Symptoms
Heater stays cold or lukewarm while the engine is up to temperature.
Likely cause
Air trapped in the heater matrix after coolant work, or a faulty heater valve.
Suggested fixes
Listed roughly in the order most owners try them.
- 1
Bleed the cooling system
Follow the bleed procedure with the front of the vehicle raised.
- Difficulty:
- Easy DIY
- Cost:
- £ (Under about £50 in parts)
- 2
Replace the heater valve
A sticking valve can stop hot coolant flowing.
- Difficulty:
- Moderate DIY
- Cost:
- £ (Under about £50 in parts)
This is general guidance gathered from owner experience and workshop practice, not a substitute for a workshop manual or a qualified mechanic. Costs are rough parts-only guides. Brakes, steering and suspension work affects safety, so if in doubt have it checked professionally.
Related faults
- HeatingMedium severity
Wet passenger footwell or sweet smell (heater matrix)
Damp passenger footwell, sweet smell of coolant, misting windscreen, coolant loss.
Series I · Series II / IIA · Series III · 90 / 110 / 127 · Defender2 fixes - HeatingLow severity
Heater fan only works on some speeds
Fan works only on the highest setting, or not at all.
90 / 110 / 127 · Defender2 fixes