W202 C240 Noisy Engine

[design guru]

I have just done an oil change and was hoping it would remedy the rough noise that my engine makes when it starts and is running. Its a C240 W202 1998 and currently it sounds like a diesel when it starts up and while it ticking over. It runs absolutely fine and the gear change is fine. The noise does not get louder when its driving or if you kick down.

Any suggestions as a good starting point to eliminate the problem?

 

[BlackC55]

What sort of noise is it? Bearing type noise? Squeak ? A tap tap? Etc

 

[horgantrevor]

hydraulic tappets i would say

 

[design guru]

What sort of noise is it? Bearing type noise? Squeak ? A tap tap? Etc

Its hard to describe, but I would say a tapping but I guess it one of those things unless you heard it its quite difficult to diagnose.

 

[dog68]

Can you record the sound?

 

[Haris]

As above one of your hydraulic tappets is probably sticking. Try some wynn's hydraulic tappet treatment from halfrauds.

 

[Adam230K]

is it a raspy sound? almost like a metallic noise? could be your catalysts if it is

 

[R.Sendout]

You say it sounds like a diesel?
Tappets would be more of a 'tick' noise than a diesel like 'knock'. And they usually shut up at higher revs.

Try and record it and post on here, I'm sure someone will be able to identify it

 

[JonathanC250]

Might be way off here, but check your shock absorber for the belt tensioner, mine had come away from the bushes and the noise it created was suprising for such a small thing.

 

[horgantrevor]

the manifolds can crack also on the v6 engine i replaced the two of mine the noise drove me mad for months till i took the car apart to find the drivers side back area of the manifold had a crack

i got two off the net in germany

record the noise and post it youll get a answer for sure then

 

[Auto-mobile]

I had a slk320 v6 the other day big end bearing had gone!

 

[brucemillar]

I had a slk320 v6 the other day big end bearing had gone!

With the big ends gone did you see any other symptoms apart from hearing the noise? Any smoke. My 240 V6 sounds like it has a cracked manifold and also has a misfire. Car is curentlty off-road awaiting funds. Mine starts and runs but will stall out if you try and rev it.

 

[Auto-mobile]

Noisy, slight misfire/poor running but no smoke

 

[design guru]

I have managed to find a car with similar problems and they have a video which demonstrates the sound.

1998 Mercedes c230 Engine rattle - YouTube

Although mine is a c240 its the same sound

 

[brucemillar]

Did you ever get this sorted?

 

[horgantrevor]

it sounds like hydraulic tappets i bet but maybe the timing chain needs replacing or the tensioner

i have a c240 that on start up has a tapping noise it goes away in a few min i know its the hydraulic tappets it used to be worse but i change the oil regularly and use a good quality oil

 

[Jit C240]

On my C240 I had a similar noise last year. Turn out, one of the pulleys and tensioners needed replacing.

 

[design guru]

Did you ever get this sorted?

I never did get it sorted, still using it and its running fine. Tried the wynns valve release oil and it did not make any difference. Had an MOT an they just described it as an 'Alien Noise' coming from the engine. I will look at the week end as quite a few have mentioned the belt wheel. I did get told the power steering pump has a slight oil leak. Could be linked

 

[brucemillar]

My 2004 - W203 240 is still off the road since it decided to cut out on the Motorway. Refused all efforts to re start. next morning it started first turn (and still does) but is sounds like a bag of spanners and will not rev (it stalls if you try and rev it). It also sound very much like the exhaust manifold is blowing (very loud and deep exhaust note)

I am baffled as to what this could be. Some suggest dropping the exhaust as it may be a blocked cat? but would that generate a misfire? and why will it not rev?

I have removed the MAF with no difference.

 

[horgantrevor]

best thing to do is get it hooked to a star machine get codes read it could be many things