot freeway driving, and 30psi at hot idle. This is all with Shell Rotella T 15W-40 in a 6CTA8.3.

 

[Tornadogt]

I agree with going with a Mechanical oil pressure gauge but also double check the small wires to the battery, One should be 12V not 24v, I believe it is for the low speed on the blower motor and have be told it does something else also..

 

[Coffey1]

Here's how you check sending unit.
Get ohm meter and put pos on sender terminal and negative to ground.
Start truck and have some run throttle up and down ohms will change as throttle goes up and down.
If this checks out change gauge
All dash gauges are 24 volt.