Within the last few days my car has started to make a very worrysome noise under the hood. The sound is not normal to my motor and I has me quite worried. It sounds like there is a rock or something of the nature bouncing around in my water pump or in my timing chain cover. I do not know what it is.
I already have plans to change the timing chain in my car (90K) in the near future. If this noise is comming form my timing chain area I will do the job now.
Ok I have just a few questions,

1. Please tell me what you think noise is.

2. Can I remove the valve covers and replace them without changing the seals? (If so I will just wait untill I do the chain) Or can i replace the valve cover seals now and reuse them when I do the timing chain? (I would like to look at the timing chain, guide rails)

Ok now for the sound clips.

-----Rattle when in Park-----
-----Rattle when in Drive-----

The rattle when in Park (700 rpm) sounds almost normal, except one can pick up the noise of what sounds like a rock bouncing around in side of the motor. The noise appears about every second.

The rattle when in Drive (500 rpm) is much worse then the rattle when in park, the noise is much more frequent, it almost blends in but you can hear the noise if you listen to it. The noise is very ferquent happening many times a second.

The noise is only noticable at idel and sound particuarly bad when in Drive at at stop light or such.

BTW I do not think it is a oil tube because the noise seems to be comming form the water pump area.

Thank you for your help.

Subman

__________________
Factory trained Mercedes-Benz Technician
Look At My Website
-2002 C32
(E420 has passed away)
The best way to contat me is e-mail.

Sounds like timing chain slapping something inside the engine.

__________________
I got too many cars!! Insurance eats me alive. Dave

78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k

you beat me to it-that's exactly what i was thinking.hopefully you haven't broke off or disldged a guide rail in there

__________________
'95 s500 (bought for wife but can't bear to share!!!) 125kms
'92 legend 180kms
'88 tbirdturbo(fantastic car-only regular maint.)120kms
'87 mustang gt(gone)
'86 tbirdturbo(gone)
'85 mustang gt(gone-but not forgotten)

I had this problem in my 190E 2.6 with 90K mi. It was a rattling sound at idle or low RPM so my first thought was timing chain/guide rails. I found out that it was the small and short shock absorber for the serpentine belt. It's in front of the engine right in the water pump/thermostat area. The rubber bushing gets worn out over time. You can troubleshoot this by putting finger pressure on the top portion of the absorber or you can remove the bolt and install any flat rubber just to squeeze the top portion. The bottom part is not an easy jobbut the top portion is the one that wears out all the time. Hope this helps.

Dennis

Dennis,
Good diagnoses and remedy, but that does not apply to the
V8 .
They have no shock, but it could be a bad tensioner....

I am going to take a stab in a different direction. Check to see if the sound exists with the A/C compressor engaged and not engaged. Same symptoms when the a/c compressor engaged. Went away when not engaged. Turned out to be the compressor. This was on a 126 with the D4 compressor.
John O

I have checked the AC compressor, the noise is there if it is on or off. So that prity much eliminates it.
Subman

__________________
Factory trained Mercedes-Benz Technician
Look At My Website
-2002 C32
(E420 has passed away)
The best way to contat me is e-mail.

FWIW, when the water pump went out on my Nissan Quest it made a very similar noise.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

The sound is similar to the serpentine belt tensioner/shock that was failing on my 1991 350SD. Changed it out and the noise went away. The dealer mechanic told me about it when he walked by the car with it idling - kind of recognized the sound without lifting the hood.

Seems you have plenty of steps to go through to isolate the noise already. If more people listen to your noises, you will get more suggestions and you won't have any free time for the 4th of July celebration. Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Try using a mechanics stethoscope to isolate the noise. They are cheap and help in isolating noises. Just be careful not to get it wound up in the moving parts. The noise sounds like mine did when the water pump bearing was bad and the impeller was stricking the back of the pump internally. No leaks just noise.

__________________
Dave
88 300E 250K Sold
2000 C230K Totaled @104K
2003 ML320 156K Sold
2009 E350 4Matic Sport 46K Sold
2011 ML350 60K Sold
2014 GLK350 46k
2012 GL450 55K

I found out what it was.
It is the fan belt tensioner, I took off the fan belt and started the motor I did not hear the clicking so I knew it was not internal. While the belt was off i spun all the accessories to see if they sounded wiered. The tensioner had a clicking noise but spun fine.
I put the belt back on and started the motor useing a screwdriver I listened for the noise on the tensioner mount. Sure enugh it was there loud as ever. I could see the tensioner moving back and fourth in connection with the noise. I have found the problem now I need to fix it.
Thanks for your help.
Subman

__________________
Factory trained Mercedes-Benz Technician
Look At My Website
-2002 C32
(E420 has passed away)
The best way to contat me is e-mail.