Hi all,

So, my ML500 had what I thought was a rear main seal/plate oil leak. The local M-B dealership diagnosed it and told me it was going to be about $1700 to repair. I bought original M-B parts (rear plate, seal, special M-B sealant, and a torque converter front transmission seal) and took it to a third party garage (one where their M-B specialist used to work for the stealership for 30 years thought he knew what he was doing) and had them do the job. They charged 8 hours labor by the book at $95 = $760. I picked it up last thursday morning and drove it about 100 miles and put it up on ramps last night and low and behold, the oil pan/transmission joint is soaking wet with oil again. I felt up inside the two torque converter inspection windows and it feels really good and dry up inside there, where it was wet inside there last time (could be wind pushed some oil inside there). But where the oil pan and the transmission bellhousing bolt together and the two inspection windows are located its soaked with fresh liquid oil.

Is there any thing else under there that could be leaking?? I'm at a loss now. The only other thing that I can see under there is maybe the upper oil pan is leaking where it mates with the bottom of the engine block. The lower oil pan is in the front of the vehicle and that seal to the upper oil pan seems extremely dry. With it up and ramps and with a flashlight, I can look up the rear of the engine beside the transmission on either side and see the rear of the cylinder heads where the valve covers mate and that gasket looks nice and dry too. Nothing is leaking up there and running down the engine block and collecting on the bottom of the engine. Through process of elimination I'm thinking its the oil pan. But before I undertake that massive job, I wanted to check and get other opinions and areas to look for leaks. The passenger side of the engine is easier to examine because there's no drive shaft there and it is completely dry everywhere, it looks really good. so, I'm guessing its leaking from the driver's side and from the rear. As I remove the under engine compartment cover and look around up under there its all pretty good and dry too. I'm guessing that just leaves the rear drivers side area, unfortunately its really hard to see in there because of the front differential is on that side and the front driveshaft and exhaust pipe are all crammed in that tiny area. Makes inspecting it darn near impossible.

At least with the oil pans, there are no gaskets to buy, just another tube ore two of the Locktite 5970 sealant.

I must say that I'm extremely disappointed in the mechanic didnt look around while he had the exhaust and tranny out of there doing the rear main seal, he apparently didnt examine anywhere else for other leaks or problems.

I'm also getting tired of this ML, its been nothing but trouble since I bought it. Front diff and driveshaft were bad, I rebuild the front diff and replaced the front driveshaft. Now at least those are good. And had the rear main seal replaced and transmission fluid changed at the same time. Now there's still another oil leak and the steering rack is now leaking. UGH. What a piece of junk M-B built with these ML's. Shoulda bought a japanese car, an infinity or lexus, for reliability.

But, any pointers or ideas you guys can offer would be much appreciated!!

 

i feel your pain.

does the bottom edge of the rear plate seal against the oil pan?

 

I'm not sure if it does or not. When I look up in the inspection port, it looks like it does and I can see all brand new sealant from where the rear plate was just replaced.

 

is it for sure engine oil? maybe trans fluid?

 

Its def not trans fluid. Trans fluid is red. This is light brown. So, its engine oil or possibly power steering oil. but I kind of doubt its that.

 

any updates?

 

Yes, I paid an independent third party garage with M-B certification to change the rear main seal. It wasnt cheap, I bought the parts online and paid his labor and total was about $900. The rear main seal leak is now gone. However, it was still leaking a good bit. So, I put it up on ramps and inspected very closely and discovered it was an oil pan leak at the rear corner of the oil pan on the driver's side. I also discovered the bolts werent that tight. So, I snugged them up some and the leak didnt stop completely but its so small now that it's liveable until I can sell the ML or have the time to remove the oil pan and re-seal it myself.

 

Just so I fully understand your thought process...


You diagnose an oil leak as a faulty rear main seal, purchase the parts to repair a rear main seal leak and then contract a third party to replace a rear main seal with the parts you provided (which they correctly performed) and now you are upset that you had incorrectly diagnosed the complete condition and the third party didn't do more than what you contracted them to do...


I might have more empathy if you stated to the third party that you have an oil leak and want them to identify the source and repair the condition... oh and by the way I have the parts if it turns out to be a rear main seal.

 

Seems like a smart alek comment....that is NOT how it happened at all. The local M-B dealer diagnosed the rear main seal leak. I took it to them to find out where the oil was leaking from, I paid them to diagnose it. So, once they told me the rear main seal was leaking, then I bought the parts from Mercedes parts online. Then I took it to a mechanic to change the rear main seal. Fact is, the rear main seal WAS leaking as it was wet inside the transmission bellhousing. It just so happens that the oil pan was leaking too and the dealer didnt catch that.

 

well hope it is fixed now, oil leaks are no fun

i have the ml320 that tends to have the oil cooler leaks and read on 2-3 different forums about oil leak stuff any time that issue pops up
seems a lot of oil leaks get misdiagnosed and people end up spending money on things they did not need only to find out it they need another repair

although my 08 ml320 has not had the dreaded oil cooler leak yet i am super paranoid and check the whole motor over at least every 6 weeks looking for leaks

also pressure wash it and keep it clean

think this helps some in determining where a leak is coming from, but at least on my motor it is so crammed in the engine bay that there is a lot you cannot see without taking off several parts and probably lots of labor hours

so can see where it would be easy to misdiagnose where the leaks are coming from

really sucks when you pay for a repair only to find out you needed something else, just hope your ml oil leak problem is solved now

 

I've found that my dealership often misdiagnoses problems. As for oil leaks, I had one on the ML 350 BlueTEC at 50800 miles....just out of warranty. Cost $3600 at an indy to repair....dealership estimate was around $5000.

 

Derek4484,


You are correct, it was a smart alek comment and for that I must apologize...


My past experience as a shop foreman and service manager has influenced my comments from time to time. What has amazed me is the volume of people who have one individual or company diagnose a condition and then purchase parts from a second source and have yet a third individual or company install these parts.


At this point there is no accountability by any of the parties:


1) The dealership doesn't have any skin in the game since they only looked at the condition and provided the initial diagnosis (they were correct about the rear main seal and they were paid- that ended their responsibility). The original oil leak (rear main seal) easily could have masked the secondary oil leak. Without completely cleaning the area and then operating the vehicle (like you did to verify the condition after 100 miles driving) to verify only one leak existed, they could not have reliably identified both leaks.


2) The online parts source only provided what was requested of them. They had no idea if these parts would correct the condition.


3) The third party company that installed the parts you had purchased, not from them but another source, also has no real skin in the game. They were not contracted to repair an oil leak or find any additional leaks... only to install the parts provided to them. Therefore to say, " I must say that I'm extremely disappointed in the mechanic didnt look around while he had the exhaust and tranny out of there doing the rear main seal, he apparently didnt examine anywhere else for other leaks or problems" is extremely disingenuous and disrespectful to the industrious individual that provided a service at reduced price than you were willing to pay the dealer or even pay them for the labor and parts combined.

My favorite story I relate to people is a customer which provided my shop with a carburetor rebuild kit (for those of you old enough to remember carburetors), distributor cap/rotor, spark plug wires and spark plugs and instructed me to do a "real good tune up" since I came highly recommended as the best carburetor guy in the area. I was also instructed not to do any additional work since he had already gone through several shops who "only wanted to sell him other stuff he didn't need".


So the carburetor was rebuilt, the ignition parts installed and the best tune up that could be done was completed. I also left a note that simply stated if he wanted to get rid of the lean miss condition which made the vehicle almost un-drivable, I would be happy to fix the cracked intake manifold (vacuum) leak.


In both cases (the oil leak for you and the tune up from my story) the customer had assumed the responsibility that the condition was properly diagnosed, proper parts obtained and the work completed to their satisfaction; and in both cases this does not appear to have happened.


I am sorry that you still have an oil leak and that you are disappointed with MB. I also hope that it is realized that the repair condition(s) are not the fault of the parties you contracted to assist you.

 

If you can't afford to pay dealers for major repairs on mercedes please and please park it in your garage until you have the money to fix it at a benz dealership
These cars are very delicate and require experienced technicians to work on it.

 

i am sorry but disagree with that statement, there are plenty of indie mechanics that are very good on mercedes cars

also there are plenty of very knowledgable people on these forums that are not employed by mercedes dealers

 

The next post you'll post is a piston shooting outta your oil pan ��

 

So, you've been indoctrinated. Many folks on this forum are more than qualified to do their own work and get it done successfully. Stop with the "you gotta pay to play" crap. I get enough of it on the AMG forums.

 

Not on a Mercedes Benz believe me

 

Not on a Mercedes Benz believe me

 

Nope, not gonna believe you. Check out the rest of the forums for multiple examples. A Mercedes, oops Mercedes-Benz, is still just a machine and very understandable with a little effort. I'm not going to enumerate all the work I've done on mine, but they both run fine. Neither go to dealers for work, unless it involves that top secret STAR programmer. And one of these days I'll get my hands on one of those too.

 

"You gotta pay to play" at the dealership is BS. All of these cars will eventually accumulate mileage, and will be sold at a low price to someone like me, who likes fine cars and can repair them, himself. I've owned primarily BMWs, which I buy at 80k miles, and sell at 150k, after something else catches my eye. I'm on my first MB, which has developed steering rack problems at 83k. Dealer says, "$2700," so I'm doing it myself. Got a used rack from LKQ for $385. Work in progress. If you can afford newer MBs, and can afford to go to the dealer, good for you. But don't denigrate people in different circumstances, who make different choices.