[deanrantala]

DIY: HOW TO REPLACE BAD ENGINE MOUNTS ON W163 ML500

UPDATE OCTOBER 27, 2020

It seems the sys admins who run this board had some issues with updates, etc... as a result, all the image links (which were stored on my own server) were mangled.

To make things even more dificult, there is a limit of 10 "attachments" per post and trying to re-link to the images directly (on my server) yields a "Error, contact sys admin". I am not even attempting to reach out to the trunk monkeys and hence will re-attach the rest of the missing images to another post a bit further down this thread.

THE REST OF THE PHOTOS CAN BE FOUND ON POST #85.

Sorry for the inconvenience.

****

Now before we get started...

I realized there were no DIY write ups on this procedure before I started. While I have Mitchell OnDemand and the MB SM at my disposal, I always like looking over others actual experiences with these types of repairs (especially with pictures). I quickly realized the net is kinda lacking when it comes to motor mounts for these particular cars.

Now my particular W163 is a 2003 ML500. While the V6 and earlier V8 will be somewhat different, this write-up covers the worse of them all as this model has the least amount of space to work in.

Some of the steps outlined in the MB service manual will also not apply depending upon your various vehicle. For example: it mentions removal of the viscous fan. My particular ML does not have a viscous fan: it is completely electric. So no need to remove anything in my case. I will try to explain as much as I can as I go along.

Finally, this job - on a scale of 1 to 10 - is probably a 3 or a 4. This is coming from someone who has removed engines, transmissions and rear ends. So I hope that gives you some insight as to the difficulty level of what you are about to get into.

TOOLS NEEDED:

18mm Open end wrench (gear wrench is ideal, but normal one will work)
18mm 3/8 drive socket
14" worth of 3/8 drive extensions
3/8 drive universal joint (swivel joint)
10mm 3/8 drive socket
16mm 3/8 drive socket
Small bottle jack
Some peices of cut 2x4
One can of Red Bull
4-6 Hours

Drink the Red Bull. While you are drinking it, you may wanna hop over to You Tube and find the Rocky theme song: play it and think about what you are about to get into for a minute......

...ready?

GETTING STARTED:

To begin, we need to completely lift the front of the vehicle off the ground as both front tires will be removed. Before lifting it up, do yourself a favor and break the tire bolts while you have the ground to hold the tire from turning.

Secure the vehicle on Jack stands. If you do not have jack stands, you can rest the vehicle on the tires you remove and place a couple strips of cut 2x4 between the tires and the frame to add needed height and protect the rims from damage.

With the vehicle off the front tires, remove both front wheels. Now the fun begins. Let's start with the hardest side: the driver side.

Before we can get to anything, we need to remove the inner fender cover. On my W163, this is held on by several nylon 10mm nuts.

Before removal:

After removal:

Notice in the image above there are two heat shields. Some models may have different heat shields, some may only have one (??). Either way, these need to come off, which will leave you looking at this:

Now we can get to the 18mm nut on the top of the motor mount:

Next, we need to get to the two bottom nuts. These are 16mm (or at least they were on mine) This is where your 3/8 drive swivel joint is going to help out. Both nuts can be accessed by running the swivel w/ extension up from the bottom just behind the CV joint...

Accessing the front-most nut:

Accessing the rear nut:

Accessing these two bottom nuts on the driver side may or may not require removing a small bracket that holds a power steering hose that is rather in the way. While it was nearly impossible to get a camera in there to show you, you will see what I mean. I removed the first of the two bottom nuts without messing with the bracket. For the second, I said "to hell with it" and removed the little bracket giving me more room to move the hose around for easier access to the nuts. Just take a look under there and do what you are most comfortable with.

Now that this is done, lets move over to the passenger side and remove the 3 nuts on this side as well.

As before, this is the passenger side fender well before removing the inner plastic shield:

And this is what you are looking at once the plastic shield is removed:


Getting to the 3 nuts on this one is stupid easy, more than enough space to move around and you can even use the socket and 3/8 inch drive for all 3 nuts (no extension needed).



JACKING THE ENGINE UP:

This is a debatable topic. While there are risks in jacking the engine up, you should be fine if you do it slowly and carefully. But before we start going jack-crazy, lets take a minute to look around the engine compartment and ensure nothing is going to bind or break if the engine moves more than a couple inches.

On my W163, only the air intake pipe (that runs from under the grill to the box) had to be popped off. Again, the service manual states removal of the fan - again, not needed in my case since my fan is electric. Also noted is removal of battery cable - I did not bother with this either as I see no need to do so: the engine is grounded with 2 separate cables and nothing will be hitting any hot wires that I can see. Regardless, take a look and use your best judgement, if something looks like it may not survive movement of the engine by 4 inches or so, remove it.

Finally, if you DO have access to an engine hoist, then use it. I did this write-up for those who want to complete the job with common tools in their back yard or the garage.

Lets start with the driver side:
image

Notice I placed a small piece of 2x4 between the back pad and the oil pan - this is to spread the weight of the engine evenly across the pan rather than from one area - THIS IS IMPORTANT! Do NOT try pushing the engine up without something between your jack and the oil pan!

Jack the engine up slowly and carefully. As you lift the engine up, you will hear some creaking - especially from the heat shields around the catalytic converters and exhaust down pipes. They have more give to them than you may think. Also keep an eye out on stuff on top the engine. Some W163's may have limited space between the top of the engine and the coolant tank, mine was tight, but had enough give that I did not have to disconnect the tank (even if you did, just remove the couple nuts that hold it to the firewall, no need to remove it).

Again, use common sense here.

Once you are high enough, you are ready to remove the driver side mount:
image

Here is a pic of the driver side mount removed and sitting next to the new mount:
image

Also take a moment to note that your mounts (new and old ones) are marked:
image

These mounts MUST be installed with the "FRONT" markings facing forward.

Pulling the mounts out are a pain in the arse. Putting the new one in is equally as frustrating. You may need to find something to do a little prying with, but it will go. This is perhaps the hardest part of the job!

Once the new mount is in place, DO NOT BOLT IT IN - we need to swap out the other mount first. Bolting the new mount down will limit movement of the other side.

Now jack the other side (passenger) of the engine up:
image

Again, it may take a little carefull prying to the the mounts to clear. This is a a real pain, but it will go:
image

The passenger side was not broken yet, but it was starting to separate and had limited time left as well:
image

Once the second mount is in place, lower the motor back down for the last time and you are now ready to bolt both mounts back.

Replace the heat shields, put the inner fender covers back, put the wheels back on and lower the car - you are all done.

 

[pte]

I'm glad you finish out this DIY. I had not discovered , until late into the job, that there was no real good description & Pictures of the procedure of R & R the motor mounts. For me removing the engine block mount casting made better sense , only because I did not jack the engine up from the bottom. I used a small cherry picker & pulled it up from the top. Your way is much quicker. I sure your input & effort will be greatly appreciated by the W-163 ML community . My Mounts never tore or delaminated . But got to the point were the A/C compressor vibration & Noised seemed harsh . My Power steering pump was the early suspect !! , but it is dead a$$ quiet . Changing the motor mounts & including the $44.00 Trans mount , has fixed the NVH
Many Thanks _PTEngineering

 

[johnma]

I remember that I had my done at the dealer under warranty, it was noted that one side bolt was frozen. Had to cut out.

 

[Mars478]

Awesome the is super helpful, as I need to do this job on my 320 soon.

 

[RJV]

Great write up, and photos thank you.

I'm not needing to do this yet, but having read through your write up there is one thing not clear to me.

On your first mount you jacked the motor up (up to 4 inches) under the oil pan .... so I would have thought the motor would be raised somewhat evenly on both sides. Then you removed the driver side mount.

But then you jacked the motor on the passenger side to remove that mount.

Can you just clarify whether the two stages of jacking .... was there a need to jack one side at a time (i.e. roll the motor slightly), or what was the purpose of having to jack the passenger side separately (or further)?

Thanks.

 

[Hirnbeiss]

Torque specs: bottom nuts 35 nm, top nut 55 nm

 

[copper_90680]

Great write up, and photos thank you.

I'm not needing to do this yet, but having read through your write up there is one thing not clear to me.

On your first mount you jacked the motor up (up to 4 inches) under the oil pan .... so I would have thought the motor would be raised somewhat evenly on both sides. Then you removed the driver side mount.

But then you jacked the motor on the passenger side to remove that mount.

Can you just clarify whether the two stages of jacking .... was there a need to jack one side at a time (i.e. roll the motor slightly), or what was the purpose of having to jack the passenger side separately (or further)?

Thanks.

I had done this myself and I found that jacking up one side at a time gives you more clearance to remove the mount. Since the other side was held down the free side goes up approximately twice the distance of movement at the center of the engine. It's just geometry. Good luck and enjoy the job my friend. I enjoyed all the busted knuckles and bleeding I got from that job (sarcasm). Make sure you have plenty of Bandaids.

 

[deanrantala]

Great write up, and photos thank you.

I'm not needing to do this yet, but having read through your write up there is one thing not clear to me.

On your first mount you jacked the motor up (up to 4 inches) under the oil pan .... so I would have thought the motor would be raised somewhat evenly on both sides. Then you removed the driver side mount.

But then you jacked the motor on the passenger side to remove that mount.

Can you just clarify whether the two stages of jacking .... was there a need to jack one side at a time (i.e. roll the motor slightly), or what was the purpose of having to jack the passenger side separately (or further)?

Thanks.

As copper_90680 points out, jacking it up one side at-a-time makes for easier maneuvering.

When removing the driver side mount, jack the engine up from as close to the driver side of the oil pan as you can.

When removing the passenger side mount, jack the engine up from as close to the passenger side of the oil pan as possible.

If you were to jack the entire motor up at once it would likely bind on a few additional things that have to be removed, much easier done one-side-at-a-time.

- Dean

 

[bjedruszczak]

Thank you for the write up.

It actually helped me decide to pay my mechanic to do the replacement. With my luck, I was affraid that I will get the rusty bolt stuck - and as it turned out, the bolt was rusty and stuck (ML320 with 190K ) mechanic did remove it using his tricks and tools. I would probably spent a week working on it.
Anyway, the reason for replacing the mounts (first time on this truck) was the engine vibration and rattle while stopped in a gear. At first, I susspected injectors clogged up, so I used injector cleaner additive for 3 months on every fill-up, but instead of improving it was getting worse. I also noticed a thud when stepping on a gas pedal while moving from the stop.

After reading this write-up and several others I did the angine mount test with one foot on the brake pedal and other on gas - it failed miserably. The engine moved up several inches when pressed on gas.
Now, after replacing both mounts the truck runs like new again. No vibration / shaking while stopped on traffic lights and no thud when moving from a stop.
BJ

 

[cinco]

If i was looking to get this work done at an indy repair shop, what would be a ballpark cost to preform this?

 

[43sqd]

If i was looking to get this work done at an indy repair shop, what would be a ballpark cost to preform this?

All this information is available to you if you would take the time to read the STICKIES on the main page of this forum.

The answer to your question depends on how much "your mechanic" charges per hour.

 

[td64]

I've never tried to jack up an engine from below, but see many others had. Is there not risk of cracking the pan, even with a solid block of wood to distribute the load?

 

[art_arev]

Not if done properly. The other option is to jack it from the tranny

 

[td64]

Procedural Modifications, ML350

Inspired by this, I set out to do it on my '05 ML350. It was largely the same, but I made some notes, esp. where I found differences:

1. Driver’s side mount
a. Single heat shield
b. Access to bottom nuts, driver’s side from front of CV joint.
c. Access to top nut not bad; used box-end wrench with normal small angle to clear heat shield mounting plate.
d. Removal of PS hose bracket pretty necessary for front nut & easy. Needed multiple wobble extensions & socket for rear nut.
2. Loosened xmsn mount bolts for extra float and to allow replacing that mount also.
3. Loosened fan shroud to prevent interference when lifting (two 10mm bolts & clips at bottom)
4. O2 sensor on driver’s side looked dangerously close to body heat shields. I watched it closely while lifting, but it never interfered with anything.
5. Disconnected short ground strap near pass. side mount
6. Limited access to oil pan, lack of a bottle jack, and concern over (small) risk of cracking, led me to rent an engine crane and lift from above. I needed a small clevis since the crane hook was too large for the engine lift hole. I found it pretty reassuring to be able to rock the engine side-to-side as I lifted it, to help insure I wasn't damaging something in the process. So for me it was well worth the $30 it cost to rent this.
7. As others have said, the only challenge is the driver’s side. I tried to use some engine “twist”, by loosely re-installing the pass. side mount first, then lifting against this downward force. In the end, I had to loosen these bolts considerably, and felt like engine height was being limited by various solid obstructions (probably cat. converters). I was very close to removing the engine-mounted bracket (and AC compressor to allow), but kept tweaking things and with come cajoling of the mount I finally got it installed. (I used offset pliers with some rubber-covered jaws to align the top bolt of the mount. I probably compressed the rubber a bit before it finally found the hole.)
8. Since I didn’t see detailed mention of it here, I easily replaced the transmission mount as well. I decided to lift via the transfer case (block of wood & a floor jack), as opposed to the pan. Removed 4 nuts from mount. Removed 2 nuts from frame cross-member, and loosened 2 on the other end to allow it to swing down.

All in all, this wasn't a terrible job -- just time consuming. Still, taking my time to make sure I didn't damage anything, I took probably 8 hrs, which probably netted ~ $50/hr. including planning -- enough for this shade-tree mechanic!

 

[DNLB]

Did mine on my 2001 ML320 in 2-1/2 hours, including the transmission mount, it's pretty easy when you have a step-by-step telling you how! Thanks a ton!

My driver side was completely apart, the passenger side & tranny mount looked ok, but I had them out & new ones in hand, so they got replaced. Now I just have to fight the urge to keep the old ones for "emergencies"....... I'm such a pack-rat!





Update: I should have taken my time, I discovered that I apparently cracked the top weld on my drivers side catalytic converter, now that is waiting to be welded up. Be careful how far you raise the engine!

 

[johnma]

I'm glad you finish out this DIY. I had not discovered , until late into the job, that there was no real good description & Pictures of the procedure of R & R the motor mounts. For me removing the engine block mount casting made better sense , only because I did not jack the engine up from the bottom. I used a small cherry picker & pulled it up from the top. Your way is much quicker. I sure your input & effort will be greatly appreciated by the W-163 ML community . My Mounts never tore or delaminated . But got to the point were the A/C compressor vibration & Noised seemed harsh . My Power steering pump was the early suspect !! , but it is dead a$$ quiet . Changing the motor mounts & including the $44.00 Trans mount , has fixed the NVH
Many Thanks _PTEngineering

Any one have the torque spec on those bolts securing the "engine block mount casting"?

Thanks.

 

[art_arev]

Any one have the torque spec on those bolts securing the "engine block mount casting"?

Thanks.

There you are

 

[johnma]

Thanks.
20NM + 90 degrees..

I have a broken engine mount on the driver side and getting ready to change them out.

 

[johnma]

I don't have engine hoist for this job. What's a good location to jack the engine to free the motor mount?. Oil pan using 2x4 and floor jack?. anyone have pictures for this job?

Thanks.

 

[43sqd]

Yes you can but the 2x4 must span beyond the edges (strongest part) of the oil pan.