What is "normal" oil pressure at idle?

I'm asking because I swore it was 40 (according to the stock gauge) but today I saw it dropping down to the hash mark left of center when I stopped at lights... did I remember wrong and this is normal? If it's not OK, what is it indicating?

 

I know on the '06s the factory gauge is only an idiot light-it's essentially showing what the ECU thinks oil pressure SHOULD be, not actually what it is. It's to (in the words of the FSM) be more in line with "customer expectations."

The only way to test is to put a real gauge on the 1/8"NPT port directly above your oil filter. Start the motor, and see what warm pressure is at idle and at speed. At least that way you have an idea as to what you're really staring at.

HTH-

 

I've got 5w-40 in mine now,and its right at 40 when warm. When its cold,I'd guess its at about 65-70.

 

If thats off the OEM gauge you dont really know... its not a gauge... its a algorithm... if the computer sees oil psi from the psi switch it operates the gauge based on a bunch of parameters, oil psi isnt one of them.

 

So on my 2004 any idea what's normal according to the algorithm driving the dash indicator?

Like I said, I thought is used to idle around the 40 mark and go right at speed. Now it's idling well left (though not in the "red") and swinging right of center when the RPMs are up only. This is with the engine well warmed up. If it WERE low what could that mean? I'll check oil level next but I just changed it. btw - I could only find 15w-40 instead of the 10W-30 I had been running...

 

The algorithm uses engine load, engine temp, air temp, rpm, etc to determine "normal pressure"..

Have you had the truck flashed lately?

 

hmmm... It was in for service and I declined the reverse-honk flash. I don't think they did anything else. It is colder here... Guess I'll ignore it for a while.

 

How fresh is your last oil change? I've had vehicles show a bit lower than normal as oil change time came up and viscosity was waning. It actually was a handy reminder.

Don't care to comment on the silly algorithm method . They use it on the volt gauge too. Gotta wonder what a real guage would cost.

Cya

 

Missed the "just changed it" comment, sorry . That can't be it. The heavier oil should raise the pressure, not lower it.

Why do you run 10-30? My manual says 5W-40 dino, or syn for below 30*.

Cya

 

I have always had rigs read higher when a oil change was coming due to the full filter taking more pressure to flow...

So your voltmeter doesn't bounce with the grid heaters either huh? But after the grid heaters cycle the voltmeter cycles with the voltage reading on my scan tool???

 

I have a guage on mine. When warm at idle it reads 1.5 BAR. When cold its between 4.5 and 5 BAR. I think 5 BAR = 80PSI.

 

I thought I picked 10W-30 off a chart in my manuals (gotta find that manual).
I used 15W-40 this time because it's all I could find.

I think I was just paying closer attention to the gauges because my "lamp out" indicator lit and got my attention with the truck warm in stop/go traffic. Watching again I notice that the initial (cold) pressure is over 40 immediately but falls as the truck warms up. Sounds normal based on this discussion - so I'm happy - guess I didn't notice it. (btw the oil is fresh fill, at proper level, not even blacked up yet, still honey gold on the stick)

 

First, check your oil level asap. Second, 10w30?????????

I hope not...

I run 25psi hot idle. 60-65psi at 65mph. Autometer gauge. 5w40 Schaeffer synthetic.

 

As far as him using 10w30 IIRC some of the older engines called for 10w30 oil to be used in the wintertime. So as long as the oil is made to run in a diesel engine he should be Ok. If I understood my 2006 owners manual correctly if you use 5w oil it has to be synthetic. So if you use 5w dino oil its a no no at least it is for an 06 engine.