Anybody have any ideas?????????

[intruder]

I have a 1998 E320 wagon with 48,000 miles. It has a mild "knock" from the engine that's most evident when cruising or mild/moderate acceleration. (my wife drives it or I would have found it sooner) It's smooth as a bell at idle and during full acceleration. It's a little quieter during deceleration. Braking or turning have no effect. I added a bottle of Chevron Techron and changed fuel brands, but they had no apparent effect. I had the leveling system and drive-train checked at the dealer and it's fine.

I'm taking it into the dealer next thursday but, what else should I try or look for to help the mechanic diagnose this?

It almost sounds like it's not running on all 6 pistons or only 5 plugs (or would that be 10 or 11 of 12 plugs since it has 2 plugs per cylinder?) or like the dull popping noise of some inorrect valve overlap (but only on one cylinder.

Any suggestions would help>

Intruder

the new v-6 has had a few problems with cams and sometimes lifters.if this noise could be classified as more of a ticking, this is probably the case. as a side note, use only mobil-1 or valvoline synthetic 0w40 in this car if you plan to keep it past the factory warranty!

[RunningTooHot]

I hope that’s a typo Hazette – 0-40? Either that, or Intruder lives in the Artic (or Antartic). In the Valvoline synthetic line, I don’t even think there is such a beast as 0-40. Maybe I’m wrong, but I wouldn’t be using it unless Santa Claus lives in the neighborhood.

[Kuan]

OK Hazette, I'm going to make a request. I'm not trying to be argumentative here, but could you please explain more about the problems you describe? I've heard the M112 has had problems with a "soft" cam. Another rumor, and only one substantiated claim to my knowledge, is a problem with the harmonic balancer coming apart.

Kuan

[intruder]

Thanks for the responses.

BTW... I always use premium unleaded, either 92 or 93 octane and always use synthetic 5W30.

It is NOT a pre-ignition ping; I know what that sounds like. The knock (or dull popping) is NOT present at idle. Only during light or moderate acceleration. If you know what a car sounds like when the valves are starting to overlap you'll know the sound I hear.

Intruder

[smk_texas]

Try Lubro Moly -Ventil Sauber - valve cleaner - specially made for Mercedes. You may find it at ************************. It is $4 ea. I've used it on my 92 190e -2.6 and BMW 325e and it definitely helped.
smk_texas
92 190e 2.6 (97K)

[Kebowers]

two things I know that might make such a sound as you describe (dull low pitch not too loud, cruise only,) are a loose rear main bearing or loose flywheel/torque convertor or front vibration dampener.

It won't get better for sure.

[intruder]

thanks kebowers!

[G-Benz]

I concur with kebowers as well, those noises can be caused by the components he described, but with the low mileage???

Maybe at 148,000 miles, but 48,000??? Seems odd. Was the car formerly used by U.N. peacekeepers in Yugoslavia?

Originally posted by G-Benz
I concur with kebowers as well, those noises can be caused by the components he described, but with the low mileage???

Maybe at 148,000 miles, but 48,000??? Seems odd. Was the car formerly used by U.N. peacekeepers in Yugoslavia?

Hi,

I just joined this board,

I have the exact same problem as well, except mine is a little different, it only makes the noise when at idle

it a slight kind of knocking/pinging which is low pitched and very quiet

i also have another noise when the air conditioner is on, it is kinda of like a metal rattle, it is quite loud

the third noise i have herd is with the front drivers side suspension, it makes kind or a squishing noise when you go over a bump

are any of these related?

any help would be great

Thanks

Forgot to add that this is on a 1997 E320 with just under 80k miles

[Edited by CarFanatic on 07-01-2001 at 12:46 AM]