Technical Fuel leak at injector pump - 1.9 JTD 8v

[newportz]

Hello,
I've been tracking a diesel fuel leak for some time and finally managed to see the leak with my own eyes- earlier just lots of fuel pouring from under the car, soaked back of engine or a puddle on the ground. Always searched for the leak and never found it until today - it's just pouring (bubbly fuel) out of the top head. So, of course, replace/regen the pump. The thing is, when I turned the motor off, then right back on, there was no more leak. That's why I've been chasing this leak for about two years now. For example, I've been driving for about 3 months now leak free. I just came back from a 800 km trip with no leaks. I was changing my fuel filter today and when I turned on the car, I noticed the leak.

Does anyone know why the pump would leak, then stop leaking after a restart of the engine? I used to think it was an summer/winter thing with cold weather causing the issue, but we've had pretty stable weather the past month 50-10 degrees at night and 12-15 deg in the day. I also considered an excess pressure issue so I replaced the o ring on the pressure relief valve that attaches to the fuel pump. Anything else that might create/control excess fuel pressure?

Any ideas?
Thanks in advance
Thomas

 

[bugsymike]

Hello,
I've been tracking a diesel fuel leak for some time and finally managed to see the leak with my own eyes- earlier just lots of fuel pouring from under the car, soaked back of engine or a puddle on the ground. Always searched for the leak and never found it until today - it's just pouring (bubbly fuel) out of the top head. So, of course, replace/regen the pump. The thing is, when I turned the motor off, then right back on, there was no more leak. That's why I've been chasing this leak for about two years now. For example, I've been driving for about 3 months now leak free. I just came back from a 800 km trip with no leaks. I was changing my fuel filter today and when I turned on the car, I noticed the leak.

Does anyone know why the pump would leak, then stop leaking after a restart of the engine? I used to think it was an summer/winter thing with cold weather causing the issue, but we've had pretty stable weather the past month 50-10 degrees at night and 12-15 deg in the day. I also considered an excess pressure issue so I replaced the o ring on the pressure relief valve that attaches to the fuel pump. Anything else that might create/control excess fuel pressure?

Any ideas?
Thanks in advance
Thomas

If a union or sensor had been overtightened it could have cracked the casing.
I would dry it throughly, then start for a few seconds and get a tissue paper to check were leak coming from.
Don't forget, with Common Rail diesels the pump pressure is very high and a fine mist from it can easily penetrate your skin needing serious hospital treatment.

 

[newportz]

Thanks for the reply, definitaly have given it consideration. My question is more directed to how the pump could leak - fuel coming out between top head and housing - then just stop leaking. What's up with that?

Any cracks in the pump would leak regularly. In my case it's unpredictable, or at least I haven't found the predictor.

 

[bugsymike]

Thanks for the reply, definitaly have given it consideration. My question is more directed to how the pump could leak - fuel coming out between top head and housing - then just stop leaking. What's up with that?

Any cracks in the pump would leak regularly. In my case it's unpredictable, or at least I haven't found the predictor.

Can be temperature related and remember we are dealing with 1000s of pounds of pressure.