oil pressure relief valve

[Jasperse]

I have a 1995 Aurora. It has turned on the low oil pressure warning. Spoke to the dealer and he suggested checking the harmonic balancer bolt and the oil pressure relief valve. The harmonic balancer it tightened just fine. Problem being "where is the pressure relief valve"? Also the dealer recommened adding an additional 12 qts. of oil and starting the car and reving it to 3500 rpm to flush out the pressure relief valve, as it may have debris blocking it. Has anyone ever tried that??? Any additional suggestions?

Thanks

[Jasperse]

Originally Posted by Jasperse

I have a 1995 Aurora. It has turned on the low oil pressure warning. Spoke to the dealer and he suggested checking the harmonic balancer bolt and the oil pressure relief valve. The harmonic balancer it tightened just fine. Problem being "where is the pressure relief valve"? Also the dealer recommened adding an additional 12 qts. of oil and starting the car and reving it to 3500 rpm to flush out the pressure relief valve, as it may have debris blocking it. Has anyone ever tried that??? Any additional suggestions?

Thanks

I recieved an email from Automotiveforums.com team:
Here is the message that has just been posted:
***************
Is there even room for an extra 12 quarts of oil?
The only pressure relief valve in the index in my manual is in the trunk, and nothing to do with oil pressure.
Does your dealer have a sense of humor?
***************

There may be other replies also, but you will not receive any more notifications until you visit the board again.

Yours,
Automotive Forums .com team


This is the TSB:

Engine - Loss of Oil Pressure/Lack of Power/Oil, MIL ON

File In Section: 6 Engine

Bulletin No.: 47-61-32B

Date: March, 1996

Subject:
Lack of Power, Loss of Oil Pressure
(Check Harmonic Balancer Bolt Torque and Flush Oil Pump Relief Valve)

Models:
1993 Cadillac Allante
1993-96 Cadillac Eldorado, Seville
1994-96 Cadillac Concours
1996 Cadillac Sedan DeVille
with 4.6L Engine (VINs Y, 9 - RPOs LD8, L37)
1995-96 Oldsmobile Aurora
with 4.0L Engine (VIN C - RPO L47)

This bulletin is being revised to add clarification to correction. Please discard Corporate Bulletin Number 47-61-32A (Section 6 - Engine).

Condition

Some owners may comment on low oil pressure which may display a "Low Oil Pressure" message and/or a "Malfunction Indicator Lamp" (Service Engine Soon) telltale. Vehicle owners may comment that these telltale messages illuminate at engine speeds of 1000 rpm and above.

Cause

Lack of oil pressure may be caused by:

^ Particles from the manufacturing process sticking the oil pump relief valve, not allowing the valve to seal to its seat which does not allow the pump to prime.

^ A loose harmonic balancer bolt which will result in the oil pump not turning.


Correction

Ensure the harmonic balancer bolt is tighten to spec. The correct torque value for this bolt is 60 N.m (44 lb ft) plus 120°for 1993-95 engines with an M18 bolt and 50 N.m (37 lb ft) plus 120°for 1996 engines with an M14 bolt.

Notice : A small number of 1995 engines were built with crankshafts equipped with the M14 bolt. Identify the size of the bolt to determine the proper torque specification.

If the bolt is to specification, the cause of the low oil pressure is internal to the pump.

To remove particles from the relief valve in the oil pump, perform the following procedure:

1. Add an ADDITIONAL 10 to 12 quarts (liters) of engine oil to the engine. This will immerse the pump completely in oil.

2. Start the engine and repeatedly open the throttle (rev the engine) from idle to 3500 rpm. This will allow the pump to prime; cycling the relief valve forces any debris from the relief valve.

Important : Do not operate the engine above 3500 rpm. Doing so will aerate the engine oil and/or force excess engine oil into the PCV system. DO NOT DRIVE THE VEHICLE while the additional oil is in the engine.

After the engine has sufficient oil pressure, any valvetrain noise associated with this low oil pressure condition should not be evident upon restarting the vehicle and the low oil pressure and malfunction indicator lamp (service engine soon) messages should not remain illuminated.

3. After engine has sufficient oil pressure, drain the crankcase. Reinstall the engine oil pan drain plug.

4. Add 7 quarts of engine oil and check the oil level. Make sure the vehicle is on a level surface and the engine operating temperature is 1OO°C when checking the oil level with the engine stopped for 15-20 seconds.


Warranty Information

For vehicles repaired under warranty, use:

Labor Operation Labor Time

J0989 0.5 hr

[Sweet William]

It's very rare for the NorthStar to have any oil pressure problems other that the two described above. The overfill does work to cycle the releif valve.

[Jasperse]

Sweet William....do I really add an additional 12 qts? that seems a little scary

[Sweet William]

Ten should be enough. If it does not clear try again after the pump has sat submerged for 24 hours to make positively sure that the overfill has a chance to seep into the pump and prime it. The failure mode of the stuck open relief valve just doesn't allow the pump to prime due to the fact that the oil cannot get pulled to the pump as the pump is recirculating air thru the relief valve..if it is stuck open. There is no way this failure mode can prevent priming if the oil level is above the level of the pump. So...if this doesn't work then there is another problem


Is the problem constant or did it happen once when the motor was hot idling in gear? When you start it up what does you read out say?

[Jasperse]

I've had no previous problems, but yesterday I got off the Hwy and the warning came on. Stopped right away. The readout stills says "low oil pressure", and will not display the PSI readout. I am adding 10 qts. making a total of 18 qts. Hoping for the best.

[Sweet William]

While the motor is still over filled you can also remove the oil filter and bump the motor over to see if pump is working. Remove filter, if you do it with filter lose oil will shoot out all around filter instead of just down.

It could also be the oil pressure warning switch is ready for replacement. just look for the switch next to the oil filter. Replace it with an OEM part as the OEM parts have a different switch point than the generic ones from the auto parts store. Not unusual to have one of those start to give an intermittant warning light at high miles as the switch is getting old......

[Jasperse]

Thanks Sweet William for all your help. Over filling took care of the problem. Had to rev it up several times but bingo instant pressure. That was a cheap fix compared to oil pump replacement.

[Drama]

Jasperse....please advise. What is exactly that you did? Just added additional 10 quarts of oil? The thought is scary, but I'll try anything because my "low oil pressure" messages are driving me crazy. I have tried to replace oil pressure sending unit, but it did not help

[Jasperse]

I did just that with great hesitation....Added 10 qts. held my breath and started the car, the warning continued to flash and reved the car about 8-10 times and bingo car started to register oil pressure. I did not drive the car with low oil pressure. Immediately pulled over and towed it home. The car has ran great ever since and no more "oil pressure" problems. Good luck, seemed an easy fix.

[Drama]

My '99 normaly reads the presure when started or when running. However, occasionaly (on small inclines, i.e. when I turn from the street onto the parking lot of the grocery store) pressure drops to 0, and the warning "low oil pressure" comes on. I have been driving like this for the last 4-5 months, and have not experienced any engine related problems. But there is that "little bug" in my head that is bothering me. I'll fill it up with additional 10 quarts then, and...we'll see. By the way...where did you get this tip? Some trusted source?

[Drama]

Jasperse...please see the comment I saw under "Oil Pressure Drop" topic.

"Adding 10 extra quarts of oil to a full oil filled engine and running the engine is guaranteed to break something. After adding the extra oil the crank-shaft would be submerged in oil and the load it would put on the crank-shaft would ensure damaging some internal engine components. Try fitting a mechanical oil pressure gage, in addition to the electronic sending unit, to get an accurate reading. At the same time inspect the wires going from the sending unit and make sure the insulation in intact"

[rodtice]

This is not guaranteed to break something when it is GM's recommended procedure and you follow it to the letter, there is an RPM limitation with this procedure and instructions to drain and not drive when complete.

[Drama]

Thanks for the encouragment rodtice...I need it.

[rlzech]

Originally Posted by Drama

Jasperse...please see the comment I saw under "Oil Pressure Drop" topic.

"Adding 10 extra quarts of oil to a full oil filled engine and running the engine is guaranteed to break something. After adding the extra oil the crank-shaft would be submerged in oil and the load it would put on the crank-shaft would ensure damaging some internal engine components. Try fitting a mechanical oil pressure gage, in addition to the electronic sending unit, to get an accurate reading. At the same time inspect the wires going from the sending unit and make sure the insulation in intact"

Hello there: I too am having the oil pressure problem with a '95 Aurora. Did your solution as posted have the long term desired result?? The methods sounds just a little strange to me, but since you tried it, I'd like to hear from you.

Thanks
Randy Zech