Fuel shutoff valve - small bubbles after revving - PeachParts Mercedes-Benz Forum

m1tch · #1 06-13-2015, 01:14 PM

Hi all,

My E300 turbodiesel is running much better now that I have been running some 2 stroke oil in the tank plus a bit of an 'italian tune up'. Ever since I have had the car I have noticed a few bubbles every now and then after the engine is revved slightly on idle (noticed this when I was checking for boost leaks).

All of the fuel lines apart from 1 are bubble free, I have found that the line on the side of the pump has a few small bubbles after revving. It seems to be the line on the fuel shut off valve, its on the right hand side so I think its a return line?

Am I correct that that there could be a few bubbles on this line as I believe it is a return line meaning that after the engine revs it has used a tiny bit of fuel.

I believe that all of these lines have been replaced fairly recently as they are all clear in colour, the fuel shut off valve on the side does look slightly damp, but its near to the air intake temp sensor which I know has leaked.

Just wondering if it should be something I should be worried about or if its normal?

jay_bob · #2 06-13-2015, 03:31 PM

There is an o-ring behind the shut off valve and one in the pre filter that can cause this problem.

m1tch · #3 06-13-2015, 04:25 PM

Quote:

Originally Posted by jay_bob

There is an o-ring behind the shut off valve and one in the pre filter that can cause this problem.

I will have a look at swapping those out, I am planning to take off the inlet manifold for cleaning at some point so I will look to change things on the pump at that point.

It doesn't seem to affect the idle or running of the car so I am thinking that it might only be perhaps the start of it leaking air - something to keep an eye on anyway.