Check delivery quantity of fuel pump.
| Possible defect | Remedy |
|---|---|
| Delivery quantity too small | Adjust delivery quantity |
| Filter blocked | Clean filter |
| Strainer dirty | Clean strainer |
| Fuel check valve blocked | Install new fuel check valve |
Check temperature regulation.
| Possible defect | Remedy |
|---|---|
| Check temperature sensor and temperature regulating switch | Replace temperature sensor |
Check adjustment of heater flaps on engine heat exchanger.
| Possible defect | Remedy |
|---|---|
| Bowden cable adjustment not correct | Adjust |
Non-return flaps in engine cooling air housing stiff or jammed.
| Possible defect | Remedy |
|---|---|
| Not installed correctly | Remove cooling air fan and check flaps. replace if necessary. |