I got a GSL-SE that I'm gonna drive for the colder months, and on the way home last night, the whole windshield fogged up on me. I already replaced the heater control valve, but I checked it again to make sure - no leaks.I did manage to spot a lot of coolant through the openings in the heater box, meaning that my heater core is pooched. I can't find a single clue as to how you take these things out of the car, as the service manuals (Haynes and Mazda) didn't even cover interior/HVAC, so anybody got an idea?

 

here's how i'd do it. get an idea of the location by where the hoses go thru the firewall. then start taking things apart that's in the way of me getting to it.

 

Did this once on another make car (french car) and i had to remove the dashboard completely to get to the heatercore.....if you are able to do it yourself then do it, bringing it to the shop will cost enough.

 

i think the easiest way is to just pull the dash, it comes right out as an assembly with about 12 bolts.

there is an FAQ/guide somewhere, but there are 3 bolts on the top by the windshield, 2 on each side where the dash meets the door, and 2 on each side on the side kind of behind the radio, that's what the carpeted covers are for.

2 more bolts for the steering column, and it'll move out enough to unplug the speedo cable and the 2 big connectors

that's pretty much it for the dash, yes it is that simple.

once the dash is out the heater core is just sitting there

 

the dash MUST be removed in order to gain access to the heater core. here's a pic of the heater core location. keep in mind that it is sealed in the center heating unit, directly behind the radio.

 

damn! didn't know all that. can u imagine taking it in for a heater core and the mechanic telling u the whole dash had to come out? and the charge back then and what it would cost now. wonder how many 7s were parked because they needed a heater core?

 

Although frustrating to work on the little dude that designed these cars should have got a medal for it, every little nook has got either electrical or something stuffed in it.. In the 80's north American auto makers need a 1 ton to put that much stuff in.

 

That's what I was afraid of... Guess it'll have to wait awhile until I got the time to pull it out, and the money to pick up another heater core. Thanks for the info. I'll see what I can get together before it gets really cold, which isn't too far off.

 

pulling the dash only take about two hours, start to finish.. i've never had a heater core go bad. why do you think yours has gone bad? i have a replacement if you need it.

 

its only a 2 hour job! its not hard at all

 

o i know it's not hard to do. i'm just saying that for someone that don't know this stuff and taking it to a mechanic for a heater core and be told the whole dash has to come out might be kinda over whelming for some, and even some might say the car's not worth the cost after all these yrs.

 

The car i changed the heatercore on was a Citroen (don't know if these are sold in the US) and the core costed about $100 new. If i had brought it to the shop they would have charged me about $900 for a 2 day job......
Can't imagine a new Mazda core will be more expensive because i think they are also used in a 323 and so on.....atleast for the european cars.

Took me also 2 days but was worth it, only problem was i "forgot" some screws which i'm still figuring where they had to go

 

I kinda figured it wouldn't be that hard to do after I read mention that it's only 9-12 bolts or so. It's just that 2hrs (plus whatever another heater core's gonna cost) is something I won't have this week. I suppose it'll be a weekend job.

 

Yeah honestly, these are one of the easiest dashes to remove in my experience. I mean, the bolts are all relatively easy to get to and the whole thing is only held in by a few.

Unlike some dashes where you wonder who they broke the midget in five places to get some of them bolts there!

 

we used to have people fall over backwards over how expensive the part was! in the 90's!

 

My heater core failed me on a long trip. When I got in the car in the morning there was coolant puddling in the footwell. Nasty stuff. Take a weekend to do the job, stay organized with your screws its not too bad.

 

thank you!!! finally a thread that i can use. im doin the same thing hopefully this weekend( if my boss lets me out of work early) I got a spectra premium heater core (four seasons maker) from Autozone for $70, you can also get them from rockauto.com for the same price. Black Dragon auto has them for $130 but it isn't worth that much. But this has answered all my questions and confirmed my fears and suspicions. Just wondering though is there a way to sneak it(heater box) out without all the exta work? And do i need to disconnect the A/C or can it stay intact? (not a can of worms i want to open) Again lots of useable info thank you. Oh one last question to through out is the dash removal any different for an '85 GSL-SE?

 

Mine took 232k miles to go bad. At least I assume that's why the car was derelict. As soon as I got it running I was losing coolant and had a soggy carpet.

 

I'd say it held up well for the age and mileage. I wouldn't even be mad having to replace a heater core at that mileage.

 

I get the feeling Mazda made them for the life of the car, but this car had a particularly long life.

Longer still, since it isn't rusty and I'm giving it a LOT of love.

 

Does that mean you need a new heater core now? If so, I have one that I am giving away if you want to pay shipping.

Carl