Heater refurb

[torque2me]

Hi Groupies,

Time for a looksee at the heater system.

Vehicle is a 1977 2500s.

Whilst I'll start with the valve not being in the correct position i.e. open to allow hot water into the matrix, I have a funny feeling that will be blocked. Also the motor sounds like it can't be bothered to get out of bed.

Has anyone taken a unit apart? Rimmers sells replacement units (made by Claytons) but is much wonga. They also sell the matrix and motor as separate entities so I thought I would go that route.

I believe the TR6 unit is different externally (maybe not internally).
Kev

[iani]

I had no heat from the units in my Mk1 Estate or Mk1 GT6, in both cases I was able to restore service by flushing the matrix through. It doesn't seem to take much for these units to block up, well worth trying to flush, both ways if possible, and see if that restores service. The Mk2 heater valve could be a disconnected control cable, a weakened PVC sleeve on the control cable allowing it to move, preventing the valve from being operated or the valve itself being stiff, you can try moving it by hand.

Ian

[Charles H]

The Mk2 heater is usually a pretty good unit that provides plenty of heat. The usual suspect is the control valve on the side of the unit in the drivers footwell as mentioned before. Make sure it is in the fully open position and flush both ways using the stubs that go through the bulkhead as mentioned. Once the two rubber pipes are disconnected, it is pretty simple to push a garden hose on either end in turn.

[sprint95m]

The Mk2 heater is usually a pretty good unit that provides plenty of heat. The usual suspect is the control valve on the side of the unit in the drivers footwell as mentioned before. Make sure it is in the fully open position and flush both ways using the stubs that go through the bulkhead as mentioned. Once the two rubber pipes are disconnected, it is pretty simple to push a garden hose on either end in turn.

Yes, I concur, the mark two heater does provide good heat, certainly by the standards of it's era.
However a modern replacement matrix could still be worth considering...?
One striking thing is how compact the heater matrix has become in new cars.

I looked at this for a Dolomite Sprint(whose heater is poor compared to a 2000 mark 2) and fitted a VW Transporter matrix.
The VW design has much bigger tubes and inside each is what resembles an archimedes screw, the function of which is clearly to ensure
there is constantly hot coolant in contact with the tube wall. (I guess this is standard nowadays?)
It is possible to improve a Dolomite 1850 or Sprint heater's performance by employing an 88 degree C thermostat and taking the heater supply
from the cylinder head transfer housing (instead of the inlet manifold).
I am hoping that the VW matrix will offer a further improvement when I return my Sprint to the road (next year).


The potential problem with back flushing a heater matrix is that this only removes soft sediment....
the stuff that has set harder the concrete is staying put for sure.


thanks
Ian