Thanks Steven, Will give the Vinegar a go when weather changes. I have a book, 501 uses vinegar has, putting in the heater matrix of a car isn't in the book. My heater is blowing very cold at the moment, good for the summer but not for winter. I don't suppose you have a link to the guide do you as a search is not finding it.
Regards Terry H
I think it was lost in the last upheaval of the forum as I can’t find it now. Added to that I didn’t take any pics when I did mine (doh!). It’s a time consuming project, but fairly simple.
1) Remove scuttle panel below windscreen (I’ve done it without removing the bonnet, but you might be glad of the extra space).
2) If you have an earlier four cylinder car you may need to remove the windscreen wiper mechanism.
3) Inside the car remove both knee bins.
4) Using every small extension you have plus a socket loosen (but don’t remove) the bolts securing the heater control levers. Counterintuitively you want to loosen the left levers by accessing from the right of the console and vis versa for the right. Under the bonnet unplug the wires going to the heater fan (right of the heater box near the steering box on RHD cars)..
5) Drain coolant to below heater level. Remove two hoses on left side of heater.
6) On four cylinder cars (can’t comment on V8s). Remove valve cover and cover camshaft to prevent dirt getting into engine. You need room to remove heater hence removal.
7) IIRC there are four bolts holding the heater down and (maybe) 2 holding it against the vertical wall of the bulkhead.
8) Remove heater from car (hooray!)
9) There are cast pot metal levers attached to shafts that run along the back of the heater. They will be very brittle from age now. I would soak in penetrating oil before attempting to remove them. They are a press fit into the shafts. Mark their positions before removal. Using patience a little heat and gentle force remove from shafts
10) There are tons of pop rivets holding the heater housing together. You need to remove those with a drill and the few self tapper screws. Take lots of photos before you start.
11) Now start removing panels. You should see the flaps inside with what looks like sand stuck to the surface of them or their matching slots in the body. That’s what’s left of the original foam used when the car was built.
12) Head down to Homebase (other DIY stores are available). And look for thin self adhesive sealing foam strips. You want something about 3mm or 1/8” thick or less. It should be very soft if possible and closed cell.
Foam comes in two general types:
open cell where each ‘bubble’ in it is open to the next one. This will retain moisture and rot out the box. Or
Closed cell where each ‘bubble’ is sealed so it can’t absorb water.
I found some about 13mm wide over here in the US. The thin stuff is for the internal seals. You’ll also want something closer to 15-18mm thick to make new gaskets between the bulkhead and the heater when you put it back.
13) Working through each part, clean off the old stuff. Paint if you want to (I did, didn’t want to have to repeat this job). And carefully apply the sealing foam to the flaps. Mitre the corners to ensure a nice flat, gap free corner to the seal.
14) Clean and repaint exterior panels. Re-assemble using new pop rivets and the old screws. Easy to say, as this takes a good while.
15) Refit by following the above backwards (again easy to say, getting the control levers back on is a royal pain).
16) Enjoy controllable beating and cooling.
Reckon on a good day to remove the heater, another day and half to carefully go through the heater and refurbish, and a day to refit.
I’ve probably forgotten a few things as it’s been a few years and I’m sure others will chime in.