Methodology to check motor mounts? - PeachParts Mercedes-Benz Forum

pcmaher · #1 05-26-2004, 08:09 AM

...check for worn motor mounts in a 95 S600 W140 body? Can't find this info in my manuals, and a quick visual from below doesn't show any obvious signs of wear.

pcmaher · #2 06-04-2004, 04:15 PM

Could use some help here. See original posting above...

Ethan · #3 06-04-2004, 07:59 PM

do a search on this site for motormounts,

you can go under and measure the mounts to see if they have collapsed.

or actually slightly raise the engine with a protected floor jack and see if vibrations or noise abates

what is your mileage? and what makes you think your mounts are bad?

is your engine maintained? and you don't have a tunning issue?

mercmad6.3 · #4 06-05-2004, 07:40 AM

I usually just change mounts on any Merc. that I work on.As arule you cannot see the wear on the mount until it is removed and placed alongside the new mounts.if you suspect flattened mounts ,check oil leak issues as even power steering fluid will rot rubber. look at the exhaust manifolds and see if they are close to the steering etc,dead mounts will locate your engine so that it is too close to "any thing important."

pcmaher · #5 06-05-2004, 08:54 AM

Unsure of how to measure for collapse, as I have no data for good mounts to compare to. Engine is tuned. I get a slightly rough idle, but as soon as engine is spinning above idle, it goes away. Torqueing the engine at a stop eliminates the roughness. I suspect that if it is bad motor mounts, torqueing the engine is lifting it clear of any hard contact points. I had thought of lifting the engine as Ethan suggests to ensure it was not resting against the frame. Good idea, I will try that. I will also look for oil leaks, but if I remember correctly, it was very dry last time I was under the car. The car has 120K on it, and I do not know if the previous owner ever changed mounts. I think I'll change them. Are there any special precautions I should take when changing them, or is it a straight-forward job?

pcmaher · #6 06-12-2004, 07:27 AM

OK, here's the latest. Let me start by saying that MB didn't make it easy to change motor mounts under the V12. Mermad6.3 is absolutely correct, you cannot see if the motor mounts are damaged while they are in the car. Not a good design, there should be some visual way of telling. Let's move on...things that have to come off to get to the mounts...
1) Air filter intake scoops.
2) Air filter housing assemblies.
3) Mass flow air sensors.
4) Oil dipstick tube, remove fastener at opening, and remove bolt down by pan. Still cannot remove the tube, but at least it can rotate enough to provide the necessary clearance.
5) Coolant overflow hose.
6) Radiator fan shroud.

That's all I can remember for now. NOTE! The oil pan is not as stiff as old American oil pans. Even though I used a 2 x 4 on top of my floor jack to protect the oil pan, it still bent slightly. It would be a good idea to cut a close-matching piece out of 2 x 8 or 2 x 10 for better support. Message too long, see next post

pcmaher · #7 06-12-2004, 07:33 AM

Message continued...I had to grind down the height of a 17 mm socket to get to the top bolt. Once the bolts were removed, the mounts came out pretty easy. You will have to turn the front wheels to get the steering linkages out of the way. BE CAREFUL, the mounts are a funky shape, and will fall out without warning even if they seem to be stuck in place. Once the old mounts were removed, it was obvious that they needed replacing. The inner portion on both mounts was sheared from the outer portion. It's no wonder I felt vibration at idle. I also marked the oil pan to get a height indication. I looked at it after I got the new mounts in, and the motor is at least 3/4" higher than before. I didn't finish buttoning it up last night, but I'm close. Should finish today. Will let you know how it feels with the new mounts.

pcmaher · #8 06-12-2004, 07:35 AM

One more comment to the above...I strongly suggest you change the oil filter while all the intake stuff is out of the way. You'll have a clear shot at it. Talk about a bad place to put the filter.

Hatterasguy · #9 06-12-2004, 06:43 PM

pcmaher my friend just got a 1995 S600, where is the oil filter? Can you drain the oil or do you have to suck it out of the dip stick? This is one complicated car!

pcmaher · #10 06-12-2004, 09:49 PM

Hello Hatterasguy,

The oil filter is located on the driver side of the engine, under the air filter box. I can send you pictures if you send me your e-mail via private message. The air scoop, filter housing, and mass air flow sensor have to come out. If your friend is not comfortable pulling these items off, have a qualified mechanic do it. If you damage the mass air flow sensor, you're looking at ~$550 to replace it. IT'S VERY FRAGILE!! Mercedes-Benz engines are designed to allow engine oil extraction from under the hood via the dipstick tube. Engine oil can be extracted using the dipstick tube.

Note: Inserting tubular probes through the dipstick tube is NOT recommended.

Engine oil drain plugs are in place, but access to them may only be possible with the removal of engine compartment trim or noise encapsulation panels.

The filter element sits inside a permanent housing bolted to the engine. Just replace the element. Good Luck!

pcmaher · #11 06-12-2004, 10:21 PM

Changing those motor mounts sure made a difference in smoothness. Now THAT's how a V12 should feel. Can you feel it running? You say you don't feel anything? That's the way it should be

Hatterasguy · #12 06-13-2004, 02:45 PM

Thanks pcmaher I'll give you my email. I'm trying to help him figure it out, it is an awsome car, 65k miles, silver on black. He is the 3rd owner. They feel like an electric car don't they! Maybe the dealer would be the best bet for the oil changes. Or possibly Jiffy Lube.