Cause of Leak at Oil Filter Housing Lid - PeachParts Mercedes-Benz Forum

bustedbenz · #1 06-09-2009, 01:04 AM

For the last 3 oil changes, I've had an oil leak out the top of my oil filter canister. I can't ever spot a drop actually running down the canister, but there's an oily film all over it where it's obviously had oil not just pouring but slowly oozing down it, fairly constantly from the looks of it.

I've replaced the gasket thing that comes with each oil filter faithfully each time I've put a new filter in, and tightened the bolts down the same way I always do (torqued them with a wrench the first few times I did it until I was comfortable, and now just do it by feel. Tight but not too tight.) I can't find any defects anywhere, no trash along the gasket, absolutely positive I haven't accidentally tightened two gaskets down in there by mistake.

Any obvious cures? I've tightened the bolts down a little extra with no effect and am not about to risk breaking the studs off or anything by really leaning on them, since it obviously should seal without that expedient, and in fact has done so on numerous occasions before.

I also, for the last few oil changes, (don't know if this is relevant or not) have been removing the filter lid and having literally a puddle of liquid oil on TOP of the filter element. It forms a pool on top of the silvery filter top (where the handle-ring thing you use to lift it in and out is). I don't remember if it's always done this or not, but I don't *think* it has. It could have though, and I didn't notice it. It's very much like oil is constantly flying up and bathing the top of the filter cap any time the engine is running, and the gasket just can't hold it all in. Is that how the filter is SUPPOSED to work or does this mean I have a dreadful I-can't-believe-your-engine-is-still-running problem like plugged passages in the filter cap stem thing or something?

Opinions? It's just a small leak but it didn't use to be a leak at all. And I can't remember to save my life if the oil has always puddled on top of the filter or not. It kinda makes sense that that whole canister would be full of pressurized oil at some point or another, but then I can also imagine somebody saying "oil's never supposed to be outside the filter cartridge"

Brian Carlton · #2 06-09-2009, 01:07 AM

Which oil filter are you using?

bustedbenz · #3 06-09-2009, 01:15 AM

I used to always use Bosch filters with cotton gin junk in them. Every now and then I'd order a Mann just to be different but never saw any different results of any kind. The last three or four filters (I just realized this - it SEEMS to correspond to the problem but I can't verify that with records to be sure) have been Hengst filters in a yellow bow, sold by Fastlane as OEM replacements for the Bosch ones they were sold out of at the time I ordered. (I bought one two orders ago to see if I noticed a difference, accepted two as stand-ins for absent Bosch stock on my most recent order, and have probably used three or four total.)

I just went down to the basement to take a good close look at one of them. The only observation I have is that the outer surface of the "upper" section - is that the bypass section? or the "main" section? - at any rate, the metal framework surrounding what I assume could be cotton gin junk or could also be better material, on these Hengst filters, seems to be MUCH more restrictive than the Bosch ones were. The Bosch ones looked perforated with holes drilled in that section. These Hengst ones seem to just have tiny little metal slits in a grid formation.

If you believe my lack of using those magic Fram filters without the cotton waste in them is the direct cause of my problem, I'm willing to try a few - but offhand, I'm having a very hard time imagining how that could be the direct result of oil spewing out where it shouldn't unless and only unless it was becoming completely plugged somehow - which ought not to happen until the oil has been in service for longer than mine has been.

F18 · #4 06-09-2009, 08:33 AM

Is there any chance that the O Ring seal for the canister lid that were supplied with the new filters is smaller/thinner than the original?
Did you save any of the old O Rings to compare?

Ether · #5 06-09-2009, 09:01 AM

When I picked up my SDL a few months ago I noticed a small oil stain on the front of the oil filter canister just below the top.

I changed the oil (Mann filter and large o ring as well) and noticed a small leak at the same location. After making sure the lid was properly torqued down I cleaned the spot and after doing this maybe 2 times the leak stopped.

Not sure what that indicates but my second oil change is coming this weekend so I am curious to see if the little leak returns.

Jeremy5848 · #6 06-09-2009, 11:28 AM

Could some small piece of debris be caught at the bottom of the oil filter cannister? That would prevent the new filter from going in as far as it should and might keep the lid from sealing completely. Ditto for something caught in the o-ring groove in the lid.

The only other thing I can think of is the two little o-rings on the pipe attached to the lid. If they don't seal correctly (old, hard, cracked) oil might flow up to the top and somehow be forced out under pressure,

Diesel911 · #7 06-09-2009, 11:30 AM

A long time ago I worked at a job where we used a lot of O-rings. What I found is that it was not unusual to find a new ont that had some defect on it.
Do a good visual inspection and stretch it a little. I has not happend often but I have stretch some a littie and them breake apart due to some interior defect.

Other problems are there is sometime pieces of rubber flashing from the molding process protruding from the O-ring or when you asseuble the item you cut off a tiny sliver of O-ring.

That being said as the other member said it is more likely that the O-rings in some filters are not exactly the right size. Companies seem to buy components from whoever happens to be cheaper at the time.

When I am in a hurry I occasionaly leave the old O-ring in on the Filter Cap. I have never had any leaks doing this. So you could pull a fatter O-ring from one of your other Oil Filter Kits and if it works just reuse it 1 time.

thayer · #8 06-28-2009, 02:22 PM

The large orings that come with the purolator (cheap) and wix(expensive) both don't fit nicely. to the point that I had to hold the oring on while I reinstalled the cannister lid. I recently bought two Mann Filters from Phil and the orings that came with that filter fit snugly and the seal is perfect.

Oh and by they way...make sure that the lid is facing the correct direction. I installed it backwards once while I was in a hurry. Yeah, no seal if its on backwards in my case.

Brian Carlton · #9 06-28-2009, 03:51 PM

Quote:

Originally Posted by bustedbenz

For the last 3 oil changes, I've had an oil leak out the top of my oil filter canister. I can't ever spot a drop actually running down the canister, but there's an oily film all over it where it's obviously had oil not just pouring but slowly oozing down it, fairly constantly from the looks of it.

Next oil change, get yourself a hand grinding stone, small size, medium grit.

Dry the top of the housing thoroughly and use the grinding stone to carefully work the surface seeking high spots. Don't go crazy.........you're looking for one, maybe two very shiny spots that appear when you pass the stone over the surface. You may also feel some drag on the stone at these points.

It only takes a very slight deformation of the aluminum to cause a leak past the o-ring.

The other possibility is some accumulated debris in the cover. Take some 0 steel wool and polish the inside of the cover where the o-ring sits. Naturally, it's got to be perfectly clean in this counterbore before installing the o-ring.

pawoSD · #10 06-28-2009, 04:01 PM

On my most recent oil change I used one of the Napa Gold series filters without the cotton waste section for the bypass, the whole thing is pleated paper. Anyways, it came with a cover o-ring that was a tad bigger than the lid and did not "stick" to the lid, I had to hold it on and lower it in place. No leaks though, but kinda annoying.

Diesel911 · #11 06-28-2009, 09:17 PM

Quote:

Originally Posted by pawoSD

On my most recent oil change I used one of the Napa Gold series filters without the cotton waste section for the bypass, the whole thing is pleated paper. Anyways, it came with a cover o-ring that was a tad bigger than the lid and did not "stick" to the lid, I had to hold it on and lower it in place. No leaks though, but kinda annoying.

Concerning the Full Flow section of the Oil Filters for the 617 Engines the Purolator at 35 Nominal Microns (from their Email to me) and the WIX with the all paper media passes the largest particles through the filter; 32 Microns. Compare this to the Data the DeliveryValve has accumulated in post #32 in the Thread Below.

NAPA Gold Filters

WIX filter site that in most cases shows the Micron Rating of their filters.
http://www.wixfilters.com/filterlookup/index.asp

For the other Mercedes Diesels the WIX filters are OK but you can look the Micron Rating up yourself.

tangofox007 · #12 06-28-2009, 09:53 PM

Quote:

Originally Posted by bustedbenz

Any obvious cures?

How many vacuum lines are clamped under the lid?

pawoSD · #13 06-29-2009, 08:04 AM

Quote:

Originally Posted by Diesel911

Concerning the Full Flow section of the Oil Filters for the 617 Engines the Purolator at 35 Nominal Microns (from their Email to me) and the WIX with the all paper media passes the largest particles through the filter; 32 Microns. Compare this to the Data the DeliveryValve has accumulated in post #32 in the Thread Below.

NAPA Gold Filters

WIX filter site that in most cases shows the Micron Rating of their filters.
http://www.wixfilters.com/filterlookup/index.asp

For the other Mercedes Diesels the WIX filters are OK but you can look the Micron Rating up yourself.

Great. Looks like I am chopping 1k off my oil change interval.

I'm going with Baldwin next time, or back to the Turkish Frams.