oil pressure starts at 70 to 80 psi then gradually over 40 min goes to 20, there is fluctuation to throttle during warm up but then the pressure drops and will set off the stop engine alarm. If the engine is restarted after 1 minute the oil pressure returns to normal. oil level is normal. new oil and filter.
low oil pressure 2005 4.2l
wilfalso
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oil pressure starts at 70 to 80 psi then gradually over 40 min goes to 20, there is fluctuation to throttle during warm up but then the pressure drops and will set off the stop engine alarm. If the engine is restarted after 1 minute the oil pressure returns to normal. oil level is normal. new oil and filter.
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20,262 Posts
As there is no oil pressure gauge on the Touareg dashboard, how and where are you measuring the pressure?
I wish I had more knowledge on the V8 oil pump, but so far I have had no need. However...
The older Subaru engines ran into a similar situation. In the Subaru design, the oil pump was attached to the side of the engine block. The seal was via o-rings. It was the opposite, in that the seals were leaking when cold.
A quick search thru the audi forums (audi used the 4.2 a lot longer) mentions the oil pump is strong, but I did see a post mentioning that some older 4.2 had had o-rings around the oil pump that could harden, leading to loss of oil pressure when hot.
The older Subaru engines ran into a similar situation. In the Subaru design, the oil pump was attached to the side of the engine block. The seal was via o-rings. It was the opposite, in that the seals were leaking when cold.
A quick search thru the audi forums (audi used the 4.2 a lot longer) mentions the oil pump is strong, but I did see a post mentioning that some older 4.2 had had o-rings around the oil pump that could harden, leading to loss of oil pressure when hot.
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70 Posts
this is the spec.With the engine at operating temperature at 2000 RPMs it should be 3.0 - 5.5 bar, above 2000 RPMs it should not exceed 7.0 bar.
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20,262 Posts
1 bar = 14.5 psi
I was wondering if it could be the oil pressure relief valve? I think it is in the oil filter housing. I was thinking about changing the oil pump but also heard they were bulletproof. The thing that really baffles me is I can drive the car for 45minutes and the oil pressure fluctates from 70 to 50 psi according to throttle. As the oil warms up to a maximum of 200 it still fluctuate at a lower pressure. Finally the pressure settles at about 20 and no longer moves then it drops below 20 and the stop engine light come on. If I turn off the engine oil pressure returns to about 50 psi and then gradually diminishes
I looked, but did not find much new. A few reports of problems when using non oem quality oil filters. A few that replaced the oil pump and fixed it, a few that replaced the oil pump and did not fix it. Many many reports of bad sending units, which is not your problem.
With this, there is no modern diagnostics to help. This is a pure, 100% mechanical, figure it out by the seat of your pants problem.
I came across this novel post. http://www.clubtouareg.com/forums/f43/oil-pressure-problem-84043.html
Good luck and keep us posted.
With this, there is no modern diagnostics to help. This is a pure, 100% mechanical, figure it out by the seat of your pants problem.
I came across this novel post. http://www.clubtouareg.com/forums/f43/oil-pressure-problem-84043.html
Good luck and keep us posted.
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70 Posts
you are not mentioning rpm.
There has been some good news with the low pressure issue. The issue was that the pressure was fine at startup and gradually decreased until it reached alarm point. At first it was possible to use the throttle to increase pressure but as the pressure decreased this was not possible.
The Touareg was in the shop for a front diff change. It was decided to remove the oil pan and have a look. The theory was that the engine was slugged up and this was the root of the low pressure issue. there was very little in the oil pan but some obstruction on the intake.
Everything was put back together with new Moly 5 40 and filter. On the way home after about 20 min the low oil pressure warning came on. When I got home I looked into additives as it was still thought it may be a sticky valve or other sludge issue. I added 2 11 oz cans of wynns Engine tune up. After about 3 hours I went for a drive and the results were amazing. The drive lasted about 40 minutes on back roads, my wife drove and I watched the oil pressure gauge. The pressure remained stable and moved in range to engine speed. When stopped the pressure stayed at 23PSI and increased to about 50 at 2000 rpm.Oil temp was 200 deg and water was at 90.We have gone on 3 drives since and everything appears normal. I don't know if it is coincidental or the wynns worked but for now fingers are crossed.
The Touareg was in the shop for a front diff change. It was decided to remove the oil pan and have a look. The theory was that the engine was slugged up and this was the root of the low pressure issue. there was very little in the oil pan but some obstruction on the intake.
Everything was put back together with new Moly 5 40 and filter. On the way home after about 20 min the low oil pressure warning came on. When I got home I looked into additives as it was still thought it may be a sticky valve or other sludge issue. I added 2 11 oz cans of wynns Engine tune up. After about 3 hours I went for a drive and the results were amazing. The drive lasted about 40 minutes on back roads, my wife drove and I watched the oil pressure gauge. The pressure remained stable and moved in range to engine speed. When stopped the pressure stayed at 23PSI and increased to about 50 at 2000 rpm.Oil temp was 200 deg and water was at 90.We have gone on 3 drives since and everything appears normal. I don't know if it is coincidental or the wynns worked but for now fingers are crossed.
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