M275 V12 Bi-Turbo Platform Technical discussion relating to models sharing the M275 V12 Bi-Turbo (V12 TT). Including SL600, SL65 AMG, CL600, CL65 AMG, S600, S65 AMG.
Sponsored by:
Sponsored by:

CL65 motor mounts / vibration Q

Old 03-07-2018, 12:15 PM
Thread Starter
Join Date: Dec 2015
Posts: 3
Thanked 0 Times in 0 Posts
2005 CL65 1987 560SEC AMG Widebody
CL65 motor mounts / vibration Q


Opinion requested regarding an '05 CL65 w/ 66k miles. Car has a whine / vibration, louder once car is warmed up than when first started. Not audible from outside the car but relatively loud from inside. Pitch is dependent upon rpm, sound was present before the following work was done.

In the last four weeks:
1. ABC pump has been replaced (legit as psi dropped to sub 20 bar once warmed up, around 192 bar while cold),
2. all ABC lines in the front end of the car have been replaced,
3. front accumulator has been replaced,
4. pulsation damper has been replaced.
5. Idler and tensioner pulleys have been replaced

Thinking motor mounts have collapsed sending vibrations through the frame.

But the odd thing is, the motor exhibits no visible vibration or rotational (torque) movement, either from an initial start (hot or cold) or from rev'ing the motor. Nothing. It acts like it is bolted directly to the subframe w/o any rubber mounting.

1. Is the lack of any visible engine movement normal for the 275?
2. Has anyone who has replaced their mounts have any guidance as to how to tell if the mounts are actually collapsed besides simply assuming at 66k miles they are going to be shot?
3. Other opinions as to what to consider?

Thank you in advance.

dgca00 is offline  
Old 03-09-2018, 03:38 PM
Junior Member
Join Date: Aug 2008
Posts: 69
Thanked 13 Times in 13 Posts
S65 GL320CDI GLS63 80 Series Landcruiser
Couple things from my experience. I have an '08 S65. I've an RPM dependent whine twice. First time it was the pulsation damper on the tandem pump. There was a fairly faint whine and most noticeable around 1,500 RPM. Above 1,500 I think it gets drowned out. Second time was much louder but intermittent and you'd hear it at all RPM. At 4,500 RPM it was a very loud. I replaced the front and rear accumulators which solved the problem. I've replaced motor mounts twice. First time I took my dad somewhere and he commented that the car seemed loud while we were driving. I think its a gradual degradation and I didn't really notice it but after replacing them the car was so quiet and smooth the change was amazing. The second time I did it after about 60K more miles just because I felt that was about the limit on the mounts. Didn't have the same effect so the mounts must have still been in reasonable shape. Never checked for any engine movement. Obviously with these engines you really shouldn't feel any vibration while sitting at idle.
UNderdog is offline  
The Following User Says Thank You to UNderdog For This Useful Post:
dgca00 (03-11-2018)
Old 03-11-2018, 09:51 PM
Thread Starter
Join Date: Dec 2015
Posts: 3
Thanked 0 Times in 0 Posts
2005 CL65 1987 560SEC AMG Widebody
Thanks UNderdog. Today had time to look at it again. This go around placed in drive, brakes on, and gun'd it a bit, motor mounts are shot, drivers side jumped maybe an inch and a half or so. At that point, just to make sure it is the source, took out the motor mount bolts and raised the motor up about an inch and a half. No noise at all, total quiet inside the car.

So, have my next project escalated up a bit on the schedule.

dgca00 is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: CL65 motor mounts / vibration Q

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.
  • Ask a Question
    Get answers from community experts
Question Title:
Your question will be posted in: