Oil Filter Return Pipe - PeachParts Mercedes-Benz Forum

BrierS · #1 10-28-2005, 06:25 AM

Since taking ownership of my '87 300TD I have performed regular oil/filter changes using M1. At the first oil & filter change I found the o'rings on the return pipe to be bad so I replaced them. Now I do this with each change. My nagging question is regarding the pipe itself . . . it does not seem to allow a reasonable (highly subjective) rate of airflow through it when I clean it. Does anyone know if these pipes actually go bad? Is there some type of spring/valve inside? Should I simply replace the pipe next (within a week or so) oil & filter change?
Steve

SD Blue · #2 10-28-2005, 12:16 PM

There is a check valve at the bottom, in the upper oil pan. Next oil change, run some motor flush through it after you pull the drain plug. It gets sludge build-up from a combination of dirt, oil and worn/broken air cleaner mounts.

Hatterasguy · #3 10-28-2005, 12:19 PM

I sprayed mine out with some carb cleaner awhile back. I didn't notice a difference in oil pressure so I don't know if a I gianed anything.

SD Blue · #4 10-28-2005, 01:11 PM

Quote:

Originally Posted by Hatterasguy

......... I didn't notice a difference in oil pressure so I don't know if a I gianed anything.

Since it is a drain, I wouldn't think there would be any change in oil pressure. However, there should be less oil in the air cleaner assembly now.

sixto · #5 10-28-2005, 01:24 PM

I'm lost. What's an oil filter return pipe?

Sixto
87 300SDL

BrierS · #6 10-28-2005, 07:16 PM

Quote:

Originally Posted by sixto

I'm lost. What's an oil filter return pipe?

Sixto
87 300SDL

For me, I'm referencing what the Haynes manual calls it . . . it is the tube/pipe that the oil filter slides over. Small hole in the upper portion that you are supposed to be able to blow air through. I have never been able to get more than a trickle through mine. That, I think, is a problem. What say the masses?
Thanks,
Steve

Hatterasguy · #7 10-28-2005, 09:35 PM

Quote:

Originally Posted by SD Blue

Since it is a drain, I wouldn't think there would be any change in oil pressure. However, there should be less oil in the air cleaner assembly now.

No not with the 603's their is a crankcase gas seperator, their should be zero oil on the filter.

SD Blue · #8 10-28-2005, 11:44 PM

After reviewing this post, I realized we are talking about two entirely different things. Hopefully, you will allow me to bow out gracefully. I admit to no experience with the 603.

sixto · #9 10-28-2005, 11:51 PM

Quote:

Originally Posted by Hatterasguy

No not with the 603's their is a crankcase gas seperator, their should be zero oil on the filter.

Not only that, the valve cover vent plumbs in just before the turbo. The air filter is upstream of that point with the airflow meter in between.

Sixto
87 300SDL

t walgamuth · #10 10-28-2005, 11:54 PM

i thought the theigh bone was connected to the hip bone and the hip bone was .....

sorry it is getting late. good night.

tom w

sixto · #11 10-28-2005, 11:56 PM

Steve, I guess the SDL is different from the TD. IIRC when I remove the filter, there is nothing in the cavity I can blow into except for the cavity itself. There is a shaft with seals attached to the cover but it's a solid shaft, not a pipe. Does FastLane have a picture of this pipe? My 124 Haynes manual is helping another Dieseler so I can't reference it just now.

Hattie, where is this thing you spray with carb cleaner?

Sixto
87 300SDL

BrierS · #12 10-29-2005, 05:28 AM

Though I did not find a photo yet, this is an excerpt I borrowed that may help clear up what I am referring to . . .

"When you change the oil filter on a Mercedes diesel, always check the two small o-rings at the bottom of the oil return tube attached to the filter housing cover. Replace them whenever they look damaged or brittle. Failure of these o-rings will cause oil pressure fluctuation, especially at idle. Order a supply of these from your dealer so you'll always have some on hand - just in case (Part No. 015-997-94-48)."

It is the oil return tube I am referring to. Hope this helps yet in the meantime, I will keep searching for a photo to post.
Steve

sixto · #13 10-29-2005, 01:35 PM

Steve, you hit it on the head. I always thought that was a solid shaft attached to the oil filter cover. I have new rings for it. I'll try blowing through it when I change the oil.

Thanks,
Sixto
87 300SDL

Hatterasguy · #14 10-29-2005, 07:28 PM

Sixto you just reminded me! The W124 and the W126 do have different filter stands. On the W124 the shaft isn't connected to the cover like it is on the W126.

I wonder why it must have been a clearence issue.

Lycoming-8 · #15 10-30-2005, 12:10 AM

Which way is the air flow supposed to go when checking this? Side hole to bottom hole or bottom hole up to side hole. Seems like if it was the latter, the ball check would be keeping the oil from draining back to the engine.