Part # for '05 e320 cdi, fuel return line
 

Can anyone give me the part # for the fuel return line on an 2005 e320 cdi? I believe MB makes it as one assemble with the hos, "L"s and "T"s connectors.

I am thinking replacing the entire assemble makes more sense then replacing just the lines given the chance of plastic "T"s cracking and o-rings failing.

Found it.....

Part #: 648-070-08-32
Bosch 0-928-402-047

Any thoughts on replacing it? Car is 14 yo and has 140k miles.

I know on the 642 it is a complete assembly, with all the fittings, and that is the only way you can get it. I suspect it is similar on the 648.

You are right, the chances of the plastic pieces surviving a change of hose probably isn't going to happen. In fact you will be lucky if you can remove the old assembly intact without breaking anything.

When I did a image.google search for hose 648-070-08-32 in some of the pictures that came up there appeared to be some places in the UK that sold fuel return lines with brass instead of plastic fittings.

Some of the makers names: maXgear and maybe Beat Doria

This company makes Hose with Aluminum fittings instead of plactic
Item Name: Hose Fuel Overflow

Part Brand: Metzger

OEM Numbers: 6120700932 / 612 070 09 32 / 6120701032 / 612 070 10 32 / 6120703832 / 612 070 38 32 / 6120703932 / 612 070 39 32 / A6120700932 / A 612 070 09 32 / A6120701032 / A 612 070 10 32 / A6120703832 / A 612 070 38 32 / A6120703932 / A 612 070 39 32

Housing material: Aluminium
Fuel Mixture Formation: Common Rail (CR)

Thanks for info.

I also found "Metzger" on eBay with shipping from Latvia for about $55.59:

Metzger CDI Fuel Return, OM648, E320 CDI

Sounds like it is a good idea to change this line out before it fails on a long trip somewhere.

I heard from my mechanic that the return lines fail from age on the old W123s and W124s. Same on W211? Any firsthand experience(s)?

There is a store on ebay that has the fittings, and they come from the USA. They are for a Sprinter. I ordered a set for my CDI, and just used regular return hose. It was WAY cheaper doing it this way, than getting the entire assembly from the Stealership.

Is it easy to disconnect the fittings from the injectors?

$55 all in for the complete replacement part doesn't seem bad. How much were the fittings and hose by themselves?

Assuming the 648 injectors work like 642s:
Grasp the fitting and pull gently but firmly. Be sure to keep the force along the axis of the fitting. You think you’re going to break it but it is just held by friction.

The fittings look like they are held in place with spring springs in the shape of bobby pins.

Yes, just pull out the clip, and the fitting just pulls straight up out of the injector. The fittings from the ebay store were only about $15. I just had them on hand when one broke. My family has 3 W211 Diesels, so having them in stock is a good thing. Of course I have the return line in stock for the 617's.
By the way, today is 6,17(19)

Ah I see, there is no clip on the 642 return ‘leak oil’ fittings, so they must have changed the design.

Thanks for info. I went ahead and ordered the entire replacement line.

A friend of mine who works at Bosch (since 1968!) recommends replacing the entire part:

"Replace the assembly – same labor and effort instead going back and replacing the fittings at a later date."

Given these vehicles are now almost 15 years old and past history of return lines leaking/failing on the W123 and W124s, it probably is prudent to do this as preventative maintenance.

I am not saying you should not replace all the fittings and the hose, but that the parts separately are a lot less expensive, and better. The factory hose assembly may have plastic fittings, whereas the aftermarket are chrome plated brass (the ones I got). At the time I only had 4 of them, so I only replaced the one I broke plus the hose. If I had all 6 fittings at the time, I would probably have replaced all of them. There are 3 CDI's that I take care of, so it is good that I have these parts in stock.

I get it and agree the lines and fittings should be replaced. Either via buying parts separately or as one part.

I just thought at $55 shipped, the entire assembly with aluminum fittings was a good price:

Metzger CDI Fuel Return, OM648, E320 CDI

I'd consider this one of the PMs our 2005-6 CDI's should have done given the age and mileage of these vehicles. The switch over to to low sulfur fuel early in their lives and the multiple heat cycles under the engine cover play havoc on the rubber fuel lines.