Fuel leaking onto belt

[MrHax]

I recently bought a 2003 ML270 with 156k on the clock, it has been okay so far but after a few days, I started to notice small amounts of smoke coming up from the front when sitting in traffic, especially at night in the headlight beams. Then one of my colleagues bought my attention to a small puddle beneath the car when I finished work one day. I dipped my finger in it and smelt diesel and it was relatively clear on my finger. Having removed the engine cover, I have noticed that there is small bit of wear on the pipe beneath what I presume to be the fuel pump where it is at its closest to the belt and a very small drip coming off of it. Also I quickly checked the injectors and noticed the base of numbers 1 and 3 are a little bit wet. So I have taken the liberty of ordering 5 new seals and bolts as a precaution as I have heard the bolts expand over time on these so worth doing at the least if anything.

 

[Blobcat]

Injectors leaking on ML270's is quite common unfortunately. I've known some where they've used a helicoil on the injectors when the threads failed.
This isn't the best idea as the pressures are immense. I know one that popped out on the M4 and it went up in flames...

 

[alexanderfoti]

High pressure pumps do leak, and when they do , straight onto the belt

also the low pressure pump on the front sometimes leaks, it can be the small pipe that links them that fails.

The head sealing faces need to be shiny metal clean for when you reinstall the injectors, bolts are 7nm + 90degrees + 90 Degrees

 

[MrHax]

Thanks guys for the advice, does anybody know the specifics of the tube I need to replace, its the one that goes from the L/H side of the pump, underneath it and back up over the head parallel to the fuel rail to the back of the engine bay. I would say its about 2/3 of a metre in length.

 

[alexanderfoti]

If its the clear plastic one, just buy from MB, or even better, replace the o rings on the end.