I rebuilt my heater/AC assembly, thanks to some great posts here and the Bubble Tech foam kit. With the heater core out I want to replace the two o-rings on the "extension" tubes. I did abunch of research and can't seem to find dimensions and material for them or Mazda part number specific to the FD. I did find a number that seems to be common across Mazda's but not sure if it was the right one E301-15-287. Does anyone have any experience replacing these either with a Mazda part number or an off the shelf metric o-ring that work and you can share the dimensions. Based on my research it looks like EPDM is probably the right material for coolant vs Nitrile. Mine currently doesn't leak, but didn't want to take them apart unless I have an o-ring to replace them.

 

The FD parts microfiche lists 2 o-rings for the heater with p/n FD01-61-A19. Apparently, that part is NLA from Mazda, but there is an alternate p/n which is BF67-61-A19. You can try Googling that number to see if it's still available. Here's a dealer that I found (https://parts.mazdausa.com/p/Mazda__...67-61-A19.html), but it's probably best to call them first and check on availability.

 

Thanks @Hot_Dog I reached out to Ray Crowe and he confirmed and ordered for me, said they should be here Thursday.

 

Great! I hope they do the job for you.

 

Just to update the thread with more info in case anyone needs the Heater Core O-Ring details, or Mazda stops selling them and you need to source them.