A6 C6 2.7 tdi fuel leak at High Pressure pump

[KristoffV6]

Gave the car a full detail today and noticed a small pool of fluid on the floor under the engine bay when I moved the car back into its normal space. The fuel was clearly diesel.



I whipped the engine cover off and the area around the high pressure fuel pump had standing fuel present in bolt holes etc.. so I knew something was wrong, there is clearly a leak somewhere. Went to star the car again...... and it wont start, it just turns over. When turning over fuel is clearly leaking from the high pressure fixing circled in the image below.



It's not squirting out at high pressure, but it's definitely leaking out of that pipe fixing. I took the fixing off and cleaned it up and re-tightened it. No difference, car still won't start and fuel is still leaking from there.



Any idea what the problem is? Do these high pressure fixings wear? Seems unlikely to me. Would too much pressure in the system cause a leak at that point? Has there been some failure of the fuel pump do we think?



I'm at a bit of a loss and I've got a bit of a problem as I can't getting down my steep drive to take it to be looked at if it won't start.

 

[B5NUT]

I would look at removing the pipe and cleaning up the joints, corrosion can take place so clean the nipple area with a bit of wire wool & refit.

Like shown in this image.

 

[KristoffV6]

That was my first thought as well. I took the pipe off and the fitting looks fine, no sign of corrosion like in that picture.


Do you think there is any chance that some sort of return might be blocked? I was thinking that might cause an issue with fuel being forced out of that fixing in the picture. Although if that was the case the engine should still have fuel so should still run I would have thought, just have a leak whilst its running. Seems strange that I have fuel coming out of that pipe fixing, which must mean that the HP fuel pump is working, but it won't start.

 

[B5NUT]

Could not say, are you sure the fuel is coming out of that joint? If it's leaking lots of fuel then the pressure may not be correct so the engine won't start (guess) get VCDS on the engine to see if there are any fault codes. If it continues to leak out of that pipe then the only option would be to replace the pipe, and hope the pipe is at fault and not the pump side.

 

[KristoffV6]

All sorted, new HP fuel pipe fixed it right away. Happy days.