In late January I had noticed the diesel burner light had gone out indicating a system fault. Using the diagnostic procedure in the Hydro-Hot manual, the problem was traced to a bad turbine motor. The diagnostic requires taking a voltage measurement at the control box terminals (C-5 ground and C-2 motor feed) when the diesel switch is turned on. If 12 VDC is present when the system is turned on and the motor fails to start, it indicates a bad motor. In this case the diagnostic procedure did, in fact, lead to the correct conclusion of a bad motor.

Shown above is the interior of the 12 VDC Bosch motor (0 130 067 017) used in the Webasto diesel burner. Notice burned commutator and worn out brushes. This motor exhibited intermittent starts owing to poor brush contact with commutator. The motor ran for about 4 years before failing. Given the price, it should have lasted much longer. Click HERE for large image.

Replacing the motor requires removing the diesel burner unit from the Hydro-Hot. Once the diesel burner is out, you'll need to remove the ignition coil (4 screws) and black plastic cover (4 screws) to access the motor. It's a good idea to inspect the drive coupling and replace it as required. The motor is mounted to a base plate that attaches to the turbine casting with allen 3 screws. Sizes are metric.

Overall it isn't a bad repair. Getting the black plastic cover off is a nuisance and getting it back on is a bigger nuisance. It's a good idea to mark the position with pen and tape before removing it. Inspect all wiring, connectors and spade lugs. Treat all electric components with care. Make sure to turn off the unit before working on it.

Evolve and simplify!
Scott Bridgman, Why not join and post your own comments?? (email me)