After running over a load securing strap and buckle I have damaged/smashed the plastic undertray on the drivers side. This is not the engine undertraybut the one that runs along the side by the doors. I have also noticed some severe scuffing/denting to a finned oblong aluminium block.

Can someone tell me what the aluminium block is and does anyone know what a new undertray will cost?

AIRC it's an in-line fuel cooler.

Yes that's right, it cools the fuel in the return line back to the tank from the injectors. I've dented mine too after running over a branch.

I'm no expert, but as long as it looks like it gets air around the fins, isn't leaking and is secure I wouldn't worry too much.

Les.

Yup, mine has taken several whacks from FOD in various shapes and sizes, still seems to cool OK though.

OK, I'm not proud, I'm going to go ahead and ask something I've been wondering about. Can somebody explain the fuel return line to me?

OK, I'm not proud, I'm going to go ahead and ask something I've been wondering about. Can somebody explain the fuel return line to me?

The idea is you pumpt fuel from the tank at at least as fast a rate as required for full power, then whatever isn't actually used gets returned to the tank. It ensures there's always enough fuel and helps keep it cool.

There is a flow pipe from the tank to the filter body in the engine and a return from the engine to the fuel tank. The pumping/fuel injection process (especially PD units) warms the fuel considerably, the ally fuel cooler obviously acts as a good heat sink to remove excess heat on the way back to the tank, no one wants hot fuel in their cars now do they

As I understand it, the Pumpe Duse injectors use a cam-driven piston to compress a fixed quantity of fuel, and solenoid valves to control the actual quantity injected. Any excess pressurised fuel is returned via the return line. As the previous poster, passing through the tandem fuel pump and injectors heats the fuel enough that it has to be cooled before returning to the tank.