Diesel in the Cooling System - How???

[Rags]

Hi all, I'm new here.

I have a problem with my 1.9 TDI - it appears that diesel is somehow getting into the cooling system.

I have heard of engines losing coolant, but mine is gaining fluid! I have so far removed around 2L of what appears to be diesel from the Coolant Expansion Tank. Assuming it is diesel - how is this possible? I would have thought that the fuel delivery system would have been totally separate from the cooling system.

From reading various sources on the web I'm starting to wonder if it is something to do with the tandem pump as this might possibly be where water meets fuel. Is it possible that a gasket failure (or similar) could result in fuel getting into the coolant?

Can anyone please enlighten me?

Otherwise the engine is running smoothly, the temperature is stable and the engine uses no oil. I also haven't noticed a higher than usual fuel consumption.

Thanks in advance.