Replacing a heater core



I may need to replace the heater core on my 96 Miata. I can get a salvage core from a Miata warehouse, or get a new one from the dealer for 400+ dollars. What to do?

I am also considering doing the replacement work myself due to the cost. Should I just pay the mechanic?


The labor will be expensive, and not using the best core available might set you up for a repeat repair job later.

I had the core replaced on a 1976 Ford Granada with A/C, and my mechanic friend said he would not ever want to do that again. The labor was about 9 hours. A Mitsubishi Montero needs to be virtually disassembled inside to replace the core; at least 10 hours of labor.

It’s a job I would not dream of tackling myself. Budget $900-$1000 and get the job done right.


I am in agreement with Doc. While the price for the heater core sounds high to me, the fact remains that this is not a job that you would want to have to repeat, so cheaping out on the part is not a good idea.

Incidentally–If you think that the parts price is high, wait until you see the labor cost, as this job requires removal of the entire dashboard on many cars.


I found a heater core for $100.00 at I’ve never purchased from them, so buyer beware.


I have not had a Chinese heater core come back on me YET. Unless you plan to keep the car “forever” I’d go with the $100 core. Japan is a lot closer to China than the USA is. The one from the dealer may well be built by the same Chinese factory.


Salvage isn’t the best way to get a heater core. Old ones frequently leak when the heater hoses get changed. Used heater cores are not a good deal.


Have you tried to see what a radiator shop whould charge you to replace the core on it if it is replacable? When I worked at a radiator shop 30 years ago we use to replace the core cheaper then a new one. We would soldier the hose end tank and bottom end tank to the new core and pressure test it. Don’t know if this opption is fesable now.


At a minimum, the dash will have to be removed. This is not a “$100 tool set from O’Reilly and I’m ready to go” repair.


I agree that the job is difficult and expensive, however I have never heard of a heater core costing $400. I hope my 13 year old core holds up a little longer!!


before you start tearing very expensive things apart, get a service manual and read the replacement procedure. Most PROFESSIONAL mechanics turn these jobs down and for good reason. Amateurs can really get themselves in a jam…The tricky part is getting everything to work correctly when you are done…


Go to and search heater core. You will find many solutions including step-by-step instructions. I recall Autozone or perhaps Advance had them for less than $150. It apparently can actually be changed out w/o removing the dash (instructions on This web site is the BEST source for all Miata questions. Good luck!!!