Rebuilding my heater...

[ian65]

The heater in 1st gens are usually excellent but the heater in my black series 3 is useless / non-existant.
This has been ok in the warm summer months but now the winter is here, it's horrible!
I tried all the usual fixes like flushing / reverse flushing the heater matrix to no avail.
Back in the summer, when I bought the power steering setup off Tools JDM 12a turbo, I also bought the complete air conditioning setup off the car as well.
This comprised of the compressor, dryer, condenser, lines, loom, relays and evaporator and switches.
The system uses the standard 1st gen blower motor unit and heater unit with the evaporator sitting in between the 2 where the plastic line duct usually goes.
I'll start a separate thread for the air-con installation next year when I fit it to my car, but I've stripped and cleaned and rebuilt the heater box, heater fan motor unit and the air-con evaporator and I'm going to put the heater box into my car asap to stop me from freezing my nuts off

The heater box off the JDM 12at suffered from the usual old age woes typical of these 1st gen heater boxes.... the foam to the flaps has turned to dust and the unit itself contained 28 years of dust, flies, seeds and other debris that gets sucked into the heater system...















I split the unit by flicking the joining clips off it...















The unit was totally stripped and the case thoroughly washed out and dried.... the metal components were cleaned back to clean metal and cold galvanised and the platic flaps were cleaned back. All the flaps were then relined with new foam and the heater matrix flushed out and the unit blown through with compresses air to clear any dust etc...







Next the blower motor unit was stripped, cleaned and rebuilt...







The air-con evaporator was also stripped, cleaned and rebuilt...









Next step is to strip the dash and swap the heater boxes...... not looking forward to that one bit.

[chc]

Nice bit of work you've done there Ian, just like a bought one.
The facia removal etc actually isn't as bad as you think - check out my thread from the 'other' forum

I've a replacement unit here if for some reason yours still doesn't operate - it has your name on it.

[spoddy]

i agree, it looks like you just bought it
alot of elbow grease no doubt.

my little mx3 import blower fan has to be helped when i switch the fan heater on as sometimes the fan itself sticks.
so i hit the area under the dash where the passenger feet go with the steering wheel lock, just a gentle bump and
then the fan starts to move.

i take it the fan just needs taken out and cleaned and greased up again so it moves more freely?

[KiwiDave]

Ian

The unit that contains the blower motor, is that easy to remove without taking the dash apart? I've discovered that the cable which attaches to the recirc flap is just hanging loose so not attached to the flap. Also, the cable itself does nothing when I move the lever on the dash so I need to see what's going on.
Removing the whole unit will also give me great access to fix the pesky tiny rain leak once and for all.

Also, I received an AC condensor from NZ today. Would be nice to get it as clean as yours. It looks like I just have the core, you seem to have an interesting case which protects it. Don't suppose you have a part number for that??

[ian65]

Dave,

the only way to get the heater box out of the car without causing damage is to remove the centre console and the dash...... and it's a right bitch of a job which is why mine hasn't been done yet.... I can't face it!
I think Steves taken the dash out of Rexanne a couple of times..... you must have the patience of a saint Steve!

The heater cables just hook onto the outside of the heater box so you should be able to reconnect them without removing the heater box.... if you need any photos of where they connect up, let me know and I'll take some pictures.

aha, the air con evaporator.... the hens teeth of the entire aircon setup.
I don't have a part number but I've got a theory that you may be able to use a casing from a MK1 MX5. The casings to the evaporator in the 1st gens are handed between RHD cars and LHD cars..... you can adapt them to fit either but it's extra work. The actual box is the same but the panels that screw on each side of the casing to connect to the blower motor and heater unit are handed.

I think the chances of getting a genuine 1st gen RHD evaporator are almost nil..... but you never know!
AusRotary is probably the best place to look..... you might drop on an Aussie looking to shed some weight from his car.... plus they are RHD.

The altenative is to buy a LHD one from the states and then adapt it. The core is the same so you only need the case..... but this also incorporates the evaporator valve and the temperature control dial, so if you don't already have these, then you need them too.

[KiwiDave]

This is the evaporator, came off an ex-japan FB so proper rhd one. Will investigate the case thing.








and a compressor, off an ex saudi FB, needs a clean though....







If you could show me some photos of how the recirc cable fits to both ends, that would be really good. I guess i should get all this AC nonsense onto a separate thread... then you can upset me by telling me what bits I am missing and how similar to hens teeth they really are

[KiwiDave]

Hi Ian

If you scroll down to the 19th and 20th photo (jpegs 1914 and 1918), there is a weird looking spring type thingy inside the blower housing. Any idea what that is? Mine looks very much the worse for wear. Was wondering if it is anything to do with AC?

I was poking around trying to figure out why my recirc function does not work. I think I may be missing the spring in photo 18 (jpeg 1912). Anyway, will confirm my theory tomorrow.

[myatt1972]

I think its the resistor block for the fan speeds, it is inside there so the fan keeps it cool.

[KiwiDave]

I think its the resistor block for the fan speeds, it is inside there so the fan keeps it cool.

Another one for my dictionarium... weird looking spring type thingy = resistor block Thanks

[ian65]

yeah, Keith's right..... I've got a spare one here if you want it. PM me your address Dave