w4sim

Hello all

The car was beginning to get very annoying to drive with a constant humming, hard suspension and general vibrations.

Just changed the Pulsation Damper a few days ago and what a difference that has made. The humming has gone and the suspension is feeling soft again. But the vibrations are still there.

Had it checked and sure enough the motor mounts seem to have failed. Was looking at replacing these but theres very very little information on how to go about changing them, just that the left one seems to be harder than the right one.

Has anyone got any clearer information on how to go about doing it?

Im a DIY mechanic and my friend is a full time mechanic so we're sure we can do this, but just need a few pointers. Will also replace the tranny mount at the same time i think.

Any help would be mostly appreciated.

awiner

Motor mounts are pretty straight forward. You will need a lift and screw jack.

I had to remove my exhaust from the down tubes back to get access to the mounts.

Make sure to have a wobbler on your drive extrusion, makes the job a lot easier.

w4sim

Thanks for the reply Adam, apart from the exhaust was there anything else that had to be removed or loosened? A few threads specify the ABC pump having to be removed, or the alternator to be removed from the other side?

Or is it just removal of the exhaust and then lift the engine up a couple of inches?

Thanks.

alx

If your mounts are not oozing oil they are prolly ok. Pick your battles.

Before redoing mounts check your driveshaft rubber cake. It is more fragile than the mounts especially on the v8 motors.

w4sim

Iv seen the mounts myself and cant see any oil, however the car has been shaking like a crackhead at idle ever since iv bought the car about 1 and half years ago. Im thinking if the oil has leaked out its prolly dried out by now and wont be visible.

Iv taken it to a reputable Merc indy and he's said the mounts are definitely shot. But i dont really fancy paying £400 (approx. $650) to have them replaced. I understand its not exactly a DIY at home kind of job, but like i said my friend is a full time mechanic so we have access to a pit, jacks and all the other essential tools.

Just dont want to lift up the engine and end up breaking something else in the process.

alx

read wis for procedure to properly nudge the engine a bit- i dont remember all the steps as the last one i did was couple years ago. if memory serves me right it needs to go up about an inch on your motor and about 2 inches or more on the v12tt motors. you will need to unplug/ remove a few things beforehand.

the hydraulic oil does not dry up very easily and it should stick there for a long time. get a screw driver and try to scrape a bit of the mount in question. if you end up with greasy residue- the mount is gone.

another non-scientific way to diagnose bad engine mounts is rev a bit at idle and have somebody watch the engine block- it should tilt momentarily just a very small amount and then come back very quickly. ofcourse seeing a few engines helps to set a baseline so your mileage will vary. bottom line is it should twist very little and come right back.

the tranny mount can be troubleshot by putting the car in gear and torque braking a bit (2000 rpms) and observing the motor. if it tilts backwards a bit and stays that way - the tranny mount is gone. it should drop just a bit and again- come right up. also tranny mount collapse is most easily identifiable when you are moving under moderate throttle and the drivetrain shudders when shifting. but be careful as the shift shudder can also be the driveshaft damper cake.

shake at idle should be approached carefully. it could be mounts, but it also possible that your car has learned garbage and engine adaptations need to be reset. if they are reset and shake does not improve it is possible that you need the idle smoothness procedure executed via das. only then if shake is still present you should suspect mounts. ofcourse i assume there are no misfires which are a whole different story.

v8mercedes

there is another easy way to check the mounts:

start the engine, shift from P into R, N into D, .....
Hear at the vibrations and listen if they are changing while you are shifting. if yes, you need new mounts.


maybe this helps...

w4sim

Thanks for the replies so far chaps.

The basics of the car are - 2004 S55, Full service History, 130,000 on the clock, lowered via lowering links, no real engine mods.

Alx - I too thought it was a misfire, such are the vibrations at idle, and at the last service had the spark plugs changed. Unfortunately made no difference. I had no idea that the engine idle smoothness could be reset, il speak to the indy and see if he knows anything about this. He certainly did not mention it at the time of checking the vibrations.

Just my line of thought really, but with the car at 130,000 miles im pretty certain engine mounts, tranny mount and even the driveshaft cake are all pretty much shot. I dont think they've ever been replaced before. I suppose a change can only help.

AMG 17GT

At that mileage yes.

Why not when it's all up in the air.

Good thread. Let us all know.

awiner

At 130k your mounts are shot leaking or not. Be careful when removing the mounts as my bet is you will get some of the oil on yourself

As to your question, yes the upper and lower oxygen sensor wires need to be un-clipped and removed when removing the exhaust. Not a big deal.

w4sim

If its just that then it does indeed seem straight forward, but im getting a few conflicting versions of what needs to be removed.

If i can get enough information out of you as to how to do it, i might take you up on your bet

Mercedes22

I had Engine Mounts, Gearbox mount and the Rear Trunion Bushes replaced on the CL55

It took my very experienced mechanic Four hours to fit the engine mounts and the gearbox mount and a couple of hours to fit the Trunions.

The engine mounts where £ 76.00 each + VAT and the Gearbox mount was £ 30.00 + VAT

The Trunions where £ 33.00 each + VAT

£ 377.00 + VAT Labour which equates to 6.9 hours

£ 248.90 + VAT Parts

He did say the mounts where half the size compared to the new ones. My CL had done 94,000 miles. The difference in the drive was amazing.

I live in Weybridge Surrey and the mechanic is in Horndean just off the A3 near Waterlooville

Great looking 220 by the way. You don't see many of S-Class 55's around. There is a W220 65 up for sale on Pistonheads I think.

Where are you in the UK ?

w4sim

Im in Bradford, near Leeds . . . so only on the other end of the M1 from yourself, lol.

I was kind of undecided between an S55 and a CL55 as i wanted a big luxo barge with plenty of power. But with me and my 4 brothers all being over 6ft tall the S55 was the one to have for rear space, plus they are rarer. If only they did a CL55 in LWB.

Many thanks for the prices, gives a rough idea as to how much i should pay if this doesnt work out. I really hope it does because what i can save in labour i will spend on extra parts to renew more bushes to make it drive like a proper S-Class.

w4sim

I find this bit particularly interesting as my thinking is that if they were half the size then the engine itself must have been sitting an inch or so lower than usual, and if thats the case then im sure it can move and inch or so up without causing any damage to anything. It must have some tolerance for abit of movement

w4sim

Iv just done this test on my car and sure it enough my engine is doing exactly the same thing, which goes back to my above post about movement. If the engine is moving that much by itself then im sure we can jack it up by that much aswell???

Mercedes22

That is some movement you have there. Definitely the mounts have gone.


Yes that's what you have to do. I was at the garage when they did all the work.

As mentioned he used a lift a screw jack to push the engine up.

He did the N/S front mount without having to remove any thing, still very fiddly though. The O/S mount was a little bit of a pain, the problem was trying to put the new one back, as it was twice the size.
In the end he had to remove that side of the exhaust. It took him the four hours.

I am a member of the MBClubUK www.mbclub.co.uk forum which is a great MB forum, lots of very helpful and knowledgeable people on there. I am C43AMG.

aabilla

to w4Sim- I have experienced the same symptoms- fount it was my transmission mount. $36 part. around 10 bolts to remove. Small jack to lift back the undercarriage. Might want to check the transmission mount. This took care of my vibrations. I replace my ABC hydraulic suspension with the traditional spring suspension. Got too tired with all the ABC issues. Rides like a flying carpet since the change.

w4sim

I have changed the motor mounts and the gearbox mount and the difference is definitely noticeable. However, there was still a bit of vibrations and a fair bit of shaking coming from the seats when driving. I knew it wasnt anything to do with wheel balancing as they have been balanced and all the front mounts were now new so it couldnt be anything there.

By coincidence i was getting the rear strut bushes checked for creaking when the guy decided to check all the other bushes around it (at my request) and found the rear subframe front bushes were so badly worn that they could be moved around with very little effort. Im sure at one point he was moving them around with his hands. Im now pretty sure this is whats causing the last of the vibrations so iv got brand new bushes from dealers and just waiting to get some time to put them in.

w4sim

I get a White "ABC - Visit Workshop" message on my dash just about every day now and according to STAR it seems that a valve is stuck closed in one of the rear struts, although all the struts were working fine when the Rodeo test was done

I am kind of considering going down the route of replacing the ABC system if and when the message turns Red, but from what i can gather the coilover kit is only good when going straight. Around corners its supposed to be particularly bad, any thoughts? And is it a strutmasters conversion kit?

Thanks.