5 years ago oil the oil filter cap after driving 9 hours and seconds from destination leaked a huge amount of oil out of the screw on cap/filter.
Cleaned it up, fresh filter o rings, and oil.
Now 5 years later and multiple oil changes later everyone preformed myself. The oil leak is back. Currently trying the 2nd new cap and filter and
after minute it starts seeping out at a random location localized spot of cap at housing and cap lip. Several R&R just leak moves to around the lip.
Thoughts on this random leak? Replacing housing, possible blocking within cooler???, open to any ideas.

 

Orings should be replaced at every oil change. Make sure the cap oring is in the correct groove. Make sure the oil filter housing is not cracked at the lip (not typical)

 

O rings are always fresh, I have sourced 2 new caps and filters. the leak shows up after minute or two idling.

 

There is a gasket between housing and block as well.

 

I'd also be curious to something pressure related/internal to the entire assembly myself. I had to replace my entire oil filter housing/oil cooler assembly but for a different leak. The famous oil cooler gasket and eventually oil filter housing gasket which were only remedied by a new assembly. (Also oil in coolant).

I never got true proper info on the failure other than "internal check valve failure, oil & coolant mix & leak externally". This was from a Benz indy shop owner who is a master tech and former dealership shop foreman. I wonder if your issue is pressure related?

The assembly has had at least 1 if not 2 part number revisions. I understand this is sometimes due to Benz sourcing a different company to manufacture a part and not always a mechanical revision on said part, but again I need more info on that myself. Just a consideration.

 

Probably telling you things you already know but just to be sure - the grove for the large O ring is 1/2 inch from where it seals. I've put mine on incorrectly once and oil everywhere.

Check the filler assembly is straight on the neck where the filter attaches- they can bend out of shape. Also, which filter set are you using? I've always used MAN and never had a problem but others might have a different spec on the O ring?

 

You can put the o-ring too far back and too far forward on the cap.

It has a specific receiver groove but it also *could* theorhetically seat behind that groove too. You're seating the filter all the way so the line disappears right?

 

What brand filter? If it's a good brand, are you using the o-rings that come with it or your own o-rings? If they're rubber o-rings, the oil/vapor will deteriorate or harden the o-ring.

 

Oh yeah, it’s really easy to think the O-ring rides on the lip of the oil filter housing vice the groove.

That would create one monstrous leak.

 

That's interesting to think about certain manufacturers of filters coming with insufficient o rings. I've also only used Mann and never an issue.

Literally every other seal, gasket, or o ring that wasn't Genuine (besides 1 Elring trans pan gasket) has given me instant issue like your situation. Especially an o ring w/ a Bosch crank position sensor. Literally twice the size of the Genuine one I sourced locally and the sensor wouldn't even fully seat.

 

Here’s a photo of the correct O-ring slot from a related thread

https://www.pelicanparts.com/techart...Oil_Change.htm

OP can you confirm that the big O-ring is seated correctly?

 

Since purchase at 102k and now showing 265K I have done all the changes.never an issue. Hell to be honest I may have only changed the rings twice.
I have used to different caps several sets of rings and as I have stated it is a 1/4 inch wide slow stream. If I change caps and or rings it just moves around somewhere else
just under lip.
W
Has any one experienced blockage in the oil cooler?

 

Dude WHAT?! I've never heard of this lmao... I replace the DIPSTICK o-ring after every oil change because it gets noticeably less useful after 10k miles.

Oil cooler has a ball check valve or something in it yeah but thats not why it's leaking, it's not meant to be user serviceable and I strongly recommend changing the entire oil cooler. The URO part suffices 99% of the time.

I think you have a cracked oil filter housing.. aluminum has a finite lifespan for stress.

 

"Since purchase at 102k and now showing 265K I have done all the changes.never an issue. Hell to be honest I may have only changed the rings twice."

In a 1063K miles you've only changed the o-rigns twice????

If you had a blockage somewhere, causing built-up pressure, you'd have other issues. But it sure is easy to check - DO you have pressure?

How closely have you inspected the housing?

Are you tightening the cap all the way down?

 

Thanks, I am thinking it is INTERNAL. This issue surfaced 5 years ago, after driving 9 hours to a friends, hung around went out to store on way back about 100 ft from his house saw smoke. Engine covered in oil, lost 3 quarts. cleaned replaced filter. It has been fine since 1/2020. Now can not stop it.
Thanks

 

Given all the experiences here, have you checked your oil filler cap? Mine broke the handle and I expected that even so, it would still work properly. Wrong! The plastic handle grabs the filler neck and generates pressure for the seal. Check that as you noted you had oil all over the engine. Mine leaked quite a bit, enough to hit the exhaust manifold and created plenty of smoke.