Please Help. Bad oil pressure problem
10-23-2005, 09:44 PM
#1
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Please Help. Bad oil pressure problem Last week i was driving my 99 ss at an autocross event. The lifters started ticking and the oil pressure dropped to nearly nothing. My oil was a bit low and I was told to change the oil and that it should take care of it. So that didn't help it. I searched around and found out that oil pumps go bad on these cars regularly.
I changed the oil pump to the ls6 pump and now the oil pressure is at around 35 at idle. When it gets to WOT the oil pressure either stays the same or drops, and it never goes over 45. It gets as low 20 psi when it gets to operating temperature. It hasn't started ticking again yet, but i'm leery to drive it until I can figure it out.
I'm pretty sure the new pump o-ring went on correctly, the only other thing i'm concerned of is that the new oil pump bolts may not be torqued down to 18 ft/lbs. Can this affect the pressure that much?
Any ideas would help. I really don't have the money to go to a mechanic.
I changed the oil pump to the ls6 pump and now the oil pressure is at around 35 at idle. When it gets to WOT the oil pressure either stays the same or drops, and it never goes over 45. It gets as low 20 psi when it gets to operating temperature. It hasn't started ticking again yet, but i'm leery to drive it until I can figure it out.
I'm pretty sure the new pump o-ring went on correctly, the only other thing i'm concerned of is that the new oil pump bolts may not be torqued down to 18 ft/lbs. Can this affect the pressure that much?
Any ideas would help. I really don't have the money to go to a mechanic.
10-25-2005, 03:18 PM
#4
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Could verify the oil pressure sensor's readings by using a separate oil pressure testing tool.
The intake manifold does have to be removed to replace the oil pressure sensor.
Despite being about half of what you'd normally see, 20psi at hot idle is apparently a safe minimum, so it should probably be okay to do a bit of driving till this is fixed. (although obviously not autocross
)
Autozone could probably loan you a torque wrench to check the torque on the oil pump bolts... improperly-tightened bolts are listed as a possible cause of low oil pressure. Just to confirm, the correct amount to tighten the oil pump bolts to 25 N·m (18 lb ft).
And while we're at it, here's the other torque specs:
Tighten the oil pump screen bolt to 12 N·m (106 lb in).
Tighten the crankshaft oil deflector nuts to 25 N·m (18 lb ft).
Hopefully replacing the oil pump solved your original problem and now it's just a simple fix like that.
Also, you're supposed to use a new oil pump screen O-ring seal whenever you replace the oil pump; did you?
Here is the suggested testing procedure and possible causes of the problem:
Oil Pressure Diagnosis and Testing
Tools Required
J 21867 Pressure Gage
J 42907 Oil Pressure Testing Tool
1. With the vehicle on a level surface, run the vehicle for a few minutes. Allow adequate drain down time of 2-3 minutes and measure the oil level.
2. If required, add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
3. Run the engine briefly, 10-15 seconds, and verify low or no oil pressure on the vehicle gage or light.
4. Listen for a noisy valve train or a knocking noise.
5. Inspect for the following:
- Oil diluted by water or glycol, anti-freeze
- Foamy oil
6. Remove the oil filter and install the J 42907 .
7. Install J 21867 or equivalent to the J 42907 .
8. Run the engine and measure the engine oil pressure.
9. If the engine oil pressure is below specifications, inspect the engine for one or more of the following:
- Oil pump worn or dirty
- Oil pump-to-engine block bolts loose
- Oil pump screen loose, plugged, or damaged
- Oil pump screen O-ring seal missing or damaged
- Malfunctioning oil pump pressure regulator valve
- Excessive bearing clearance
- Cracked, porous, or restricted oil galleries
- Oil gallery plugs missing or incorrectly installed
- Broken valve lifters
Repair as necessary
10. If the oil pressure reading on the J 21867 or equivalent is within specifications, inspect for the following:
- Plugged or incorrect oil filter and/or malfunctioning oil bypass valve
- Malfunctioning oil pressure gage or sensor
Repair as necessary
The intake manifold does have to be removed to replace the oil pressure sensor.
Despite being about half of what you'd normally see, 20psi at hot idle is apparently a safe minimum, so it should probably be okay to do a bit of driving till this is fixed. (although obviously not autocross
)Autozone could probably loan you a torque wrench to check the torque on the oil pump bolts... improperly-tightened bolts are listed as a possible cause of low oil pressure. Just to confirm, the correct amount to tighten the oil pump bolts to 25 N·m (18 lb ft).
And while we're at it, here's the other torque specs:
Tighten the oil pump screen bolt to 12 N·m (106 lb in).
Tighten the crankshaft oil deflector nuts to 25 N·m (18 lb ft).
Hopefully replacing the oil pump solved your original problem and now it's just a simple fix like that.
Also, you're supposed to use a new oil pump screen O-ring seal whenever you replace the oil pump; did you?
Here is the suggested testing procedure and possible causes of the problem:
Oil Pressure Diagnosis and Testing
Tools Required
J 21867 Pressure Gage
J 42907 Oil Pressure Testing Tool
1. With the vehicle on a level surface, run the vehicle for a few minutes. Allow adequate drain down time of 2-3 minutes and measure the oil level.
2. If required, add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
3. Run the engine briefly, 10-15 seconds, and verify low or no oil pressure on the vehicle gage or light.
4. Listen for a noisy valve train or a knocking noise.
5. Inspect for the following:
- Oil diluted by water or glycol, anti-freeze
- Foamy oil
6. Remove the oil filter and install the J 42907 .
7. Install J 21867 or equivalent to the J 42907 .
8. Run the engine and measure the engine oil pressure.
9. If the engine oil pressure is below specifications, inspect the engine for one or more of the following:
- Oil pump worn or dirty
- Oil pump-to-engine block bolts loose
- Oil pump screen loose, plugged, or damaged
- Oil pump screen O-ring seal missing or damaged
- Malfunctioning oil pump pressure regulator valve
- Excessive bearing clearance
- Cracked, porous, or restricted oil galleries
- Oil gallery plugs missing or incorrectly installed
- Broken valve lifters
Repair as necessary
10. If the oil pressure reading on the J 21867 or equivalent is within specifications, inspect for the following:
- Plugged or incorrect oil filter and/or malfunctioning oil bypass valve
- Malfunctioning oil pressure gage or sensor
Repair as necessary
10-26-2005, 05:40 PM
#7
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Sounds like oil sloshed away from the pickup during the event, and maybe took a bearing with it. Check oil level before autoXing, might want to overfill a little beforehand.
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10-27-2005, 02:34 PM
#9
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Originally Posted by XLR8TOR
Sounds like oil sloshed away from the pickup during the event, and maybe took a bearing with it. Check oil level before autoXing, might want to overfill a little beforehand.
10-27-2005, 07:59 PM
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The pick up tube is bolted to the block inside the oil pan. I had a Camaro one time that the pick up was plugged up from sludge and what I did was pour a can of carb cleaner, no, not the kind in the spray can, the kind that you dip carb parts in, anyway, I soaked the pickup w/ that solvent in the bottom of the pan overnight and then drained it out. Whatever you do, don't start the car w/ this stuff in there. It seem to work since the oil pressure came back. How long it lasted? I don't know the car was traded in a week later.
