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  #1  
Old 09-23-2009, 07:35 PM
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Low oil pressure after filter change???

Ok really more to the story....

A couple of weeks ago I had a vacuum pump fail. I limped home and shut it down. Oil pressure was normal.

After pulling the pump, pulling out the guts and putting the shell back on, I pulled the oil pan and found all of the ball bearings and what I think was all of the other collateral damage. I checked the oil pump screen and it was clean. I pulled it off and checked it.

I put in a new oil filter and new oil (store brand as I was going to use it to flush out the system and change it again this weekend).

Well now the oil pressure is low. About 1 (slightly less) at idle and about 2+ at 60 MPH.

Is there any chance that the filter could be causing this? Could I have pinched the oil pressure line?

Thoughts?

Thats a little too low for my comfort.

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1983 300D Turbo 260,000 Miles
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1998 Ford Expedition 5.4l (fer Haulin'!) 145,000
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  #2  
Old 09-23-2009, 07:51 PM
92 300D 2.5L OBK #59
 
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I'd go the easier route first and replace the 2 rubber washers on the oil canister lid rod.

Rule out easy stuff first. Your oil pump is pumping oil. I think min is .5 bar at idle and 2.5 and above above 2400 RPM.
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Old 09-23-2009, 07:55 PM
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I believe spec is .3 bar at idle, and atleast 3 bar by 3000 RPM.

What brand of filter did you use?
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  #4  
Old 09-23-2009, 08:52 PM
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I wouldn't drive it with that kind of oil pressure until the problem was solved. Not sure about the cause?
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Old 09-23-2009, 09:02 PM
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#20 and #21 O-rings are at the very end of that stem on the Oil Filter. Oil that leaks buy will go to the Oil Pan.
Despite the fact that one part of the Stem is smaller than the other the stock size for both O-rings is - 6x10x2mm

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Last edited by Diesel911; 09-23-2009 at 09:13 PM.
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Old 09-23-2009, 09:17 PM
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Quote:
Originally Posted by 79Mercy View Post
I believe spec is .3 bar at idle, and atleast 3 bar by 3000 RPM.

What brand of filter did you use?
Well it is within spec. But it was much higher, about 2+ at idle.

The filter is a Mahle.
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Fuquay-Varina, NC
1979 300D
1983 300D Turbo 260,000 Miles
1984 300D Turbo 345,000 Miles (sons car)
OBK #31
1998 Ford Expedition 5.4l (fer Haulin'!) 145,000
1973 19' SeaRay with 115 Mercury TOWER OF POWER!
Club Car Golf Cart 36V
Ex toys:
1967 Mustang 289 (First Car)
Fiat 124TC
1975 Honda CVCC
1980 Audi 5000 Turbo
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Old 09-23-2009, 09:17 PM
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Quote:
Originally Posted by Diesel911 View Post
#20 and #21 O-rings are at the very end of that stem on the Oil Filter. Oil that leaks buy will go to the Oil Pan.
Despite the fact that one part of the Stem is smaller than the other the stock size for both O-rings is - 6x10x2mm
If you want a local source of the 6x10x2 O-rings Autozone sells a metric O-ring assortment for around $7. It has 24 of the above O-rings and one of the sizes also fits the Lower O-ring on the Secondary Fuel Filter bolt.
see thumbnail
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Old 09-25-2009, 03:11 PM
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Well it appears that those rubber washers are real hard. I tried putting in some rubber o rings but I dont think that worked. I am still at the lower oil pressure. I may just try replacing the oil filter and try to see what is in the filter case. Any other suggestions? The car seems to run OK and no weird noises. Still afraid to drive it at this pressure.
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NC Benz
Fuquay-Varina, NC
1979 300D
1983 300D Turbo 260,000 Miles
1984 300D Turbo 345,000 Miles (sons car)
OBK #31
1998 Ford Expedition 5.4l (fer Haulin'!) 145,000
1973 19' SeaRay with 115 Mercury TOWER OF POWER!
Club Car Golf Cart 36V
Ex toys:
1967 Mustang 289 (First Car)
Fiat 124TC
1975 Honda CVCC
1980 Audi 5000 Turbo
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Old 09-25-2009, 08:38 PM
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What Brand of Oil filter did you use just before the Oil pressure drop?
And, when you changed your Oil did the new Oil have a lower viscosity than the old one?

It would be nice to check the Oil Pressure with a test gauge; but, there is no easy way to tap into the oil pressure.

The main thing is the Oil Pressure is remains in a safe range.

In the drawing of the Oil Filter #19 is a Check Valve. I do not know how to access that check Valve but one of the Members said that he found a piece of Cotton in his check valve holding it open.
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Old 09-25-2009, 09:44 PM
92 300D 2.5L OBK #59
 
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If your within the specs called for I'd run it until it fell out of specs. Did you switch grades of oil?
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  #11  
Old 09-26-2009, 02:14 AM
Craig
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Quote:
Originally Posted by bobodaclown View Post
If your within the specs called for I'd run it until it fell out of specs. Did you switch grades of oil?
2 bars at 60 mph is not within spec and is not normal for any oil.
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  #12  
Old 09-27-2009, 08:42 AM
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Quote:
Originally Posted by Diesel911 View Post
What Brand of Oil filter did you use just before the Oil pressure drop?
And, when you changed your Oil did the new Oil have a lower viscosity than the old one?

It would be nice to check the Oil Pressure with a test gauge; but, there is no easy way to tap into the oil pressure.

The main thing is the Oil Pressure is remains in a safe range.

In the drawing of the Oil Filter #19 is a Check Valve. I do not know how to access that check Valve but one of the Members said that he found a piece of Cotton in his check valve holding it open.
I was using a MANN Filter before. On a whim, I took out the old filter and put a MANN in. No pressure change. I also added some O Rings to the oil filter rod to ensure that there wasnt any leakage.... no change. So It appears that it is not the filter.

The only other thing I did was to change oil (15W40, but a store brand) and I did pull the oil pan and the rubber oil pump pickup to make sure the screen was clean. Perhaps the rubber pickup just isnt seated correctly and is sucking air? Or perhaps there is something caught in the oil pressure gauge line?

ARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRGGGG (there I feel better)
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NC Benz
Fuquay-Varina, NC
1979 300D
1983 300D Turbo 260,000 Miles
1984 300D Turbo 345,000 Miles (sons car)
OBK #31
1998 Ford Expedition 5.4l (fer Haulin'!) 145,000
1973 19' SeaRay with 115 Mercury TOWER OF POWER!
Club Car Golf Cart 36V
Ex toys:
1967 Mustang 289 (First Car)
Fiat 124TC
1975 Honda CVCC
1980 Audi 5000 Turbo
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  #13  
Old 09-27-2009, 09:25 AM
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Partial blockage would not cause a low reading IMHO.
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  #14  
Old 09-27-2009, 09:36 AM
92 300D 2.5L OBK #59
 
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Good luck. Hope you find your issue. Sorry it wasn't something easy.
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  #15  
Old 09-27-2009, 09:52 AM
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Quote:
Originally Posted by NC Benz View Post
Well now the oil pressure is low. About 1 (slightly less) at idle and about 2+ at 60 MPH.

Is there any chance that the filter could be causing this? Could I have pinched the oil pressure line?

Thoughts?

Thats a little too low for my comfort.
I do not believe that any oil or filter can result in 2 bar at 2500 rpm on a 617.

Therefore, the only remaining possibility is some slight damage to the oil pump due to small pieces of metal permeating the screen. The damage to the pump is slight and the resulting oil pressure drop is observable. However, running it at that pressure for an extended period of time is not recommended.

The recommendations regarding the o-rings will not affect the outcome.

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