Leaking diesel 270 CDI

[Matt_ML]

Hi, I have an ML 270 CDI 2001.

I've noticed for some time now that after a run there is a smell of diesel fumes and if left over night always leaves a puddle around where the sub frame is.

So today I decided to investigate and I have found a pipe.. hanging pointing downwards and its coming out of that!! i touched what was coming out with my finger and its the exact same smell as whats on my drive. So does anyone know what this pipe is??! It goes up the back of the engine and goes in to what looks like the head of the engine.. or in that general direction anyway (Can't fully see tbh!)

 

[Ellsy Tanners]

That sounds to me like the drain off pipe fitted to the back off the cam cover well. This is there to drain off any diesel that leaks from the injectors them selves or the leak off pipes along the top. take off the engine cover and take a look there.

 

[Matt_ML]

Thanks for the reply... I can't seem to see a photo of any hoses in that link.. its just covers by the look of it? Does it sound like it could be an expensive problem? I'm popping to the dealers in the morning to buy a new idler pulley as for some reason my engine doesn't have one and it chirping!

 

[Ellsy Tanners]

Sorry i cant seem to shake off a link i used earlier.

No it shouldnt be to expensive, something may need tightening of the leak off pipes on top off injectors.

 

[Matt_ML]

Ohhhh so its not the injectors themselves then? just a perished or split pipe etc? I'll be really glad to get this problem sorted, it often smells the inside of the car if i put the fans on!!

Do you know of any reason why my 270 hasn't got an idler pulley? I'm guessing it should have and someone has removed it for some reason!

Thanks again in advance

 

[Ellsy Tanners]

It doesnt sound like the injectors themselves as it is diesel that is leaking. taking the engine cover off is the only way to tell.

If you didnt have a idler pulley then it would be inmpossible for the belt to fit the car. What is the problem you have, it cant just be missing!

 

[Matt_ML]

That pulley that I am pointing to, is missing on my engine! there is just a threaded hole where it looks like it should be.. and the tensioner is at its full extension!

 

[Matt_ML]

dam! yeah thats exactly what i have at the moment. I thought I'd solved it there as well!

so the pulley that is making the chirping noise is the darker one just to the left of the two on the right, is that what you call the tensioner pulley? Do you think thats easy to swap!? I'm just trying to work out where the idler pulley is!

 

[Ellsy Tanners]

That would be unusual for the pulley to come off, ive just had a look and some pictures show it and others dont so your engine may not have it. If it had fallen off then the belt must be very slack

 

[Matt_ML]

well I could only assume the tensioner would compensate. but obviously not enough as its chirping away! erm, i'm just wondering if it could just be my tensioner thats gone.. (It was very still when i levered it to one side, and made a creeking noise etc!)

 

[Ellsy Tanners]

Go to your mb parts dealer and see what they say for your exact chassis number, it could just be a whining pulley. they are easy to swap, the cover in the middle pops off and there is a trox bolt holding it on.

I deleted the last post with the link because there was another pic with the set up on the picture in your post so i didnt want to tell you something that wasnt 100%

However i wouldnt be supprise if your engine doesnt have it.

Is your belt slack as it is, of rubbing on the water pump pulley?

 

[Ellsy Tanners]

Do a search on here for alternator free wheel clutchs, they are the alternator pulley and can give problems like you discribe,

 

[Matt_ML]

I'll do that in the morning then, I'm assuming the diesel leak won't be toooo bad to drive (mind ive been using it for the last few weeks!)

Its not slack as such.. but it feels as if it could be tighter. Perhaps the belt has stretched as it looks old-ish. I really appreciate this help by the way. Its great

I'll keep you posted on the outcome once I have had the chassis number checked.

 

[Ellsy Tanners]

No problem mate, it a shame because within 30 seconds of looking at your car i would be able to tell you exactly whats wrong!!!

 

[Matt_ML]

Well, my chassis number has brought up that it needs an idler pulley! so have ordered that and the bolt that attaches it to the car!

Upon taking the cover off.... wow, spells really strong of diesel. Injectors appear to be leaking, there's puddles in all the trays. Looking at it with the engine running I can see bubbling coming out of the base of the injectors. Now the parts dpt said this is a common fault and is the copper rings. So I have ordered a set of them. Does this sound right?!

There's also another pipe leaking diesel.. just to the right, with a white cap on the end.. does this look normal to you!?..

 

[stumo]

Now the parts dpt said this is a common fault and is the copper rings. So I have ordered a set of them. Does this sound right?!

You also need new injector clamp bolts, because I have been told they are a stretch bolt design - just like head bolts. You also may or may not need new injector clamps, I'm awiting a response on that since it turns out I have the same problem as you (on the same vehicle too!) see here...http://forums.mercedesclub.org.uk/showthread.php?t=41654

There's also another pipe leaking diesel.. just to the right, with a white cap on the end.. does this look normal to you!?..

Yeah I don't know what that thing is, but on mine it looks like it has been replaced recently as it is a much whiter colour than yours, and I don't think it should be leaking. Yours also has cable ties holding the injector electrical connections on for some reason, it shouldn't need them unles someone has broken the plugs maybe?

 

[Matt_ML]

So I guess I need to ring the dealer and ask if they have the correct bolts too then? I wonder what this other pipe does?! it just appears to be blocked off. Strange!

 

[Matt_ML]

So I guess I need to ring the dealer and ask if they have the correct bolts too then? I wonder what this other pipe does?! it just appears to be blocked off. Strange!

 

[Ellsy Tanners]

Hi again matt.

Is there clean diesel in the wells or is it black gunge?

By the looks of the picture you have posted, your engine has allready suffered for a serious case of black death. This is when the rocker cover fills up with thick black carbon. I can tell this by the general condition and by the main injector wires are bear which is a sign that they have got very hot as a result of black death!!

It looks to of been cleaned up quite well but you can never totally clean it up unless you replace the rocker cover etc.

The reason i ask if its clean diesel in the wells is because an injector base leak is normally a black carbon substance coming up not clean diesel.

If it is clean diesel then something up top of the injectors is the cause. You need to totally dry it out with rags then run and look at it so you can find the source of the leak.

The white bit on the end of that pipe is a test valve connection and unfortunatly must be replaced when leaking. It only comes on a length of pipe which runs under the main high pressure pump.

 

[Matt_ML]

Thanks to you and a very helpful Mercedes technician I have got to the bottom of this!

Its clean diesel filling the wells. This is coming from one of the pipes connecting to the No.1 injector.

There is also leaking from No. 1 & 2 injector seal and you're right the pipe is leaking so I have ordered a new complete section (He also explained to me that the pipe goes around the front of the engine and under the fan belt, so its a good idea to do it all at the same time!)

I can't believe what damage this does when it fails! Its all coming together now though. When I bought the car the pass side headlight was 'tinted' and all sooty! but seeing the amount of carbon which must have been under the plastic cover is incredible!

Hi again matt.

Is there clean diesel in the wells or is it black gunge?

By the looks of the picture you have posted, your engine has allready suffered for a serious case of black death. This is when the rocker cover fills up with thick black carbon. I can tell this by the general condition and by the main injector wires are bear which is a sign that they have got very hot as a result of black death!!

It looks to of been cleaned up quite well but you can never totally clean it up unless you replace the rocker cover etc.

The reason i ask if its clean diesel in the wells is because an injector base leak is normally a black carbon substance coming up not clean diesel.

If it is clean diesel then something up top of the injectors is the cause. You need to totally dry it out with rags then run and look at it so you can find the source of the leak.

The white bit on the end of that pipe is a test valve connection and unfortunatly must be replaced when leaking. It only comes on a length of pipe which runs under the main high pressure pump.