Oil pressure question

[sloanxx]

I have a 99 2500 that I got used from a Dodge dealer that came equipped with the Banks turbo sysytem and the 4" exhaust. I made sure the turbo was covered under their used vehicle warranty and away I went. I noticed fluctuating oil pressure the other morning and when I started asking questions of the teamsters at work I realized that I know nothing about diesel engines and one of them suggested I check out this site. The question is this, I started my truck the other morning and let it warm up for a bit but it definitely wasn't at 140 degrees. I noticed that at idle the oil pressure was in the middle where it always is but when I would accelerate it would jump to the higher end of the highlighted oil pressure gauge. I apologize for the lack of hard data but those gauges aren't the most informative. Now is this a result of not letting the truck warm to operating temp, or something else?

 

[chuck3]

Some of the guys have had some problems with the sender units. Might want to do a search for some older threads on that.

 

[sloanxx]

Sorry about that I should have just done the search feature first. How hard is it to change that sender at home?

 

[PRout]

Just for something to compare to.



According to my Isspro EV gauge, it shows up to 85psi when the motor is cold at about 35-40* outside. It idles cold at about 60psi. I dont care for that, as I cringe thinking about all those seals in the motor being pushed hard.



On a cold start in about 55* the pressure goes to 70-75psi, idles at about 55psi.



No matter what the outside air temp is, at cruise w/ a fully warmed motor it runs about 58-63psi (depending on rpms).



at idle w/ fully warm motor, it drops down to as low as 21-23psi. That seems low, but someone posted on this site that 20-30psi at idle is normal (ill have to look it up in the service manual).



I do have bypass oil filtering, but didnt notice much change, since I run 2 filters in series, its not much drop.



Hope that helps. like the guys say, wouldnt hurt to replace the stock sender, or maybe better just get a set of gauges and include a good oil pressure gauge. They really help get more feel for whats normal & whats not.

 

[jpolston]

It is normal for the oil pressure to increase when the engine is below normal operating temperature due to the increased viscosity of the cooler oil. Also, the oil pressure will increase as the RPM's increase, the oil pump is a positive displacement gear pump and the volume pumped is a direct function of the driven speed. I would say what you have described sounds normal.

 

[sloanxx]

Okay so I did a little road test on my own this evening and between this and my warm up proceedure post I think I have almost solved my problem. It seems that now until the engine hits operating temps it fluctuates from (at idle) the 40 mark up to near the outside of the marked off area of the stock gauge (under acceleration). Once at operating temp it fluctuates between slightly below the 40 mark to a little bit above the 40 mark even under heavy acceleration. Does this sound normal? Many thanks to everyone that answered here and my warm up post for the help.

 

[Dave MacArthur]

Sloan-



That sounds completely normal. I have a '99 that I bought new. I now have almost 70K on it and mine does the exact same thing.



Dave.

 

[THerman]

All of these readings appear normal to me.

As far as ease of replacement... Piece of cake... but having the socket is the key... .

32mm(1-1/4") semi-deep well... I got an axle-nut socket at autozone. Took all of 5 mins.



As long as you are seeing fluctuation in gauge readings I'd say your sender is probably working correctly... BUT if it is always right near top scale... . It is DEAD!! The stupid programmers have the computer keep it in the normal range... but you won't see it vary with rpm.



Tod

 

[sloanxx]

Okay just wanted to follow this up after the dealer checked it out so here goes. Apparently it is normal for the check gauge light to come on until the engine has oil pressure and then cut off. Also the oil pressure is supposed to be at 60 lbs until the engine reaches operating temps and then drop back into the 40 lbs. region. Just wanted post a fllow up incase someone else has the same question later and does a search. Thanks again for all the help.

 

[THerman]

Sloan,



Glad to hear things are ok.



On your sig, When in danger, when in doubt, run in circles, scream and shout. , and if that fails prepare for the grizzly to eat you!:{



Have Fun,



Tod