My C230 sounds like a diesel when cold
 

I have a '97 C230 which sounds like a diesel when the engine is cold. As it warms up, it sounds just fine. Just wondering if this is normal?? I describe the sound as a diesel because several people have asked if it is a diesel when I fire it up.

Thanks.;)

Re: My C230 sounds like a diesel when cold
 

Cehck the oil level. The hydraulic cam-follower pin may not get sufficient oil when cold.

I had the same symptoms with my 1997 C230 at about 70,000 miles. It turned out to be a part in the water pump starting to seize.

Could be the air pump gone bad...
 

Disconnect the relay to the air pump next time it's cold to see if this is the culprit.

Good luck


~Paul

Follow Up
 

I brought the car in to the shop to have it looked at. There doesn't appear to be any problems with oil levels. What they have told me is that the belt tensioner shock needs to be replaced. Does this make sense and will it rectify the problem?:confused:

Did you leave it overnight so that it would start up cold?? Or was the engine warm when they diagnosed it?

If it was the tensioner shock, it would make the noise all the time, not just when cold. The air pump only runs for the first 30-45 seconds on cold startup until the cat converter is sufficiently warm to do its job.

I had the same EXACT symptoms as you on my 300E and it turned out to be the air (smog) pump bearing gone bad. I simply disconnected it.

Good luck!

~Paul

Paul:

<<
I simply disconnected it.
>>

How did you do that?

TIA.

Bo:

Just follow the wire leading from pump towards wheel well and you'll find its 2 pin connector. Voila, disconnect.

G'luck

~Paul

Last night my car sat outside for 3.5 hours at -29 while I was in a meeting. (the C230)

When I started it (unplugged) it most definitely did NOT sound like a diesel. This is not normal.

The M111 mill is not the quietest engine made, but not THAT noisy.

Other than confirming this is not normal, I have no solution, as it is too hard to tell you something without:

1. Where is the noise coming from?

2. How long does it last?

I can tell you this will be practically impossible to diagnose via this forum. You will need to have a tech replicate the problem.

My 190e 2.3 also sounds like a loud diesel under the following conditions -

Under light load between 1,000 and 1,500 rpm , whether hot or cold (it makes no difference) i.e. in drive with brakes on but light accelerator will generate the most noise.

The sound definitely comes from the valve train and has been there since I purchased the car.
Recently I have had the Head rebuilt , new chain and tensioner and it has made no difference - possible a bit worse now !.

The rockers and camshaft are all o.k.. My mechanic says that if it was due to wear in the cam or rockers and the Hydraulic lifters could not adjust for the wear then it would be noisy all of the time.

I heard another 190e 2.3 last week take-off at the lights and it also made this horrible noise at low revs.

Any ideas ?

Doug

Doesn't sound like a diesel anymore
 

The sound was in fact as a result of the belt tensioner shock. It's been replaced and the engine sounds like it should; nice and "relatively" quite.:D

My 1998 C230 (M111, non Kompressor) had the same symptom. It got so bad this weekend that I decided to take it to my independent MB Tech for evaluation.

The car has 112,500 KM and it does not have the updated belt tensioner with shock. This was easy to conclude since the shock was non-existent.

I bought the updated Belt Tensioner along with the shock, thinking it maybe the culprit, before I drove to see my Tech. Once I got there, he took a quick listen, stopped the engine took the drive belt off and he immediately spun the water pump. Voila - needed a new one!

He did say, as was mentioned in this forum, that the tensioner is usually the culprit. However, I was quite suprised it was the pump - especially with the car's mileage. He changed it and I had him install the the updated tensioner. The labor was a non-issue but the MB waterpump was a little painful - $ 300.00 CDN!

The result was worth it though - the car sounds MUCH quiter. :) :) :eek:

I alos had success in fixing the sound.

Apparently it wasn't the belt tensioner but rather a little shock absorber that connects the engine to he body (I assume it assists the engine mounts).

This might be peculiar to a M102 230 motor in a W124 chassis.

Doug

Nope. My 1998 C230 (M111.974) W202 chassis has the little shock, and it has indeed worn out on my car. When the eninge is cold, and the shock is cold, it can make a rattly noise. Also, the tensioner itself can make some knocking noises, though mine just let the belt squeal a bit when going bad.

same thing on 190E
 

I had the exact problem on my 190E, but the sound was there only on idle speed and it came and went, but only when cold, once it warmed up, you never heard it again. It was the tensioner shock for the serpentine belt, I ordered a new one and replaced it as well as corrected the way it was installed since it was not done correctly. Never heard the noise since that time.
If anyone is interested, what I noticed is that the tensioner would vibrate very aggressively when on idle speed, but it smoothed out on higher rpms, that vibration was what caused the noise combined with the worn tensioner shock.

xp