Oil Return Tube Leak at Junction to Oil Tank

[rinconmann]

Can some of you take a crack at these pictures of a leak above the oil tank? I would like to know what parts would be required to fix this slow oil leak from what appears to be the connection from the oil return tube and a connector point located directly above the Oil Tank. I could never figure it out so I got a florescent dye and tracked it down to the connection point using the dye. I think it is an oil return tube junction leaking. See the poor pictures, its the best I could do being under the engine bay. I need to de-grease the point and change what? Any help and part numbers would be appreciated. Thanks, Rinconmann

 

[Kyiv]

Hard to see anything in the pictures. You mean it's right above oil pan, correct? If it's on the passenger side, it's likely an oil level sender. It's a known common leaker. Its o-ring gasket hardens and no longer seals properly. It could also be an oil pressure sensor, which is located just slightly below (red arrow). Replacing oil level sensor requires dropping oil pan and you'd need a whole new sensor, as o-ring by itself isn't available anymore and it's a prudent thing to replace the whole thing

 

[rinconmann]

Yes I feared the pictures would not work and give enough detail. It has been a few months since I took those; I am going to take a couple of better pictures after I jack it up tonight and post those in the AM. That will provide a much better viewpoint for consideration.

 

[Kyiv]

Shine a flashlight on the area and then snap a picture

 

[gsxr]

Is that tank next to the alternator? If so, it's the coolant overflow tank from the water pump... oil leaking in this area would be coming from above; likely related to the cam solenoid area.

EDIT: Oil in this area could also be related to either the front crank seal, or timing cover edge.

 

[gerryvz]

Yes, the @gsxr is correct, confirming from you that the "oil tank" in question is on the front of the engine. If it is the coolant overflow tank from the water pump, it is connected to a nipple on the bottom of the water pump by a vertical hard plastic tube. The small tank rests on the top of the oil pan's front horizontal "shelf" where it thrusts forward under the crankshaft pulley.

In the case of my coolant overflow tank, it was inundated with dirt and debris and oil from the nearby front crankshaft seal, which had a leak for a number of years. These tanks are not needed/necessary, and anyway have gone NLA from MB. I was lucky enough to find a NOS unit.

As the @gsxr says, oil in the area could either be coming from above at the passenger side camshaft seal or cam solenoid, leaking downward, or splatter/spray/leakage from the nearby front crankshaft seal.

You can see what this tank looks like in my Top-End job photos:

Photos at the end of this post.

Photos at the beginning of this post.

 

[rinconmann]

See below pictures for a better view. Not sure what it’s called but oil cometh from it. Looks like the leak starts from the connection point of an oil line which descends to a small box shape “thing” sitting above the oil pan. Access looks......complicated for repair/replace. Seems the torsion bar needs to come out, releasing the compressor line clamps, maybe the oil pan too. Wishful perhaps but it’s real tight in there so hoping the front end disassembly of a more involved nature isn’t required. The parts leaking appear to be forward of the flywheel. Please advise and thanks in advance.

 

[gerryvz]

It is NOT an oil tank. It is a coolant overflow tank. Did you look at my links that I posted above?

Your second photo above, with the high-pressure line clamped to the front of the oilpan, is another key indicator that the front crank seal has a leak.

See photos I posted below.

Not all that much disassembly is needed to get at it. It comes out from above, not below. To get to it, you will need to remove the upper fan shroud, the serpentine belt, the smog pump pulley, and the fan clutch & pulley (and the serpentine belt). This takes some special tools that make the job go easier -- specifically a holder for the pulleys so that you can loosen the pulley bolts, and appropriate tools to remove the fan and fan clutch assembly. Generally, this is easiest/best done by removing the radiator.

The pipe that connects to the coolant overflow tank presses on to the water pump. The bottom end is held by one bolt. And there is one clamp that holds the pipe out of the way of the pulley. Again, this is ALL detailed in the posts I linked to above.

judging by the looks of the area, like me you have a front crankshaft seal leak, and that is spewing oil all over the area. You must have some oil leaks on your garage floor, and I’m sure that your bottom belly pan is an oily and dirty mess like mine was.

you are going to need to replace that crank seal. It’s an advanced DIY job, so if you are not comfortable it’s probably left to a shop to do.

ALL M119 engines leak from the front crank seal sooner or later, so if you have more than about 125K miles I’m sure yours is due for replacement.

My honest advice is that you will need to change the front crank seal. The coolant overflow tank is NOT your problem. As the @gsxr said, you can and should also check your cam seal + cam solenoid on the passenger side for leakage, but I think you'll find that the real problem is likely going to be the front crank seal throwing oil and dirt all over the front of the engine and the top of the oil pan protrusion, including on the coolant overflow tank.

My pictures in the first link I put up above, tell the entire story.

 

[rinconmann]

Hi Gerry, I had not yet read your posts until after I posted the new pictures last night. My first view back is right now. I was way off on my preliminary diagnostic "guess".

Looks like my takeaway is that I need to change the front crank seal. Can I locate that procedure within the forum searching "front crank seal" and will it have the Part numbers (Hope they are not NLA). Anything else I should RR when I do that job since I am removing the radiator and perhaps entire front end of the car looking at your pictures?

My honest advice is that you will need to change the front crank seal. The coolant overflow tank is NOT your problem. As the @gsxr said, you can and should also check your cam seal + cam solenoid on the passenger side for leakage, but I think you'll find that the real problem is likely going to be the front crank seal throwing oil and dirt all over the front of the engine and the top of the oil pan protrusion, including on the coolant overflow tank.

 

[smalldosedaily]

Hi Gerry, I had not yet read your posts until after I posted the new pictures last night. My first view back is right now. I was way off on my preliminary diagnostic guess.

Looks like my takeaway is that I need to change the front crank seal. Can I locate that procedure within the forum searching front crank seal and will it have the Part numbers (Hope they are not NLA). Anything else I should RR when I do that job since I am removing the radiator and perhaps entire front end of the car looking at your pictures?

Did you ever fix this?

Looks like I have the same issue from gsxr's description.

 

[rinconmann]

Just saw this post. No, I have yet to attack this one as the oil leak stopped so out of sight out of mind.

 

[rinconmann]

Looked today and for sure my crank seal is leaking. That's going to be a fun project as outlined by @gerryvz but doable. I'll post pictures and progress when I get into the job in the next few months.

 

[nocfn]

while you may be reluctant, just take the time to do all the things you will have access to now that you are doing the seal.

 

[gsxr]

Looked today and for sure my crank seal is leaking. That's going to be a fun project as outlined by @gerryvz but doable. I'll post pictures and progress when I get into the job in the next few months.

There's not a formal HOW-TO thread on the front crank seal, but a lot of useful information (supplemental to the FSM procedure) is in this thread:

M119 front main crank / hub seal replacement | M119 Engine

My front main crankshaft seal is leaking and needs replacement. I've looked through the service manual and Mercedes calls for installing a special locking tool to prevent the engine from rotating while undoing the main bolt and later retorquing it to the required 400Nm. I looked for info from...

www.500eboard.co