Motor mount replacement questions
 

Ok, car is 99 E430
Shop advises motor mounts need relacement. $455 parts and labor.
1. Does this price seem excessive?
2. How many engine mounts are there total?
3. Are there any "special" tools that need to be purchased to DIY?
4. Anyone have DIY tutorial?

This price seems very high. I was wondering what the parts price would be and if it would be possible for me and a buddy to do it, then labor would only be pizza and bear :D

Unless MB changed them since the W124 chassis, the engine mounts are pretty simple IF you can reach them!

They are gell filled, with a bolt in top and bottom. YOu will have to be able to reach both the top bolt AND be able to grasp the mount, plus you need a floor jack to raise the engine up off the mounts while changing them.

I suspect the V8 mounts are a huge PITA, equivalent to the right side mount on the 300D -- burried under the turbo, completely inaccessable from above, so you end up putting the car on jack stands and working from underneath in very restricted space.

Take a look and see what you are in for -- the price indicates about an hour or two of labor (list price on the mounts is $100 each, I think), so it won't be too bad so long as you can actually reach the mounts from below and get the top bolt loose.

Peter

This site sells them for $85.79 each.

Haasman

99 E430 what kind of mileage and symptoms cause you to need new motor mounts.

I am not doubting the diagnosis, just curious the symptoms.

Shop indicated that motor mounts were nearly collapsed and recommended replacement. This was the only information provided to me.
I don't see any symptons. I have read that one sympton is a knocking noise after acceleration and the torque of the engine jerks the engine up, and the engine falls back down.

Sounds like the symptom is that they need the money. I certainly wouldn't replace them until there's some sign that they are a problem. Or if you're worried about get a second opinion. The price sounds a little high but not terrible - it is a tough job on a V8.

"Seeing is believing" ..... have your shop show you why you need new mounts.

Haasman

Motor Mount
 

When my 300e motor mount went out, the car had a very noticable vibration at idle, almost like an ignition miss. In motion nothing felt unusual.

The mounts are glycerine filled and when the fluid leaks out they collapse very slightly lose their ablility to absorb vibration. I noticed some grey colored fluid on the garage floor.

Changing the right side mount on my 300e was very simple. The V8 engine might be a different story. My right side mount has failed twice and the left side is still original as far as I know.

Mounts are pretty common thing to replace...

If the car needs mounts- check the flex discs too=) There was a thread a while back about the aftermarket mounts not being fluid filled? Something like that- anyhoo you should insist on mounts from the dealership.

I've never found it overly difficult to r&r mounts. Depends on your tool selection at home. Short 1/4 drive allen wrenches are a big help to get into small places (stallwillie) and you may need a couple extension combinations. Need a 8mm (?) for the bottom bolt. Make sure you don't mess up the cap screws or you will really hate getting them out!!!

I believe there is a standard way to measure the mount height.


Michael

For the 300E/M103 engine I believe it is 13mm of clearance between the lower metal lip of the mount and the crossmember it rests on.

Is it ok to lift the engine up with a jack/2x4? Or better to hoist it up?

Either way is fine. To the earlier comment about getting them from the dealer - not an issue - Sachs mounts are available aftermarket and perhaps some other OE vendors. The V8 is quite a bit more difficult than the straight sixes - there's just not as much room.

I did the ones on my E320. I also replaced the transmission mount while I was at it. It made a huge difference. Both motor mounts were worn out.

I followed the instructions I found with some searches on this forum. The right one was easy to clear. The left one was harder. I can't speak for the V8 though, might be tight. $455 doesn't sound "excessive" considering the retail price for the mounts and typical hourly labor rates.

Yea, maybe the price isn't excessive. I was a little corn-fused, as I was looking at the picture of the listing for the motor mounts on shopforum and was thinking that 85.79 was for the two mounts listed, which was why I was asking how many mounts there were.
I'm going to throw the car up on a lift and try to take a look at the mounts. I'm certain that after several beers my buddies and I will be convinced that we can do it. :D

Motor mount replacements
 

I wouldn't be so surprised that your motor mounts need changing. Looking back at some past MBs of mine, my '85 190E'S mounts were replaced twice during the warranty period (50K miles) not to mention the front flex disc. The '89 190E 2.6's mounts were changed three times (one flex disc) and the '95 C280's once. Proving that component longevity has improved a lot, my '01 C320's mounts and flex discs are still OK at 33K miles.

Just to show you how lucky you are, my Porsche 944's right mount has been swapped out nine times. Left side five times. All in 52K miles and 22 years.

I still think all these mounts come from the same place, the Stuttgart Motor Mount und kartoffelen werke.