Heater Matrix – removal and repair

Date: 26 Feb 2017


No heat or poor cabin heating? Wet floors? it is probably time to investigate your heater matrix. It may need changing or repair.


These much-overlooked parts block up with silt and rust over the years. A new matrix will not only improve in-car heating but will also benefit the cooling system overall.

Disconnect the inlet and outlet hoses on the top of the engine.

Connect a hosepipe and run water each way through the matrix.

If the unit is blocked the water will not pass through (you may get a trickle each way).

If the unit is leaking then your cabin floors are going to get wetter.


Extracting the heater unit

To remove and insert a heater matrix follow your manual.

In summary

  • Remove shelf
  • Remove glovebox
  • Remove facia mounted ashtray on later models (to give some light)
  • Drain system and isconnect hoses in engine bay
  • Remove air vent plumbing from heater unit
  • Undo the four bolts and drop the unit
  • Unplug the fan switch electrical connections
  • Wiggle the unit out

If you have a relatively standard car it takes an hour to remove and an hour to put back.

Also, worth replacing whilst it is out is the bulkhead seal (where the hoses pass through the bulkhead.

Figure: Bulkhead aperture ready for new seal

Note: I had to remove the choke cable and glove box to get the heater unit out (this is not listed in the manuals)

Dismantle the unit

Unscrew the heater matrix cover and pull the unit out (ok, you have to wiggle it and swear a bit but it will come out – maybe some penetrating oil will help)

Send unit for repair

Figure: Matrix ready for dispatch

Note: while the unit it out inspect the air duct seals and find some replacement seals (you will not find the originals, but find some self-adhesive sealing rubber and use this)

Figure: Seal failed on main flap


Approximate prices from: 26 Feb 2017

Replacement matrixMike Heming, Foursome Vehicle Heaters in Worcester – tel: 01527 64126.£130
Duct sealseBay<£10


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