Ml 270cdi - 2004

[davr]

Hi

I am told my ML intermittent/poor starting (if ML left 24 hours - fine otherwise) is due to degraded O rings from filter forward on white plastic fuel lines. I am told air is likely leaking in past the O rings. Starts and runs OK if I squirt some brake/clutch cleaner into air filter for first start of the day. Are the O rings easy to replace? Will I "see" what to do with the engine cover off? Any tips please? Any special tools needed?

Many thanks

David

 

[MOZ]

Sounds like the probable cause, you may find the plastic clips in the ends of the pipes have become brittle and cracked/snapped too so may need to replace the plastic fuel pipe ( around £35 ish each there are 3) I have changed 2 of mine.

Changing o rings is ok ( about fiddly in places - round the left side of the engine under the high pressure fuel pump).

Just take your time and be careful ( don't be tempted to prize the black plastic male connectors out with a screwdriver as the plastic is brittle and is likely to crack meaning the need for a full new pipe), just take your time and wiggle them out by hand.

Once the male parts are out changing the 0 ringis very easy.

The two pipes going into the bottom of the High pressure pump are the worst ( tight space) you will need a small ratchet with ideally a female Torqx socket ( can't remember what size but you can use a standard hex socket 8mm or 10mm ish) there is 1bolt holding a clamping plate which pushes the 2 pipe connections into the HP pump ( front left of the engine just behind the aux belt). Once the metal plate is off just pull the pipes out ( careful as everything may be brittle and crack ), change the o rings and put it all back. All the other ends should be clip on male ends (with little white or yellow clip openers ( different types push in to release the clip and others are pull out to release- just take your time and work out if it's a push in or pull out type) as I say these clips get brittle and may break, but straight forward ( the one into my fuel filter was broken and needed replacing as it was letting air in).

Changing the pipes if you need to is easy.

Tip if you need to replace the pipes going under the HP fuel pump near the aux belt get some spare pipe retaining clips that hold the pipe to the front of the engine as they break when you take the old pipe off.

See this thread for some more info

http://mbworld.org/forums/m-class-w163/565417-ml270-diesel-unidentified-t-bleed-contraption.html

And

http://www.mbclub.co.uk/forums/engine/185374-w163-ml270-thermostat-replacement-broken-fuel-line.html

This subject comes up a lot and is very common in the 270cdi so do some searching and I'm sure more tips will be found.

Hope this helps.
Good luck
Moz

 

[davr]

Thank you Moz.

Many thanks for your reply Moz. I will give it a try.

 

[colinp]

I changed all 3 pipes on mine bit tight on the front of the engine at the pump end worth replacing the clips that hold them they will break when you pull the pipes off.

 

[W210Virgin]

Don't waste your time with O rings. Just replace the pipes as they come complete. Remove the brake vacuum thingy at the front left and it will give you good access under the HP pump.