w202 c250td - engine niose

[ozzy1000]

hi all,

newbie here... I have just bought a nice old 1998 c250td classic, the car was cheap as chips and came with no service history, i test drove for a good hour or so, everything sounded ok, no rattles, quite a nice smooth old diesel for a 99k car...

got it home, drove about 300-400miles through the week and then did a service myself on the following weekend (first oppotunity). it was over due a service according to the display, so I did an oil flush and oil filter, oil, air filter, fuel filter. I had a slight faff with air in the fuel filter as the VW's I've had will just fill the filter themselves and run, but with the merc I had to manually fill the filter. other than that fine... however, since the service the engine has developed a quiet but definate rattle that wasn't there prior to the service!! ... its at engine speed and is intermitant, somtimes it seems to go away slightly but is quite present from cold and often when warm...god forbid; it almosts sounds like somesort of top end bearing??? but then why has this only just started post service?? maybe an injector, somthing related to the fuel fitler change?? the only other thing I can think of is it might be that the oil is a different viscosity?? i used fully synthetic as per the parts dealers computer system... 5w-30 I think??

any advice is very welcome,

Owain

 

[124fan]

My old girl has always had Shell 10w 40 semi, at 10k mile services, now has 287k miles and still runs great with no oil use.
I will be sending her to the scrap man in a few weeks as mot runs out!

 

[streethawk]

My old girl has always had Shell 10w 40 semi, at 10k mile services, now has 287k miles and still runs great with no oil use.
I will be sending her to the scrap man in a few weeks as mot runs out!

Sorry to hijack but has your car got 3rd led brake light in the rear window as I'd buy that if your scrapping her! Can't get one anywhere. Ta Carl.

 

[streethawk]

Sorry to hijack but has your car got 3rd led brake light in the rear window as I'd buy that if your scrapping her! Can't get one anywhere. Ta Carl.

Oh forgotten is it a saloon as that's the one Iam after for my w202.

 

[ozzy1000]

My old girl has always had Shell 10w 40 semi, at 10k mile services, now has 287k miles and still runs great with no oil use.
I will be sending her to the scrap man in a few weeks as mot runs out!

thats impressive mileage! a mechanic mate of mine said 10w 40 would be cheaper and totally adequate... maybe next time..

Since I wrote this post I've found this thread;

http://www.mbclub.co.uk/forums/engine/94650-c250-td-injection-hoses-issue.html

there's a little video on the above link and this is exactly the sound! an intermitant pinking type sound... which leads me to believe there's either air getting in to the fuel system or an injector dribbling abit... either of which I'm pretty happy about it, the cars pulls really nicely and sounds fine at anything above idle so it's a relief to think there's an explaination beyond somthing critically mechanical...

I'll start investigating the fuel lines.. I may have disturbed somthing during the service or maybe the fuel filters not sealing properly??

 

[BlackC55]

Try a strong dose of injector cleaner on a 1/4 of a tank. Then take it for a good blast

 

[Dieselman]

It should be a 40 weight oil, but the rattle is probably nothing.

Rev the engine and allow to drop back to idle. If the noise stops when on the over-run, until fuel comes back on at ~1200Rpm, it is combustion related.

 

[124fan]

Sorry to hijack but has your car got 3rd led brake light in the rear window as I'd buy that if your scrapping her! Can't get one anywhere. Ta Carl.

Sorry, non on my car.

 

[streethawk]

Sorry, non on my car.

Ok thanks.

 

[ozzy1000]

It should be a 40 weight oil, but the rattle is probably nothing.

Rev the engine and allow to drop back to idle. If the noise stops when on the over-run, until fuel comes back on at ~1200Rpm, it is combustion related.

thanks, yep that's it, I've just been out and revved/listened , no rattle at all beyond about 1200-1300 rpm, not only on the over-rev but on anything above around 1200, but then as it comes down to idle it starts chattering again.... I wonder if its just coincidence that it started around the service or whether I have air coming in somewhere?? do you have any advice on dealing with this??

also; my mistake, I meant 5w-40 not 30, it has 5w-40 in it at the moment.

thanks,

Owain