Thermo Top C Installation: Audi A6 4B 2.5 TDI

Hello,

I want to retrofit a Webasto Thermo Top C auxiliary heater into my Audi A6 Avant 2.5 TDI, manufactured in 2000. I have most of the parts needed, except for the one for the fuel connection.

I have a vehicle-specific installation manual for the Thermo Top T. However, it has its own tank, and the fuel is drawn from the front near the filter. Unfortunately, this doesn't work with the Thermo Top C, which is why I'm now unsure how to do it and which parts from the Webasto range I need (fuel tank sender, fuel pickup...). There are quite a few different options available. I have already contacted Webasto, but they haven't tested my car with the Thermo Top C and can't provide any information about it.

Has anyone here done something like this before and can help me?

I think, apart from the fuel consumption, the instructions for the Thermo Top T should be applicable, right?

Regards,
jugi

Does your auxiliary heater have a separate dosing pump, or is everything integrated into a single unit?

Does your auxiliary heater have a separate dosing pump, or is everything integrated into a single housing?

The dosing pump is separate. I already have one of those.

Regards,
jugi

Hi,
To be on the safe side, you should install a fuel pickup, which I mean a suction pipe, into the cap of the fuel tank sender. It can even be an Eberspächer part if it's more readily available. The dosing pump should then be mounted as close to the tank as possible. However, this is more expensive than a T-piece, which is often used for this purpose (costing around 50 DM back then). But in your car, I would definitely avoid using the main fuel line due to the pre-pump, and you should at least check beforehand whether the return line ends low enough in the tank.

Hi,
To be on the safe side, you should install a tank pickup, which I mean a suction pipe, into the cap of the tank sensor. It can also be an Eberspächer product if it's more readily available. The dosing pump should then be mounted as close to the tank as possible. However, this is more expensive than a T-piece, which is often used for this purpose (costing around 50 DM back then). But for your car, I would definitely avoid using the supply line due to the pre-pump, and whether the return line ends low enough in the tank should be clarified beforehand.

My problem is that there are many different fuel tank senders in the Webasto range. I'm not really sure which one I should choose. I think I'll have to ask Bosch's service department.

What do you mean by 'feedback'?

Basically, a tank filler is nothing more than a fitting that is installed in the tank nozzle, right?

Regards,
jugi

jugi wrote:

What do you mean by "feedback"?

If the return line doesn't reach below the diesel level in the tank, the auxiliary heater simply sucks the return line dry and then draws air from the tank. To get it working again, it then needs to be bled. }

/Jan

jugi wrote:

My problem is that there are countless different fuel tank sensors in the Webasto product range. Basically, a tank filler is nothing more than a fitting that is installed in the tank nozzle, right?

At Webasto, T-pieces that are installed in the supply or return lines are also referred to as "take-offs."
It's probably best to get advice. Basically, you just need to specify the desired inner diameter of the nozzle and the length of the suction tube.

What do you mean by 'feedback'?



If the return line doesn't reach below the diesel level in the tank, the auxiliary heater simply sucks the return line dry and then draws air from the tank. To get it working again, it then needs to be bled.

/Jan}

That only happens if you tap into the return line, right? If you use a tank pickup, it doesn't matter.

Regards,
jugi