Heater Core

[EvilU]

Thanks Green,

Got a complete NB Heater box from MX-5 Mania for $150. I am going to put it in next weekend. Thansk for you information.

Evil U

[Mr Morlock]

that seems much better than laying out really big $$ for the new OE components- Mazda must have enormous mark ups.

[EvilU]

HI All,
Finally got the heater core in on the 25th. Firstly the heater box supplied by MX-5 Mania was fantastic. It was a later NB heater (obviously I have an NA) but if you replace the whole unit they are interchangeable. The core, tubing and foam on it look basically brand new. Very happy for what I paid for it. Secondly the instructions http://www.miata.net/garage/DashRmv_89_93.pdf are invaluable. We changed the order of some things but on the whole we followed them. We started at 9:00am and had the whole lot back together by 2:30pm. That was two guys working pretty steadily except for a half hour lunch break. New core has been in for a over a week now and there is no smell of coolant any more

So what went wrong?
Someone had fitted a alarm that has since been removed. The wiring under the dash was left in place and prevented us from dropping the steering column. It was a few tense moments while we figured out we could safely cut wires out of the loom. I still had my fingers crossed when it came time to fire the MX-5 up the first time.

I manage to snap 2 of the 3 clips and the guide pin when I removed the instrument hood. The old man did a fantastic job to gluing them back on. One of the clips came of when I refitted it but even without it there are no squeaks.

Lastly and probably most importantly, if you have air-conditioning in the you MX-5 you will need to disconnect the pipes leading to the unit mounted in the car to get the heater core in or out. We did see this any of the reading we had done (the above PDF or the Enthusiasts manual). Luckily my system lost its gas a long time ago but if you’re doing this job you may want to get it safely purged before you start the job.

Oh and the unit was definitely leaking, see the pics provided

[greenMachine]

Good work catching it before the leak caused more problems.

I hope you are using coolant, not water, in the system - I notice from the green stains on the old one that it seems to have had decent coolant in it, or was this the stuff you put in it after you got the car?

I hope all your motoring is now trouble-free and grinfull !!

[Pamex]

Pull it out and check it. Mine had been weeping for a while, but it was actually the hoses. They looked pretty bad, and when I pressure tested mine, the core didn't leak. It was the small bits of rubber hose on there.


If it's your core, take it to a different radiator shop. They should do them.

I'm in the process of re-conditioning mine. All the foam has disintegrated on the flaps, so I've replaced all of that, and re-greased everything.

Sorry, just read on. Glad you're sorted.