DIESEL FUEL LINE HEATER SYSTEM AVAILABILITY

Cadillac recommends the use of No. 1-D or winterized No. 2-D diesel fuels for temperatures below 20 DEG F. This is required because paraffin wax flakes form in diesel fuel at low ambient temperatures. No. 2-D diesel fuel contains more paraffin and, therefore, more flakes may be produced to the point where the fuel flow through the filters may be restricted.

A fuel line heater was included as standard equipment on some 1981 diesel equipped cars. This system consists of an in-tank filter with a built-in check valve and a heater in the fuel line prior to the engine mounted fuel filter. If the in-tank filter plugs with paraffin flakes, the check valve will open, allowing fuel containing wax flakes to be pumped to the heater. The heater raises the fuel temperature and melts the wax, thus preventing a restriction at the final filter.

Cadillac is also now making available, at the owner's expense, a diesel fuel line heater system kit. Owners may wish to consider dealer installation of this system based upon temperature conditions in their local areas. The kit can be installed on all 1981 models not so equipped and past model diesels equipped with a water-in-fuel sensing system except 1978 and 79 Sevilles (the kit cannot be installed on these vehicles due to the fuel tank design).

Owners who elect to have the fuel line heater system installed should be advised to keep the fuel tank more than one-quarter full when the temperature is below 20 DEG F. to help prevent the possibility of running out of fuel. If paraffin wax flakes form, the fuel tank sender has a check valve in case the fuel tank filter becomes plugged. If the filter plugs, not all of the fuel in the tank can be used because of the location of the check valve.

To perform a fuel line heater installation, it will be necessary to order a heater kit and a fuel tank filter with check valve under P/N 22514576 kit and P/N 5651973 in-tank fuel filter.

The suggested Labor Time for the installation of the kit is .5 hrs. with an additional .8 hrs. to install the in-tank filter. Complete instructions are described in Serviceman Bulletin 81-79.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.