Engine/Transmission (1998.5 - 2002) Oil pressure at idle

[Wyomingcowboy]

Got a questions for you guys - what pressure should I see at warmed up idle? I get the usual high pressure on cold startups but after everything warms up, the idle pressure drops to well below 40. It is never at zero, and it climbs up to 60 - 80 psi area at hwy speeds. I rebuilt this thing last spring and used the same oil pump and don't remember the pressure being this low. Is my pump going bad? I had a "94 chevy witht he 6. 5 in it and it did the same thing. Maybe I'm just paranoid?

thanks

 

[Wyomingcowboy]

Here's a pic of my typical warm idle pressure reading.

 

[rjrkihap]

Hey Cowboy,



I see the exact same thing. I've also read that the factory gauge is more of an approximation of actual oil pressure. I'm guessing the actual pressure is more than what the factory gauge is showing.



Ron

 

[JMetzger]

My 02 reads the same thing as yours at idle. Has read the same for 89,000 miles. Hope this helps.

 

[cmills]

Same here.

 

[JCyrbok]

Here's a pic of my typical warm idle pressure reading.

mine too



J-

 

[Moe]

Mine is the same too.

 

[Joe Mc]

186k same thing. If you are concerned and want to check w/mechanical gage you can access on top of oil filter housing and observe at idle and higher rev.

 

[AWeiman]

mine is the same to. i believe the owners manual says no less than 10psi at idle and no less than 30psi under a load so you should be good to go.

 

[PBJ2500CTD]

Same as I see on my '02...

 

[Wyomingcowboy]

I'm feelin alot better now... . thanks. I do want to buy a fuel pressure gauge AND an oil pressure gauge for my shop and multiple vehicles bothe gas and diesel. Any suggestions? We get a pretty good deal with Snap On and I love their service. Any other ideas?

 

[drag racer]

i recently had a real gauge on mine, and the factory "guage" read 10-20 psig low by my estimation. don't worry about it

 

[jeepit]

Mine reads the same... .

 

[Jerky]

Mines the same as well@90000+

 

[PVanderlugt]

keep in mind that the factory oil pressure gauge on the later models don't read anything, per the factory manual, as long as the switch sees 7psi or more it is good to go, any movement of the needle is the computers estimate of what the oil pressure "should" be based on coolant temp, rpm etc. With that in mind all of our late model rams should have the exact same readings under the same conditions, regardless of miles or wear.
Pete

 

[BDaugherty]

Here's what my '01 factory service manual has to say about the oil psi gauge:



OIL PRESSURE GAUGE



DESCRIPTION



An oil pressure gauge is standard equipment on all

instrument clusters. The oil pressure gauge is located

in the upper right quadrant of the instrument cluster,

above the fuel gauge. The oil pressure gauge consists

of a movable gauge needle or pointer controlled

by the instrument cluster circuitry and a fixed 90

degree scale on the cluster overlay that reads left-toright

either from 0 kPa (0 psi) to 758 kPa (110 psi).

An International Control and Display Symbol icon for

“Engine Oil” is located on the cluster overlay, directly

below the highest graduation of the gauge scale. The

oil pressure gauge graphics are white against a black

field except for a single red graduation at the low

end of the gauge scale, making them clearly visible

within the instrument cluster in daylight. When illuminated

from behind by the panel lamps dimmer

controlled cluster illumination lighting with the exterior

lamps turned On, the white graphics appear

blue-green and the red graphics appear red. The

orange gauge needle is internally illuminated. Gauge

illumination is provided by replaceable incandescent

bulb and bulb holder units located on the instrument

cluster electronic circuit board. The oil pressure

gauge is serviced as a unit with the instrument cluster.



OPERATION



The oil pressure gauge gives an indication to the

vehicle operator of the engine oil pressure. This

gauge is controlled by the instrument cluster circuit

board based upon the cluster programming and electronic

messages received by the cluster from the

Powertrain Control Module (PCM) over the Chrysler

Collision Detection (CCD) data bus. The oil pressure

gauge is an air core magnetic unit that receives battery

current on the instrument cluster electronic circuit

board through the fused ignition switch output

(st-run) circuit whenever the ignition switch is in the

On or Start positions. The cluster is programmed to

move the gauge needle back to the low end of the

scale after the ignition switch is turned to the Off

position. The instrument cluster circuitry controls

the gauge needle position and provides the following

features:

² Engine Oil Pressure Message - The instrument

cluster circuitry restricts the oil pressure gauge

needle operation in order to provide readings that

are consistent with customer expectations. Each time

the cluster receives a message from the PCM indicating

the engine oil pressure is between about 6. 9 kPa

(1 psi) and 137. 9 kPa (20 psi) for gasoline engines, or

55 kPa (8 psi) and 58. 6 kPa (8. 5 psi) for diesel

engines, the cluster holds the gauge needle at a point

about 11 degrees above the low end of normal increment

on the gauge scale. Each time the cluster

receives a message from the PCM indicating the

engine oil pressure is between about 517. 1 kPa (75

psi) and 755 kPa (109. 5 psi) for gasoline engines, or

551. 6 kPa (80 psi) and 755 kPa (109. 5 psi) for diesel

engines, the cluster holds the gauge needle at a point

about 7. 4 degrees below the high end of normal

increment on the gauge scale. When the cluster

receives messages from the PCM indicating the

engine oil pressure is between about 137. 9 kPa (20

psi) and 517. 1 kPa (75 psi) for gasoline engines, or

58. 6 kPa (8. 5 psi) and 551. 6 kPa (80 psi) for diesel

engines], the gauge needle is moved to the actual

pressure position on the gauge scale.

² Engine Oil Pressure Low Message - Each

time the cluster receives a message from the PCM

indicating the engine oil pressure is below about 6. 9

kPa (1 psi) for gasoline engines, or 55 kPa (8 psi) for

diesel engines, the gauge needle is moved to the 0

kPa (0 psi) graduation at the far left (low) end of the

gauge scale, the check gauges indicator is illuminated,

and a single chime tone is generated. The

gauge needle remains at the low end of the scale and

the check gauges indicator remains illuminated until

the cluster receives a message from the PCM indicating

that the engine oil pressure is above about 6. 9

kPa (1 psi) for gasoline engines, or 55 kPa (8 psi) for

diesel engines, or until the ignition switch is turned

to the Off position, whichever occurs first. The cluster

will only turn the check gauges indicator lamp on

in response to an engine oil pressure low message if

the engine speed message is greater than zero.

² Engine Oil Pressure High Message - Each

time the cluster receives a message from the PCM

indicating the engine oil pressure is above about 755

kPa (109. 5 psi) for gasoline or diesel engines, the

gauge needle is moved to the 758. 4 kPa (110 psi)

graduation at the far right (high) end of the gauge

scale. The gauge needle remains at the high end of

the scale until the cluster receives a message from

the PCM indicating that the engine oil pressure is

below about 755 kPa (109. 5 psi) for gasoline or diesel

engines, or until the ignition switch is turned to the

Off position, whichever occurs first.

² Message Failure - If the cluster fails to receive

an engine oil pressure message, it will hold the

gauge needle at the last indication until a new message

is received, or until the ignition switch is turned

to the Off position, whichever occurs first.

² Actuator Test - Each time the cluster is put

through the actuator test, the gauge needle will be

swept to several calibration points on the gauge scale

in a prescribed sequence in order to confirm the functionality

of the gauge and the cluster control circuitry.

The PCM continually monitors the engine oil pressure

sensor to determine the engine oil pressure. The

PCM then sends the proper engine oil pressure messages

to the instrument cluster. For further diagnosis

of the oil pressure gauge or the instrument cluster

circuitry that controls the gauge, (Refer to 8 - ELECTRICAL/

INSTRUMENT CLUSTER - DIAGNOSIS

AND TESTING).

If the instrument cluster turns on

the check gauges indicator due to a low oil pressure

gauge reading, it may indicate that the engine or the

engine oiling system requires service. For proper

diagnosis of the engine oil pressure sensor, the PCM,

the CCD data bus, or the message inputs to the

instrument cluster that control the oil pressure

gauge, a DRBIIIt scan tool is required. Refer to the

appropriate diagnostic information

 

[AH64ID]

I am not sure about difference, but I bet the oil pump is the same one between 2nd and 3rd gen.



With my aftermarket gauge I see 20psi at warm idle, and 60 psi warm cruise. Up to about 80 when cold and above 1500 rpms.

 

[WalterJ]

Wow, thanks. So it's not a pressure xmttr, but merely some empirical estimate. I'm showing the same "low" pressure. I'm chipped up w/Banks & the PDA, but see that 2 fuel press. & an oil press. gauge would be really nice to monitor RV'g.



'04. 5, 141K, 3500 SRW

 

[AH64ID]

Yep, the only thing is a 6psi switch.

 

[Lone Watie]

Try again below...