After quite a few hours of “detective work” over several months, I have narrowed an oil leak down to either one or two places. The attached photos show oil around the base of the filter housing and also the joint between the oil cooler and filter housing. NOTE: There is NO oil leaking from the filter cap.

I know the oil cooler is fairly easy to take off, but the filter housing is held in place by a threaded insert with a HUGE nut (maybe 48mm). I couldn't find a thread that ever mentioned the housing leaking or any tips on removal/repair.

Any opinions regarding the probability of one leak location over the other?

Thanks, Robert
IMG_0009.JPG Oil_leak.JPG IMG_0014.JPG

 

I can's see anything in your pic, but worth looking at is power-steering fluid as the reservoir is right there.

 

Sorry the pix aren't any better. I've checked the PS pump. It's definitely engine oil.

 

If you haven't already I would spray some degreaser on it and clean it off and see if it comes back after a little driving to be sure it's leaking from there before you go through taking it all a part to fix.

 

I actually did that on more than one occasion, 'cause I just couldn't believe it would be leaking from that area. But alas, it appears to be from one or both of the areas mentioned. Another triumph in German engineering!

Of course, it doesn't quite compare with trying to change the valve cover gaskets on my daughters 2000 4Runner. You have to practically dismantle the entire top of the engine to get to the driver's side.

 

Did you check and replace the o rings on the filter cap? Had one fail on me where the ring itself was not the correct size and did not seal well...oil and a new belt came after the tow truck took the car to the dealer.

 

Checked and double checked. I've put new o-rings in twice as well....grrrrrrr

 

The valve covers in these are notorious for leaks. Just had my 06 roadster leaked fixed, cleaned & resealed, replaced gaskets & torqued to specs.

 

I'm bumping this, hoping someone can help. Though the I greatly appreciate people taking the time to respond, I didn't get any useful answers. To be clear, the leak is coming from one of two places (filter body or oil cooler). I know all about the valve covers, breather covers, oil filter o-rings, torque specs etc.

Has anyone replaced the gaskets at either of these two locations? (See diagram, parts 17, 23, 35)

Thanks again, Robert

OIL FILTER AND OIL COOLER

 

Where is this big nut anyway, I have looked and did not see it. How that filter housing is held on remains a mystery to me.

When it comes to oil leaks I have found that you have to keep looking at it developing all the time, say after every drive. Looking at it after two weeks is a waste of time, by that time the oil has moved or the whole area is covered in oil.

 

Remember that there are only 3,000 SRTs in the world, most of us don't have one - and I've gotta say, after 4 years on this forum, this is a new one!

 

I have not replaced these, but I see what you're talking about. It looks like you'll need all three of those "seal rings" just to be sure you're replacing the right one. I wonder what size that "Internal nut" down in there is, that is holding down the filter body. You'd be the first that I know of to do this, let us know. Good luck w/ it.

 

That's pretty much the way I'm leaning. I've been trying to track down this leak for months. I've cleaned everything multiple times and checked the bay for oil after every drive. To my best "guess" I think the leak is in one of the two places mentioned.

I'm going to try and determine the size of the "nut", as I can't find any TSB referencing the removal/reinstallation of the filter body, nor has anyone in various forums been able to address this issue. (sigh) I'm a little too old to be forging into virgin territory!

I'll post my results.

Thanks to all,
Robert

 

There is a PDF on the MB forum for this, but it does not mention the nut size ....
http://www.benzworld.org/forums/atta...lter-housing-1

 

i have removed the oil filter housing on our car when I swapped the heads. there is a rubber gasket underneath the oil filter housing and I suspect that is your leak. I will check on our spare motor for the socket size for you and get you a price on the seal later tonight. not a difficult job to swap out, your in luck

 

Many thanks to my Alabama Yankee friend and Rob @ NeedsWings. Good information from both of you. Rob, I've got the part numbers for the seals. It's trying to figure out that damn socket size! Rough guess is 48mm. Let me know what you find out...

Thanks again!

 

Hit up your truck mechanic buddies for a 1 7/8 " socket and see if that works .......

 

im sorry I have not yet found the right socket here to verify, waiting for Tom to bring by his giant socket set so we can figure this out for ya

 

a couple of docs attached (so I can use them when I'm away from my PC)
- mainly for torque values which the other one didnt have.

 

Follow up:

I managed to get the right size socket (46mm) to remove the bolt from the oil filter housing. I first removed the secondary air tubing and the top radiator hose. Next I removed the oil cooler hoses and the the four bolts holding the oil cooler to the oil filter housing. Finally, the oil filter housing itself. Pretty straight forward.

The o-rings between the oil cooler and housing and the ring between the housing and time cover were very hard and brittle. Not too surprising in a car of this age, but these rings were TOO hard and brittle. I suspect (or hope) they may have reformulated the material a bit. The new rings came as kit (all three).

While inspecting the oil filter housing, I discovered what appeared to be a hairline fracture in the oil filter housing case. I didn't want to take a chance so I purchased a new one. I got the part in yesterday and installed it onto the timing case. Next, I tried to install the oil cooler to the oil filter housing. For the life of me I couldn't get any of the for bolts to thread into the oil filter housing. I took the housing back off, and holy-schnikees there were NO threads tapped into the body of the oil filter housing. WTF? Fortunately, I had a small tap & die set and cut the needed threads. Geesh, does MB just want me go crazy(er)?

Installation was the reverse. Though I probably could have installed the oil cooler to the filter housing first. The only issue would have been reconnecting the coolant hoses to the oil cooler. It's a very tight space and it helps to have the oil cooler free to wiggle the hoses into place and clamp them off.

Got it all back together now and so far so good. Still have to replace the shifter linkage bushing before I can do a decent test under load. But that's another thread...