Heater matrix replacement

[johng]

Over the past few months, I've noticed that my car is steaming up inside and I'm losing a small amount of coolant. My guess is that these 2 are linked and I have a slight leak in my heater matrix. Everything I've read says that for an A/C car, getting the matrix out is a real pain, but nevertheless today I started the job. So far it has taken me a couple of hours just to remove 2 sections of heater ducting.

Still have a third bit of duct to remove before I can even start to get the heater box out. Looks like I will be busy this weekend.

 

[johng]

Third piece of ductwork came out easily, just 2 screws that were actually reachable.

The heater box itself was not so easy. I failed to get the hoses off the inlet and outlet without getting soaked in coolant (but I did get them off). The remaining bolts holding it in were fairly easy to get to, but there is very little room to get it out under the dash without risking cracking the dash. In the end I had to remove the bracket on top of the heater box with the vacuum actuator for the hot water shutoff valve and also the kick panel in order to remove the vacuum actuator for one of the heater doors.


Then it was just possible to wriggle the heater box out (getting it back in is going to be fun).
Once out, removing the matrix is straight forward and I was very pleased to find a small puddle in the bottom of the box. At least I hadn't done all this for nothing!

 

[johng]

Made a bit of progress today, cleaned everything up (it was all pretty dusty) and fitted the new matrix to the frame.

All the seals on the vent doors looked to be in very good condition, but other than these there weren't any seals or gaskets anywhere else. I'm guessing that someone had taken the heater apart previously and rebuilt it without seals, as you can buy gasket kits for this, although they are not cheap. The DocRebuild website has some very good info on this, so I decided to make my own seals.

I made A, D and C from some self adhesive foam draught proofing and E from some packaging foam.


I was going to make B as well, but looking at my firewall I could see that the original rubber insulation actually fits between the firewall and the heater box, so there didn't seem much point in adding an additional seal here.

Getting the heater box back into the car wasn't as tricky as I had imagined. However, I did manage to trap a vacuum hose behind it, so had to remove it again to free this. Having fitted it a second time, I found I then had to loosen it again to be able to fit the ducting to the left hand end. Now I just need to refit the rest of the ducting, all of the centre console and the glove box. Oh and make seal F, reconnect the hoses and fill with anti-freeze.