320 CDi with a major diesel leak!

[Mercsys]

Hi all,

my 210 320 CDi has sprung a major diesel leak to the lower left (turbo side) of the HP pump, it has has a new set of return hoses some 6 months ago so I don't think it is them, it is not a drip but a continuous stream once the engine is running.

Any ideas or pointers before I begin?


ty

J

 

[Mercsys]

... is there such a thing as an input shaft vent to stop a shaft seal leak dumping diesel to the crankcase? Or is this taken care of by the return hoses?
It's not the return hoses but looks like from around the lower pump head, but the flow is huge, and a head I would have thought would have sprayed out! Where does the lift pump enter the HP pump?

Anyone seen a HP pump head O ring leaking?

Next, fan off to see where the leak is when she is running!

J

 

[walsi]

Hi ya, might be a stupid suggestion but when you said its a stream the first thing that i thought of was a split diesel return line either on the line or on the injectors and it just appears to be coming form the pump. If the pump was leaking like that i would expect the engine to stop and the edc light to be on

Martin

 

[Mercsys]

..not impossible, but they are new, it starts as usual. I just cant see what is going on!!

 

[walsi]

I would say it must be on the return line somewhere if it is leaking when the engine is going and is still starting and running ok, anywhere else would cause air ingress into the system and stop the engine. It might even be one come off at an injector, it does happen sometimes and just be running along the rocker cover so it appears the pump is leaking

 

[Mercsys]

...it looks like it has blown out the secondary seal on the HP pump to the valve body along side, this would mean that the primary seal O ring is shot. The access is not too bad once the fan cowl and fan have been removed.

 

[Mercsys]

Done.
I should have replaced this O ring when doing the return lines, If they were shot this one was also.