Whilst I had my head under the car today (as one so often does with a new car...Elegance estate 1.9 TDi ) I came across something rather odd fixed in the area below the drivers seat. It appears to be a small radiator made from cast alloy with fins.

Can anybody out there tell me what it's for ?

Richard

It's a fuel cooler.

Thanks for your reply...I wondered if it might be to cool the fuel....but is it being cooled before it goes to the engine...or returned to the tank ?

Richard

The fuel filter uses radiator coolant to warm the fuel up, if necessary. The cooler under the seat removes heat from the surplus fuel being returned to the tank having been through the cylinder head (and hence heated).

The high pressure in the fuel system creates high temps. Returning said fuel would melt the plastic tank so its cooled down first.

Fuel isnt warmed up as such, but there is a valve in the top of the filter (the t piece) this feeds the returned fuel back into the fuel filter, as this is warm it prevents waxing of the fuel when cold. The valve only operates for a very short time when very cold.