Post by AmunRoo on Jun 12, 2018 22:32:45 GMT -6
I changed the oil pressure sensor because I was getting a low oil pressure light whenever I came to a stop or was at idle. The engine ran fine and the oil was moving without any issues. The engine wasn't overheating and there was no knocking or any strange noises coming from the motor. Bought the AC Delco oil pressure sensor, put it in and I'm still getting the same issue. I did read about an issue with the harmonic balancer Bolt causing the low oil warning problems on the Northstar engines. Anyone know if there's any truth to this? This is a TSB for the 4.6 but it also applies to the 4.0
"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."
"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."
