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Cls55 102k miles. After installing a new trans mount two days ago I noticed a small amount of oil seepage mixed with dirt right where trans meets bell housing. Also noticed a small amount by the two rectangular black plastic plugs on bottom of trans. Wiped off oil after install of trans mount, checked today, still tiny amount of seapage. No leaks on trans pan or the electrical connector. Oil is a light brown color, does not look like trans fluid. I did an oil change about 150miles ago and put in 8.6 quarts of liqui moly plus 300ml of Ceratec. I know I overfilled by a bit - could that be the reason for the leak? I’ve also heard the rear main seal or torque converter could be the problem but since it doesn’t look like trans fluid is being leaked I’m not sure those are the culprits.
Cls55 102k miles. After installing a new trans mount two days ago I noticed a small amount of oil seepage mixed with dirt right where trans meets bell housing. Also noticed a small amount by the two rectangular black plastic plugs on bottom of trans. Wiped off oil after install of trans mount, checked today, still tiny amount of seapage. No leaks on trans pan or the electrical connector. Oil is a light brown color, does not look like trans fluid. I did an oil change about 150miles ago and put in 8.6 quarts of liqui moly plus 300ml of Ceratec. I know I overfilled by a bit - could that be the reason for the leak? I’ve also heard the rear main seal or torque converter could be the problem but since it doesn’t look like trans fluid is being leaked I’m not sure those are the culprits.
most likely rear main engine seal. Could also be transmission front pump seal.
Relatively common across MB engines. Smell the leaking/weeping fluid. If it smells like engine oil, it came from a spill (overfilling) or a leak. The leak is either internal or external. If the leak is presenting as coming from inside the bell housing, this to me is an internal leak. The only leak path for engine oil inside the bell housing is the rear main crankshaft seal. There is no engine oil in the torque convertor or transmission.
Relatively common across MB engines. Smell the leaking/weeping fluid. If it smells like engine oil, it came from a spill (overfilling) or a leak. The leak is either internal or external. If the leak is presenting as coming from inside the bell housing, this to me is an internal leak. The only leak path for engine oil inside the bell housing is the rear main crankshaft seal. There is no engine oil in the torque convertor or transmission.
It definitely looks like engine oil, hard to smell it since it’s very fresh. Oil was mostly around the two black plastic square plugs and on the seam where trans and bell housing meet. I’ll monitor the area as more miles are put on and oil is burned off, hoping it’s just the result of overfill. Thank you for the input.
Rear main seal leak is common. Of the 5 Mercedes I owned from this time period only one have not develop a leak. I would not do anything unless it got worse. On my cars it never gotten any worse than a tiny amount of oil around the black plugs.
It definitely looks like engine oil, hard to smell it since it’s very fresh. Oil was mostly around the two black plastic square plugs and on the seam where trans and bell housing meet. I’ll monitor the area as more miles are put on and oil is burned off, hoping it’s just the result of overfill. Thank you for the input.
Wipe some oil off the bell housing with your finger and smell it.
Rear main seal leak is common. Of the 5 Mercedes I owned from this time period only one have not develop a leak. I would not do anything unless it got worse. On my cars it never gotten any worse than a tiny amount of oil around the black plugs.
Ive also heard it's common. Ill monitor it, as long as it doesn't lead to bigger problem(s) I'll hold off on that repair
I think the description same as happened in my 2013 ML350 35k miles. I have noticed also the oil stick is little bit above max. I think it must be result of over filling. I bring to shop and as I expect that told me rear main seal and they want to send quote. It not dripping to bottom panel. The shop like this because they make fortune from it. I remember one post fixing transfer case and the picture of leaking like this and he didn't get repaired and ok for last 6 years. I think this what mentioned as sweating not leaking as long you didn't loose oil fast it can be ignored or pay 9 hour x $130 plus part to fix it.
Thinking of this maybe it can be used as tactic by shop is to over fill engine oil and when customer came back than it will be rear main seal sealing. Somebody need to test it try to overfill and see it will get oil close to that two rectangular port.
The shop quote me for $1484.58 +tax Rear Main Seal
Parts Qty
Crankshaft Seal with Flange 1.0
Gasket Maker EL-Liq 74 50ML 1.0
One of posting in forum claimed he had using 6 mercedes and only one of them didn't have oil sweat like this
It makes sense to me if the mechanic shop uses this tactic for profit. Do you happen to know the part number for those two rectangular plastic ports? I cannot find it anywhere
Cls55 102k miles. After installing a new trans mount two days ago I noticed a small amount of oil seepage mixed with dirt right where trans meets bell housing. Also noticed a small amount by the two rectangular black plastic plugs on bottom of trans. Wiped off oil after install of trans mount, checked today, still tiny amount of seapage. No leaks on trans pan or the electrical connector. Oil is a light brown color, does not look like trans fluid. I did an oil change about 150miles ago and put in 8.6 quarts of liqui moly plus 300ml of Ceratec. I know I overfilled by a bit - could that be the reason for the leak? I’ve also heard the rear main seal or torque converter could be the problem but since it doesn’t look like trans fluid is being leaked I’m not sure those are the culprits.
All supercharged AMG engines eventually weep from the rear main seal, and all supercharged AMG engines use oil every month. Honestly, it's normal.
Yes I remember had BMW 530 2007 few years ago and it is Turbo engine so it leak oil everywhere and BMW estimate $10k to fix and in fact the car is value less than that. Turbo engine mean high pressure and high temperature so gasket will not live long. That my first lesson no more turbo engine. Now I had W212 E350 no Turbo just regular V6 but it had 4matic. So front drive shaft broke close to differential then 2 year after front propeller replaced now u joint in transfer case for front propeller broke. Lesson two no more 4matic if you want to safe money maintained car above 100k miles. Not easy to repair transfer case because it part of transmission so MB will only replace whole transmission including transfer case for $8k.
All supercharged AMG engines eventually weep from the rear main seal, and all supercharged AMG engines use oil every month. Honestly, it's normal.
Glad to know the rear main seal isn’t an imminent life or death type of thing. Will be fixed at some point but this gives me more reason for other upgrades
Glad to know the rear main seal isn’t an imminent life or death type of thing. Will be fixed at some point but this gives me more reason for other upgrades
It may not be an imminent threat, but it certainly will end up being a mess unless it isn’t tended to! I, like you, experienced “a little seepage” and then went on a road trip (350mi) only to experience repeated Oil refills and a bunch of smoke from that oil ending up on my exhaust pipe! There’s a weep hole at the top of the bell housing too that disperses that oil to the back side of the engine that eventually drips from, in my case, the 1” Heater Hose (and everywhere else!) I used to fab up a catch can running down passenger side behind the headlight. I spent an inordinate amount of time and effort cleaning my exhaust pipe when I removed it do my Rear Main Seal ( Trans Valve Body Clean, Drive Shaft Rubber Discs, Subframe & K-Mac Control Arm Bushings, Tranny/Engine Mounts, P/S Bushings, Rear Diff LSD and gear change to 3.06, Ultimate Toe Arms, AirSprings, Shocks, Hubs, Rotors, Pads) as the smell from oil every time I ran the engine got worse and worse! Here are some pics of my efforts!
I bought a Tranny Jack lifter from Harbor Freight for $99 that has saved my bacon so many times I can’t even tell you! I used it to drop my tranny after using several layers of particle board/plywood cut in 12” squares to situate under each jack stand in order to get the car high enough to drop the tranny. In my garage, there’s a raised level of about 4” going across which serves as a perfect place to set my Ramps. I actually use a couple of 2x6’s cut to same length (about 2 feet) to set those ramps even closer to the garage door otherwise the nose of the car will be so far forward that I can’t get a jack in front otherwise that raised section would be in the way. This method just barely allows me to get the car up high enough, but after raising it on the ramps, I then raise the rear, set on stands and then raise the front to set on stands. The ramps are long enough so as to impede the ability to set stands up at the specific spots up front whilst the tires are applying pressure to the Ramps, so I’ll use a piece of 4x4 on top of the jack to allow me to raise the front high enough to clear the ramps and set the stands. Then do it all over again until I get just the right height. I forget exactly how high but a quick ball park measurement of the height of the tranny + the height of the lowest setting of the Tranny Jack = about how high you need to be!
As to removing the the Tranny, well you must consider which direction the Engine will move after the Tranny is disconnected. Logically it moves forward, but I’ve read accounts of it moving backward which could seriously damage the brake lines etc, so prepare beforehand by setting up blocks of wood bracing the engine both ways. If you have an engine hoist, your golden, although it is NOT required. After discoing the 02 sensors as well as the ground connection driver side, draining tranny fluid, flushing fluid from the tranny lines, draining the Torque Converter and disconnecting it from the flywheel, removing the exhaust because otherwise you can’t access the removal of the Drive Shaft (perhaps you can, but being as I was replacing the whole rear end, that’s what I did), then comes time to disco the tranny from the engine. If your planning on cleaning the valve body, now is the time to remove it and then reinstall the pan to support the tranny on the Tranny Jack while it is off the car. Set up the Tranny Jack underneath and disconnect the entire support holding the rear tranny mount. Then after loosening the lower bolts between 4&8 O’Clock, position yourself towards the rear of the tranny and look frontwards above on both sides (preferably with a Headlamp on!!) you’ll see those bolts from 9 to 3 O’Clock that are removable only from that position because you otherwise won’t see those bolts! Get your set of extensions ready and go to town! There are two alignment pins (more like 6mm tubes) on the tranny extending into the engine that will keep it from being free, so it may need some encouragement! All in, it took me about 4-5 hours just to remove. I’m a year into the rear rebuild however!
05-02-2021, 10:39 PM
