Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 10-19-2017, 01:08 PM
lsmalley's Avatar
Registered User
 
Join Date: Oct 2006
Location: California
Posts: 1,877
Irregular knocking m103.

There is an irregular knocking coming that I can feel under driver side foot rest/floor. It is not constant or consistent. Very random in occurrence, it literally sounds/feels like someone knocking right under the bottom where the floor is. It is one or two knocks at random. Doesn't even sound like metal on metal. It's muffled so I only feel/hear it if I sit idling and have to have my feet planted on the floor.
__________________

1990 190E 2.6L
Reply With Quote
  #2  
Old 10-19-2017, 02:26 PM
ChrisArnt's Avatar
Registered User
 
Join Date: Dec 2009
Posts: 279
Is your motor jostling about?
Could be a tailpipe.
Get under there and find out what is loose.

Or a squirrel.
__________________
~~~~~~~~~~~~~~~~~~~~~~
You play nice and so will I.
Chris NJ
96 E300D, 71 Baja Beetle, 77 Convertible Beetle, 2003 Subaru Forester.
Reply With Quote
  #3  
Old 10-19-2017, 02:36 PM
ChrisArnt's Avatar
Registered User
 
Join Date: Dec 2009
Posts: 279
If you don't have ramps you can drive one side up on the curb and it will give you some clearance, or find a natural ramp in a parking lot to drive up to give you clearance.
Put the parking brake on!
__________________
~~~~~~~~~~~~~~~~~~~~~~
You play nice and so will I.
Chris NJ
96 E300D, 71 Baja Beetle, 77 Convertible Beetle, 2003 Subaru Forester.
Reply With Quote
  #4  
Old 10-19-2017, 02:57 PM
lsmalley's Avatar
Registered User
 
Join Date: Oct 2006
Location: California
Posts: 1,877
Motor seems fine as far as mounts and stability. Idle is really smooth. I'll get under it today with a pry bar. Could it be anything internally in the engine? like engine knock? Or I guess I wouldn't feel that on the floor board.
__________________

1990 190E 2.6L
Reply With Quote
  #5  
Old 10-20-2017, 08:49 AM
optimusprime's Avatar
Trevor Hadlington
 
Join Date: May 2014
Location: Worcestershire in England
Posts: 1,142
Is it doing this on the move ,or stationary ? If on the move check the main driveshaft centre bearing for play .Or the transmision bracket on the gearbox .
Reply With Quote
  #6  
Old 10-20-2017, 09:21 AM
oldsinner111's Avatar
a parent should die first
 
Join Date: Nov 2008
Location: bristol,tn
Posts: 5,087
Flex Plate might cause,or convertor.Bolts also get loose,on 617 diesels sometimes front crank pulley will get loose and make you think your throwing a rod.
Reply With Quote
  #7  
Old 10-20-2017, 10:03 AM
ChrisArnt's Avatar
Registered User
 
Join Date: Dec 2009
Posts: 279
You need to reproduce the sound.
Does it happen with the engine off but ignition on? Could it be a loose fuel line moving around because of pressure change? Just a thought.

This reminds me of two things... once I ran over a raccoon on the highway and it hit the car right where my feet were.... gross.

Once I bought a 1983 BMW 633 with a 5-speed (AWESOME CAR TO DRIVE!)
And the steering box mounts were broken so the previous owner used big U bolts to crank it down. It shuddered terribly braking at highway speeds.

This car also had bad camber in the rear, so the tires were worn to the steal belts on the inside. When you pealed out the car threw a shower of sparks... Again... Awesome!
__________________
~~~~~~~~~~~~~~~~~~~~~~
You play nice and so will I.
Chris NJ
96 E300D, 71 Baja Beetle, 77 Convertible Beetle, 2003 Subaru Forester.
Reply With Quote
  #8  
Old 10-20-2017, 10:05 AM
ChrisArnt's Avatar
Registered User
 
Join Date: Dec 2009
Posts: 279
Quote:
Originally Posted by oldsinner111 View Post
Flex Plate might cause,or convertor.Bolts also get loose,on 617 diesels sometimes front crank pulley will get loose and make you think your throwing a rod.
Flex plate would only thump when you put in gear... Right? Not at idle.
But then again the trans is right there by you driver foot right?
Could it be a loose trans cooling line?
__________________
~~~~~~~~~~~~~~~~~~~~~~
You play nice and so will I.
Chris NJ
96 E300D, 71 Baja Beetle, 77 Convertible Beetle, 2003 Subaru Forester.
Reply With Quote
  #9  
Old 10-22-2017, 02:37 AM
lsmalley's Avatar
Registered User
 
Join Date: Oct 2006
Location: California
Posts: 1,877
It could've been gasoline. I ended up getting a different brand and it seems knock is gone.
__________________

1990 190E 2.6L
Reply With Quote
  #10  
Old 10-27-2017, 10:13 AM
Registered User
 
Join Date: Mar 2003
Location: Southern California
Posts: 2,063
A likely cause of such a noise is deterioration of the driveshaft center bearing pillow block, which will allow the driveshaft to flop around.

My center bearing and pillow block were replaced on warranty at about 40K miles because the bearing had spalled and was making a growling noise.

At about 80K miles my 190E 2.6 developed a squeaking noise from underneath. It was most noticeable at about 15 MPH. With the car on jackstands and the catalyst heat shield removed I was able to reach up, grab the driveshaft, and wiggle it around, and then saw that most of the pillow block rubber was gone.

Detonation is most likely to occur under low rev/high load conditions and will be more prominent at high coolant and/or ambient temperatures and won't sound like its coming from under the car.

Duke
Reply With Quote
  #11  
Old 10-27-2017, 10:19 AM
lsmalley's Avatar
Registered User
 
Join Date: Oct 2006
Location: California
Posts: 1,877
Interesting, once I changed the fuel, the knock was gone and hasn't returned. However, last night I did replace my support bracket because I know my driveshaft has been off balance and the rubber was deteriorated. The knocking occurred when I was stationary and there was no movement so I had ruled out the bearing even though I knew I needed to replace it. Finally got around to it last night, but I know it will need replacing again until I get the shaft balanced.
__________________

1990 190E 2.6L
Reply With Quote
  #12  
Old 04-18-2018, 10:13 AM
lsmalley's Avatar
Registered User
 
Join Date: Oct 2006
Location: California
Posts: 1,877
Irregular knocking m103: RESOLVED

So this irregular knocking was actually the bottom portion of the harmonic balancer skimming the top of my sway bar (400E), problem was resolved by adding 2 bump spring perch pad and lifting the front end a bit.
__________________

1990 190E 2.6L
Reply With Quote
  #13  
Old 04-18-2018, 11:16 PM
sixto's Avatar
smoke gets in your eyes
 
Join Date: Jun 2000
Location: SF Bay Area
Posts: 20,229
Sounds like it’s time for new engine mounts.

Sixto
98 E320s sedan and wagon
Reply With Quote
  #14  
Old 04-19-2018, 08:34 AM
Registered User
 
Join Date: Jan 2018
Posts: 222
Yup, amazed me how compressed my mounts were when I changed them out. At least 1" lower than the new ones.
Reply With Quote
  #15  
Old 04-19-2018, 09:18 AM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 7,973
Quote:
Originally Posted by sixto View Post
Sounds like itís time for new engine mounts.
... and, removing the W124 V8 sway bar, and installing the proper W201 Sportline / 16v sway bar.

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 03:40 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page