Mercedes OM642 V6 Diesel C, E, S, R, ML, GL Engine Mount Replace and Reinforce

How I replaced the W204 C320CDI LHS engine mount and reinforced both sides with high strength polyurethane construction flexible sealant.
I've since replaced the RHS and the process was the same other than I had to remove the CAT to create enough space.
The polyurethane transmits additional vibration so don't perform this modification if you wish to retain the original feeling of standard engine mounts.

[@michaelashton3006]

One of the best how-to-do it I've seen on here. Hate those US guys that blather on about crap and then try to do the job one handed while occasionally getting the subject in shot! Good Job sir

[@ScottElliott152]

Thanks Michael.

[@richardedwards7780]

Thanks Scott! Watched 3 or 4 times and just did. No bother at all. I heard others say they had to remove exhaust etc... I had trouble getting that side in but some vaseline on it made it slide between the engine and the heat shield. Thanks again! A really useful video. Couldn't have done it without this help.

[@ScottElliott152]

Well done Richard.

[@myyasser1449]

very nice of you to share this video, a great info for so many around the world. well done.

[@vazza7504]

Just watched this video you put up, brilliant video buddy. Neighbours 2011 e350 v6 diesel is showing same symptoms. Will show him this and perform same test as you show. Thanks, vinny. :-) liverpool england.

[@jesseparris6507]

Here's my write up on it: I have a U.S. spec'd 2011 W212 OM642 Bluetec sedan. (My car is the US model so the steering wheel is on the correct side, lol.) This write-up is for U.S. spec models with the steering wheel on the right facing the car. DPF/Catalytic converter are on the passenger side I'm putting this here because there is a huge misconception about the U.S. spec W212 om642 engine mount removal process. I did NOT have to remove the DPF/Catalytic converter on the passenger side or loosen the sub-frame. I could not find one single video anywhere showing how to remove U.S. spec W212 diesel engine mounts without removing the DPF/CAT converter or dropping the sub-frame. ------------------------------------------------------------------------ 1. Before I raised/jacked up the car: a. Pretty much goes without saying that the left side motor mount is different from the right side motor mount; two different part numbers, also Bluetec diesel engine mounts are different than the gasoline engine mounts. b. Notch and pin placement: There is a notch on the engine mount arm that lines up with the engine mount. The engine mounts have a pin that fits up into that arm notch that orientates the correct placement. (I also used the rubber seat for placement reference as well.) c. I removed the plastic top cover d. Next was to remove the top bolt on the left and right side engine mounts. There are several KZbin videos on how to do this with special tools. I was able to get by using swivel extensions with a socket. 2. Raise/jack up the car: a. Removing the front tires are an option but I didn't need to. You will want to loosen the lug nuts now if you take the tires off. b. If you DIY in your driveway or garage, I cannot emphasize enough to use jack stands along with your floor jack. You cannot use too many floor jacks or jack stands. Make sure rear wheels are chocked and parking brake is on. 3. Once underneath: a. I removed the front engine cover over the radiator, sway bar and power steering rack. Then the back plastic engine cover. b. Next, I removed the bottom two bolts from each old motor mount. 4. There is a precise process to raising the engine: a. Place whatever jack you are using underneath the motor. I centered a bottle jack with a short piece of 2x4 wood across the flat part of the oil pan up closer to the front so as not to dent anything. b. My technique was to incrementally raise the engine about an eight to a quarter inch each time then checking the looseness of the old engine mount. 5. I replaced the driver's side motor mount first. (This would be the opposite side to the U.S. spec DPF/Catalytic converter.) I would jack up a little, then try to move the old mount out. When I could finally get the driver's side motor mount out of it's placement, I dropped it out in the space going toward the back of the car. I went back and forth real slowly raising the motor a little until the old mount dropped out. I had to jack the motor up some more to install the new motor mount because it's higher. When I placed the new mount in, I visually checked to see that the top of the mount matched the notch in the engine-side arm. I loosely put the two bottom bolts in the new mount using red thread locker. 6. To replace the passenger side motor mount: I had to raise the engine up more until I finally could pull the old engine mount out of it's placement and bring it FORWARD toward the radiator.(again, U.S. spec W212- now on the same side as the DPF/CAT.) ) The space is there but the sway bar and the upper power steering rack (fluid re-circulation line) bolt will be in the way. a. I undid the sway bar and let it drop. b. I undid the steering rack (fluid re-circulation line) upper bolt. (have a bowl to catch the fluid and there are two copper washers.) c. I GENTLY pushed the power steering fluid line up just a little until it was just out of the way enough for the old mount to drop through and out. (the old mount pushes the sway bar down as it comes out but I did have to pull it way down.) I did have to go back and forth jacking the motor up a little each time until it dropped through. I TOOK MY TIME. I had the new engine mount right next to me and immediately pushed it back through the space into it's placement, then loosely secured it with the two bottom bolts. (I used red thread locker.) d. I screwed the steering wheel rack bolt back in making sure both inner and outer copper washers were there; then reinstalled the sway bar. (I used red thread locker on the sway bar.) 7. To secure the motor mount top bolts, I did one side at a time. My driver's side engine arm was a little lower and closer to the new engine mount than the passenger's so I started there. I used a steel punch in the upper bolt hole initially as a guide to make sure the new engine mount pin slid into the arm notch as I incrementally let the engine down SLOWLY just a little each time (an eigtht to a quarter inch) with a check for fitment. If you have a second person to watch it helps. So the idea is to drop the engine down VERY SLOWLY until the new engine mount pin is just catching in the arm notch then remove the guide (steel punch) because it's still loose. I pulled the punch out and dropped in the top bolt loosely tightening it all the way down. Then the other side. I slowly let engine completely down, then removed the bottle jack. I finger-tightened the left and right side top bolts all the way down snug. (I used red thread locker.) 8. I tighened the bottom four bolts on the new mounts. 9. I installed the transmission mount. Then I put the front and rear plastic shields back on There are a lot of KZbin videos on how the DIY W212 trans mount. 10. With the car down on the ground, I tightened the top engine mount bolts. 11. I added the same amount of power steering fluid back in when I was done and worked the steering wheel back and forth to get rid of the cavitation noise in the rack. I think this was everything. It's what worked for me.

[@ScottElliott152]

Jesse thanks for the detailed write up. It should be helpful to those with the W212 OM642.

[@jetttskiman]

I've been searching for hours for a US version. I've got a 2013 bluetec and was wondering if its was going to be the same or similar to Scotts video here. In your #9 step you said you installed the transmission mount. Did you just replace it after the engine mounts or remove it earlier? I didn't see the removal step in the list. Thanks a lot for posting. I just ordered a set for mine.

[@johnvieira4185]

Excellent. I need to test mine as worn mounts (2011 W251) can affect transmission shifts too. Not sure how much your poly glue will help considering the engine weight and the fact mounts wear out and collapse down so the poly won't add support. I saw your transmission service video and will be doing mine when the weather warms up here using your compressed air method. Just doing fuel filter right now. Very though and clear description and good videos. I hope you do more.

[@ScottElliott152]

Thanks John. The reinforcing works well especially for the LHS. When you accelerate the engine twists trying to pull the centre out of the LHS mount. You can see how mine had failed ... the centre was ripped out of the housing. Also that poly material has amazing adhesive properties and is very strong in tension. As long as the mount is clean that product sticks so well you'd be amazed. I'll keep making videos as the jobs come up.

[@rogerburman4211]

Brilliant. About to do ours! Thanks for sharing. Very informative.

[@ScottElliott152]

Thanks Roger.

[@afzamoto5325]

Great video. Thank you so much for sharing.

[@ScottElliott152]

Thanks for the compliment.

[@olanal5]

Hi Scott, Thanks for sharing this, I was wondering when you were jacking the motor up to replace the engine mount were you just jacking on the pressed steel oil pan with the timber giving you enough surface area not to do any damage. It was a bit hard to see on the video. You comment would be greatly appreciated. Regards Alan

[@ScottElliott152]

Thanks Olanal. Yes I jacked on the steel oil pan with a piece of wood for protection and to spread the load. Regards, Scott

[@colinaglae2605]

Another nice video. Thanx for sharing.

[@ScottElliott152]

Happy to help.

[@macardabirturk9380]

Thank you sir great video

[@ScottElliott152]

Thanks.

[@DrewFixIt]

Hi Scott, as usual great video! I’m thinking of changing the mounts in my ML (W164), have you done these in your daughters ML and if so, was the procedure the same? Thanks Drew

[@ScottElliott152]

Thanks Drew. No haven't done them on the ML but the process would be similar. She sold the ML last year and now drives a Toyota!

[@jesseparris6507]

I'm confused. I see where you removed the air box on the driver's side (assuming your steering wheel is on the right side facing the car like in the U.S.) but I don't see where you went to the opposite side to do the other motor mount next to the catalytic converter. I've got the driver side motor mount out and replaced easily but I can't find an opening large enough to drop the opposite side out. I have the engine jacked up as far as it will go. Looks like the sub frame has to be dropped just an inch or two as well. Any ideas?

[@ScottElliott152]

Jesse I'm in Australia and we're RH drive so my steering wheel is on the other side. The mount I did in the video was the my passengers side or the Driver's side in your case. I actually replaced the other side last month ... that's the passengers side in your case. You have to remove the CAT and jack the engine to make the room to get it out.

[@jesseparris6507]

@@ScottElliott152 I didn’t have to drop the cat: I raised the motor, went in the other direction and dropped the sway bar and unbolted the far (would be my passenger side) power steering fluid delivery bolt(not the whole unit) and it fell right out. Took me about five hours total on my driveway which included the transmission mount as well . I got quoted $650 for this job!

[@ScottElliott152]

@@jesseparris6507 Yes I'm sure there are other methods ... it's about creating the space. My car has the 3.0 litre V6 turbo diesel. What engine do you have? Creating the space to get the mount out varies a bit depending on the engine you have.

[@xxsekoxx]

I need help. I need to replace my motor & tranny mounts. Also all plugs and pump on back of motor. Mechanic is trying to charge 3,000. Seems like a CRAZY amount. What should i do. W204 C300 4matic.

[@ScottElliott152]

Sorry for the late reply but this comment was send to spam. You'll have to do the research and decide if it's a project you can DIY. www.benzworld.org is a good source of information.

[@rahulsoni6652]

Thanks so much for the info, but I need to know how do I get the right side engine mount out , drop the exhaust? Or is there some other way?

[@ScottElliott152]

The RHS is difficult because so many components need removing to get access. kzbin.info/www/bejne/eKGXoZuLrdaJqqs&pbjreload=10 This guy made a special tool and got it out with less hassle. kzbin.info/www/bejne/bIOtaJSjhdhqitU&pbjreload=10

[@MrNorden1]

Great video. I have s212 14 350 cdi 4 matic. Is the same procedure?

[@ScottElliott152]

Yes understand it is. Access my be different because of the transfer case. www.benzworld.org has a lot of information. Someone will have done it in a 4matic.

[@ericwoolford6972]

Hey Scott, love the vids! Have you ever had an issue with the EIS? I have an issue when inserting the key there is no lights and if I remove Fuse 27 then reinsert intermittently the dash lights will power up but wont start, (strange). I ran a diagnostic using Xentry which returns a 118100 Relay N10/1kN error, Front SAM control unit with fuse and relay module switches off too late. I had the ESL replaced and coded to the EIS and keys but this did no change anything so wondering if you have any experience or suggestions in this area? Also do you have a copy of the DAS developer program where you were able to program the transmission torque which I viewed previously. Any help would be great. Thanks in advance.

[@ScottElliott152]

Thanks Eric. I've had no problems with the EIS and therefore no experience with it. Using DAS 10-2008 I was able to remove the torque limit as shown in the video. I wasn't able to actually set a torque figure. I downloaded my copies of DAS from www.mhhauto.com DAS Developer isn't a separate program ... you unlock Developer mode within DAS/XENTRY.

[@ericwoolford6972]

@@ScottElliott152 Thanks Scott greatly appreciated and will give it a go. Should I get to a fix for my issues I will share it with you as I have the same W204 as you. Keep up the good work, Cheers

[@fabiozerique2416]

Was the passenger side mount basically the same process for removal?

[@ScottElliott152]

The RHS is difficult because so many components need removing to get access. kzbin.info/www/bejne/eKGXoZuLrdaJqqs&pbjreload=10 This guy made a special tool and got it out with less hassle. kzbin.info/www/bejne/bIOtaJSjhdhqitU&pbjreload=10

[@Bedarijaena]

Hi Scott, I have more or less completely worn engine mounts, they were on the car for 11 years. I was wondering, what if I keep worn engine mounts and apply lots of polyurethane on them. What do you think, would this be a very bad idea or worth trying? Thank you.

[@ScottElliott152]

Beda the engine mounts on the Mercedes and many cars are both rubber and hydraulic. If the mounts have collapsed you'll need to replace them but you can reinforce them like I did to give a longer life. Scott

[@mikewebb3574]

Hi Scott, I’m a Mercedes-Benz technician and have been looking for fix for these mounts. Can you give an update on how they have performed over time?

[@ScottElliott152]

Mike they're still going very well. It was a good modification. The LHS in particular needs strengthening as the motor twists clockwise viewed from the drivers seat. Scott

[@mattcarlson9720]

Are these the same mounts as the 2011 c300 4matic sport

[@ScottElliott152]

Probably ... use this online parts finder. partsouq.com/

[@rcrc5260]

I have the c300 2010, does bad engin mount couse the engin to shake ?

[@ScottElliott152]

Mine wasn't shaking during normal driving. But it would lift and thump back down again under brisk acceleration. Do the test as shown in the first part of the video. Hold your foot hard on the brake, select drive and gradually push your foot on throttle and see if the engine jumps up. Be careful and make sure no one is in front of the car. Scott

[@rcrc5260]

@@ScottElliott152 I did the same test, engin is fixed, no shaking when doing the test, however, I feel the vibration and on full stop or when the car is on Drive, also when the car is on park I can see some vibration from the engin

[@ScottElliott152]

Check the rubber block mount at the rear of the transmission. The transmission and engine are one unit once bolted together. That unit is supported by three points ... the two engine mounts at the front and the single rubber mount at the rear of the transmission.

[@apassionfortangling3671]

Hi Scott, was this making any clonking over bumps and potholes? 🤔

[@ScottElliott152]

Lol ... missing link younger brother! No I didn't notice any thumping over potholes ... it was always when accelerating. The LH mount had completely failed so the motor was flopping around. My repair has been good as I've had no further issues despite the DTUK tuning box providing extra torque. The mounts are now a bit more rigid than stock which is a welcome upgrade.

[@apassionfortangling3671]

Thanks for the reply 👍

[@DoriFord]

Yeah, but not just use a hydraulic press and make it perfect, let it cure, then install? :)

[@ScottElliott152]

The way I did the reinforcement has worked well. Still going strong after all these years with no more engine mount failures.

[@adyscorner7513]

Not good. Sorry. I have already did it and the engine (Om651 Mercedes) vibrations are more strong felt inside the car than before this operation. That is because the mounts are not allowed to work upside down for the engine to feel smooth. That is my personal experience opinion. Leave the mounts alone or change them instead. Although your car will be like possessed. Anyway, I tried your solution.

[@ScottElliott152]

I did explain at the end of the video that it's not for every one. The trade off to have stronger mounts is more vibration. I've not had any more mount failures since reinforcing them. With 600Nm of torque I'm happy with the reinforced mounts.