E300 poor start and engine noise

[colywoble]

Hello everyone,
Firstly I must say how usefull this site has been to me, a new to Mercedes owner.
Secondly, i have a few issues with my recently purchased 140,000 not so well looked after 1998 E300.
Poor starting.....I know this subject has been well covered here as l've read most of the posts on it!
I have replaced all the glow plugs as the light was staying on and they were all open cucuit and carried out a full service, but i'm left with a consistant starting issue.
Air in the fuel lines....but no evidence of fuel leaking. It will start in the morning after about a minute or two of cranking, i drive 15miles to work, it stays there all day and starts fine untill the last couple of days) in the evening.
I have replaced the 'o' ring at the inlet to the pre filter, but seemed to make little difference...the odd time or two, it has started fine!
Also , I did notice the rubber fuel lines under the inlet manifold are perished.
Is it possible that the fuel lines, seals and joints can let air in but not allow fuel to leak out?

The other , slightly worrying issue is an engine noise.
Most notuicable at idle, light load and low rpm over run. sound like a deisel knock, will almost dissapear if the idle is raised slightly (500 upto 750).
I was aware the timing chain should be replaced at 100,000m and the previous owner told me it had, but my investigations say otherwise.....could it be incorrect timing due to a slack chain?

Any help is a help....thanks

 

[Smiley]

Yes worn seals will tend to suck air in rather than leak diesel out due to the effect of the vacuum. It is worth replacing all the fuel lines if they look old they are not too expensive.

re the noise doubt that it is the timing chain - if the car has had regular oil changes then the chain will last for several hundred thousand miles; it is not a maintenance replacement at 100k.

more likely the noise is diesel knock - mine does it sometimes - not sure if there is a fix or giving it a good blast and thrash when it is hot will help? The other cause of the noise could be the poly v belt tensioner assembly - the mountings wear and it chatters at idle and sounds terrible - but it is quite cheap and easy to replace.

 

[colywoble]

Thank you for your reply,
I have Emailed my local MB dealer to price the relevent fuel pipes.
Stragly enough...after getting worse over the last couple of days....it started first go this morning and this evening!!
I have thrashed the engine a couple of times (no plumes of smoke or anything) but it has made no difference to the 'knock' at all, may be a little worse or more consistant when warm.
It has been mentioned that using a little rape seed oil works wonders!

The belt tensioner is noisey and seems to getting worse now I know what it is! this can make a horrible noise but it is separate to the deisel 'knock'
If thats how they are, then I can live with it, but it just doesnt sound normal to me......
Oh, another thing...there seems to be excessive play in the n/s/r wheel bearing, though there is no noise and the heb nut is torqued correctly......a new one is £70-£90 ......why so expensive?? I dont want to stip it then need a bearing, but also, don't want to buy one and find I don't need it...... would love to see a sectional diagram so I can figure out what is wrong/ worn......

Once again thanks for any input...

 

[MB250TD]

Dear Colywobble
You might like to check out the last post in this thread regarding fuel lines http://www.mbclub.co.uk/forums/showthread.php?t=68028
Having done this job last w/e, I am happy to answer any queries.
Regards
John

 

[Smiley]

The rear wheel bearings is one of the few real PITA jobs on this car. My nsr went at 180k miles . It is worth going to an indi who knows what they are doing - the bearing has to be pressed out of the carrier and it is possible to break the carrier if not done correctly and a new one is several hundred pounds. The bearing is expensive because 1. it is quite big, 2. it has a MB profit mark up rather than a bearing supplier mark up and 3 it comes as a kit with some other fitting components (I think).

I think you just have to live with the diesel knock - mine knocked even more after new injectors were fitted - after 10k miles it quietened down a bit - after 20k ish miles it is pretty quiet again most of the time - I give it some leeway as it has done over 200k now.

 

[Phil Thomas]

The rear wheel bearings is one of the few real PITA jobs on this car. My nsr went at 180k miles . It is worth going to an indi who knows what they are doing - the bearing has to be pressed out of the carrier and it is possible to break the carrier if not done correctly and a new one is several hundred pounds. The bearing is expensive because 1. it is quite big, 2. it has a MB profit mark up rather than a bearing supplier mark up and 3 it comes as a kit with some other fitting components (I think).

I think you just have to live with the diesel knock - mine knocked even more after new injectors were fitted - after 10k miles it quietened down a bit - after 20k ish miles it is pretty quiet again most of the time - I give it some leeway as it has done over 200k now.

If you look at the bearing and find the manufacturer and part number on the bearing you can sometimes buy it direct from the manufacturer or his local agent. I did so once on a Citroen CX and saved one third of the Citroen price. The bearing was even in stock, and nearer than the dealership.

 

[Smiley]

If you look at the bearing and find the manufacturer and part number on the bearing you can sometimes buy it direct from the manufacturer or his local agent. I did so once on a Citroen CX and saved one third of the Citroen price. The bearing was even in stock, and nearer than the dealership.

Thats true and I did think about that - however the MB bearing comes as a kit with some other fitting parts (cant remember exactly what) and I am not sure that they are available separately.

 

[colywoble]

Thanks,

Still not confident about the engine noise, but it seems to drive fine over the last 1000miles since i've owned it.
Got a wheel bearing from EURO CAR PARTS, £30 plus vat!!!!!
Bit of a job to fit, but worth it.
Replaced the gearbox oil......bloody hell, what a difference.....the oil looked like a grey, burnt engine oil!! Fresh oil and filter has transformed the performance, lively, kickdown, smart pull away......cruises at slightly lower rpm.......:bannana: