Removing deposits from burner element (only when running on vegetable oil methyl ester) — AUDI

Notes:

Problems may be encountered with additional heater operation in cold weather in vehicles with diesel engines if vegetable-oil methyl ester is the main fuel that is used.
Reason:
Because of the physical properties thereof, deposits may form on the evaporation fabric in the burner element. These deposits could affect combustion if vegetable-oil methyl ester fuel is used for long periods.
These deposits can be broken up and therefore removed by the petrol combustion process.
If evaporation fabric in burner element is so clogged that no flame can be produced, replace burner element => Page
82-60

Preconditions:

If the fault memory was interrogated =>Page
01-24
and any displayed faults rectified.
Initial coolant temperature less than 30 °C.

Removing deposits:

Switch ignition off.
Remove the cover under the fuel filter.

=> Relevant Workshop Manual, Fuel System

Detach the fuel line -A- from the metering pump and close it off with the closure plug -B-.
Pour approx. 1 litre of fuel (petrol) into container -D-.

Notes:

Container -D- must contain an ascending pipe that reaches the bottom of the container.
There must be an opening in the container lid to prevent a vacuum from forming when fuel is removed.

Attach container -D- (VAS 5086) to the vehicle near the metering pump.
Squeeze container -D- until fuel reaches end of hose -C-, then attach hose to metering pump.
Start the engine.
On the heater controls or the -E87 operating and display unit set the system to maximum heating output (e.g. temperature preselection to "Hi" of temperature rotary knob to "Warm" stop and blower to stage 4).
Open all windows.
Initiate self-diagnosis for the additional heater and switch on the additional heater via the function "Basic setting" => Page
01-49
Repeat this procedure 3 times (the additional heater must be run with petrol for at least 30 minutes).

Notes:

As the operating time of the additional heater is limited to a maximum of 8 minutes via the function "Basic setting display group 22" this function must be performed 4 times in total. For this the additional heater must be first switched on via the function "Basic setting display group 33" and then off again via the function "Basic setting display group 22" after completion of cut-in time and the end of the caster time.
The additional heater can be operated via the function "Basic setting display group 22" up to a coolant temperature of 115 °C. Starting from control interval is possible.