Yo,

Does anyone know what the weird Radiator/heatsink thing is for under the car, right under the drivers seat?

Cheers!

Its a fuel cooler.

Thanks!

For the diesel? How does that get hot?

Or is it cooling the derv straight from the fuel tank before it hits the engine? And why?

Cheers man.

More the other way round, it cools the fuel returning to the tank to ensure it does not melt the tank IIRC

The injectors run and internal pressure of 2050 bar. this has a habit of heating the diesel up. Fabia has a plastic fuel tank, dumping that fuel back in at that temp would melt the tank so a cooler is fitted ont he return line.

Brill - mucho thanko for the info

Its cooled on the way back to the tank to stop condensation build up in the tank , which ends up as moisture in the fuel,the fuel in reality doesn't get that hot as to melt plastic , most diesel's have plastic pipes direct from the engine direct from injectors.