ML 270 CDI expansion tank hoses

Andy McMullan

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Hi Everyone

I took the expansion tank off to do the injector seals and on refitting, checked the upper and lower hoses on the nearside of the tank against the parts diagram to make sure I had put the hoses on correctly and not mixed them up.

I have the lower one connected to the top of the radiator, hopefully Part 80 in the diagram. In the picture I've pulled it up and to the right and you can see a plastic valve with a direction arrow on it pointing towards the expansion tank.

The top one is supposed to be part 50 in the diagram.

This part 50 looks nothing like the hose on my car which in the photo is running beside the EGR valve and into a small metal pipe on the engine. There is no branch off the hose as per the diagram.

Maybe this hose has been replaced by a previous owner?

Could I get some advice on these hoses please? Do they look ok?

Cheers, Andy

20200820_202148.jpg
20200820_200012.jpg
 

joderest

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nice clean engine !!!!
Anyway, I will have to have a peak under the bonnet of mine, but its at home and i am at work. From what i have seen on line, the top hose should be clipped into the built in retainer on the tank and go down behind the accumulator. I suspect that being off the top of the tank its some sort of return pipe.
 
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Andy McMullan

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nice clean engine !!!!
Anyway, I will have to have a peak under the bonnet of mine, but its at home and i am at work. From what i have seen on line, the top hose should be clipped into the built in retainer on the tank and go down behind the accumulator. I suspect that being off the top of the tank its some sort of return pipe.

That's brilliant. Thanks for helping out.
 

joderest

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Further, found a picture on line that states this pipe is......
Vent, engine cooling system and cabin heating. I wonder if the diagram you have is for something other than uk, and the car has something extra that a uk vehicle does not have, hence the spliced pipe ?
It appears you have hoses correct way round.
I will have a peak under the bonnet of mine tonight if i remember.
 

joderest

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Ok, you need to check, just got home and looked at mine.
Bottom hose runs from expansion tank to front of engine where it joins a metal pipe which could go to thermostat, not sure.
Top hose goes from expansion tank to side of radiator.

There is not any extra pipe in any of the two pipes, I would suggest the diagram is for petrol powered vehicles in another country.

You need to check as looks like you have them incorrect way round. DO NOT take my word for it as I maybe incorrect, but that is how mine runs.
 
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Andy McMullan

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Thanks for checking. It sounds like I have mixed them up. I put my VIN into the 7 Zap site and got info back for the 270 CDI. Maybe it is the wrong diagram?

I'll keep checking for images on the web.

Cheers
 

joderest

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All I can say is the pipes on mine are same as yours, no tee piece.
I really would check carefully you have pipes fitted correctly, as could cause you an issue.
I am surprised no one else has chirped up yet.
 
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Andy McMullan

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I case anyone else has a look, for clarity I've put some pieces of masking tape on the hose that I've got attached to the top of the expansion tank. The hose attached to the lower fitting on the expansion tank and the radiator is resting on the fuse box. Cheers
20200821_155012.jpg
 

joderest

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Hi.
Just checked again and that pipe runs from bottom of expansion tank to pipe at front of engine, the pipe from top of expansion tank runs to radiator.
That's how my 2003 ,ML270 is and pipes have never been disturbed, I am second owner.

But please. Confirm this for your selve.
 
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Andy McMullan

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If yours is running well with that set up, It's odds on it's correct and my hoses are mixed up.

I really appreciate you checking that for me. Cheers, Andy
 

Taffy7hfa

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Hi, it’s hard to work out from a photo as the pipes may just be routed differently, if it’s working ok I wouldn’t worry , just out of interest what are the zip ties for at the top of your injectors ? CDA205F9-1825-47E2-A4F3-E967557D753C.jpeg
 
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Andy McMullan

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Hi, the injector multi plugs have the tabs broken off so arent clicking home properly. The zip ties are holing them on. Once i get the injectors sealed properly I'll sort that out.
Cheers
 

Taffy7hfa

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Brilliant :), how many miles on your ML ?
 
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Andy McMullan

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There is 123K on it.

I bought it with a few issues for £950 a few weeks ago. I didn't realise it was leaking diesel which was picked up on the MOT.
I'm currently working through that issue with the injectors and will then tackle the rest.

I had another look at the expansion tank pipes and the bracket that the 2 pipes go though before connecting to the tank seems to suggest where they should locate on the tank. Your ones are that way as well. Thanks for posting your photo.

Here's a picture of the bracket with my hoses now changed to the correct routing. Cheers 20200822_193653.jpg
 

Taffy7hfa

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Just about run in then ;)
 


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