I think I am correct in thinking that the lines carrying the fuel on the PD engine are heated. Can anyone confirm this, and at which point in the system is the heat applied and how it is done.

Ta

I thought they were cooled - there is a 'radiator' visible if you look underneath the car about where the drivers seat is.

As above

Isn't the cooler for cooling return fuel from the engine?

I don't know of a heater for the fuel on the Octavia, but I have owned diesel cars in the past with a fuel heater built into the fuel filter. AFAIK in my old car the fuel heater only heated the fuel to about 20C or so.

Edited 16 January, 201313 yr by booke23

Hi

One of the things that makes me think the fuel is heated - is because in the summer I played around with a very limited OBD2 software and cheapo lead off ebay. It allowed some very basic parameters to be monitored - one of which was fuel temperature and it was well above ambient. So this makes me think it is heated.

Its of concern of course in winter with low temperatures. Diesel fuel is known to get thicker and even gel, and of course heating the fuel lines would stop this. In countries with very low temperatures (Canada etc) they sell No 1 diesel during winter months, which is thinner and gels at a much lower temperature (similar to paraffin). Our diesel is No 2 diesel.

Yes, it is for cooling the fuel returning to the tank.

Wouldn't surprise me if Scandinavian spec oil burners had some sort of pre heater though.

I didn't have any problems at -17 the other winter though.

The fuel will be above ambient temperature once the engine heats up, since the fuel is constantly circulating and unused fuel is returned to the tank via the return line. Since this fuel has been through the fuel system it gets heated by the engine before being returned to the tank. Some of the heat is removed by s small radiator in the return line in order to reduce the temperature of fuel in the tank.

Wont garages be using 'winter' diesel or doesn't 'white' diesel need this? I know from being in farming that during the colder months you get 'winter' red diesel delivered.

The fuel will be above ambient temperature once the engine heats up, since the fuel is constantly circulating and unused fuel is returned to the tank via the return line. Since this fuel has been through the fuel system it gets heated by the engine before being returned to the tank. Some of the heat is removed by s small radiator in the return line in order to reduce the temperature of fuel in the tank.

What he said plus:

As the fuel is constantly circulated and pressurised that will heat it up and given the scary pressures involved in a PD fuel system potentially quite a lot. My old injection pump tdi didn't need a cooler like my current PD engined Octavia.

Ok thanks for all your replies. What you say makes sense - thanks

If you're concerned you can get a block heater mat and a heater mat that you place around your fuel filter cannister.

You'd run these off the mains before you take your car out, but it would pre heat it all up.