I don't use this car alot in the winter months, but recently made on long trip on a very cold day which showed up the facts that
1) the heater produces NO heat at all
2) the air output (hot or cold) is very small.

In the early stages of the trip the freezing fog meant ice forming on both sides of the screen (had to keep stopping to scrape it off) and later on I was just plain freezing cold - my hands went blue!

Something had to be done:

Triumph heaters did work ok when new, although the Heralds and Vitesses never had great blowers. So something had to be wrong.

First I dismantled the heater and flushed the matrix through with a hose. This did get some brown cack out but it didn't seem very blocked. I dismantled the valve and found that it was in dreadful condition, but, I thought more likely to allow excess flow that obstruct it (more on that later!)

I threw it all back together and found things much the same. No heat. This was odd I though as both inlet and outlet pipes were getting properly hot. After much discussion on the Club Triumph Forum, the consensus was insufficient flow, so I took it all apart again, unsoldered the end of the matrix (easy), manually rodded out all the tubes, pressure washed them and soaked in phosphoric acid for a couple of hours. The matrix was now definitely clean! Soldered it back together, pressure tested with the garden hose. Good to go.

Threw it all back together again. There was now a hint of warmth, but very unimpressive. I (and my panel of experts on the CT forum) was getting frustrated..... could it be that the baffle in the top of the matrix had failed and was allowing flow to bypass the tubes? Then, some illumination. The new heater valve arrived and I realised that I had mis-understood the workings of the original valve and it was in fact a major restriction.

All apart again. Also a quick trip to a local scrapyard produced two alternate modern blower motors that looked like they might fit.

- Mk2 Golf. Bayonet fitting, fan only slightly larger than the original Lucas item. Speed control resistors built into it.
- Nissan Micra (Rounded shape). Three lugged fitting, like the original but rather larger. Needs external resistors for speed control. Huge fan.

Finally decided on the Golf unit for convenience. The Micra one could definitely be made to fit and would probably deliver more air but requires more work and needs external resistor pack.

The heater front plate was modified to accept the new motor and the whole lot reassembled.

Testing proved that lots more air comes out of the vents and it's hot! Just need to sort the wiring so that I can switch speeds from inside the car (multiway switch).