QuestionHi John,
I have a 1994 300tdi disco. The heater no longer operates but the vent flaps in the heater box operate when the dials are turned. Is there a water valve? where would this valve be located?
AnswerHi Phillip,
this sounds like the heater matrix has failed. It can happen to older vehicles. The heater matrix is accessed by removing the centre console and thus the heating/cooling system is revealed.
Here's what the LR techsheets have to say:
The heating and ventilation system contains a heater matrix, which is connected to the engine cooling system, and a 4 speed fan for air distribution. Engine coolant is circulated through the heater matrix continuously, except when the temperature controls are set to COLD.
HEATER OUTPUT
Symptom:-Heater emits cold air.
1. Engine running: Check coolant valve opens as a temperature control is moved from COLD.
2. Check for engine running cold. See COOLING SYSTEM, Fault diagnosis, Engine Runs Cold
3. Check heater pipes and hoses for blockage or restriction.
4. Check heater matrix for blockage or restriction, flush system.
Heater emits warm air.
5. Engine running: Check coolant valve closes when both temperature controls are moved to COLD.
HEATER MATRIX
Service repair no - 80.20.29
Remove
1. Remove heater unit. See AIR CONDITIONING, Repair, Heater and Cooler Unit
2. Remove evaporator. See AIR CONDITIONING, Repair, Evaporator and Expansion Valve
3. Remove 2 screws and remove RH side footwell outlet.
4. Remove heater pipe clips.
5. Slide heater matrix from casing.
6. Release 2 clips and remove 2 heater pipes from matrix.
Refit
7. Reverse removal procedure.
You can try flushing your coolant to see if it frees up any blockage (even air blockage can cause this problem). If that does not help, most likely the matrix is fouled solid and usually is replaced.
Best of luck,
JohnMc
