| The fuel for the auxiliary heater is drawn in from the fuel tank by way of the connection -A-, the corrugated pipe -B- and the riser -C-. |
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| In Model Year 2002, the fuel delivery unit for vehicles with 2.5 l diesel engine was gradually converted to the same version as for the other front-wheel drive vehicles (supported on bottom). → Fuel supply system; Rep. Gr.20 and → Parts List |
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| On vehicles manufactured up to 01.03, the riser -C- for the auxiliary heater fuel supply is attached to the fuel delivery unit. However, as no liquid fuel is left at this point on braking or accelerating with the fuel tank less than 1/4 full, only fuel vapours are drawn in by the metering pump -V54-, thus resulting in combustion problems in the auxiliary heater and the emergence of intense smoke from the auxiliary heater exhaust pipe. As of 01.03 modifications were therefore made to the intake pipe for the fuel supply → Chapter. |
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| If the riser -C- is attached to that part of the fuel delivery unit which rests on the bottom of the fuel tank, this ensures that the auxiliary heater can still be operated even if the fuel tank is virtually empty with the vehicle standing on the flat. If on the other hand the vehicle is moving and the fuel tank is less than 1/4 full, sloshing of the fuel can cause problems in auxiliary/supplementary heating mode. The fuel diversion system was therefore gradually converted as of 01.03. |
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| To stop any deposits on the bottom of the fuel tank being drawn in by the auxiliary heater metering pump -V54-, the riser -C- ends approx. 20 mm above the bottom of the tank (dimension -X-). |
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| On vehicles with a riser -C- attached to the fuel delivery unit, the fuel diversion system can be converted by replacing the fuel delivery unit → Chapter and → Parts List |
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| Check operation of the auxiliay heater on completion of work on the fuel system or following replacement of the fuel delivery unit (allow the auxiliary heater to run for at least 10 minutes in full load operation to completely re-fill the fuel pipe with fuel). |
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| In exceptional circumstances the fuel diversion system can also be converted without replacing the fuel delivery unit. Proceed as follows: |
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