Air conditioning and cabin filter (NC, ND)
The NC's air conditioning gets weak at idle and its refrigerant can leak, and the ND hides a cabin filter pocket behind the dash. This page lists what sellers describe and what an owner thread said. The NA and NB have their own A/C page, and the ND's cracked cooler pipe is on its own page. It is not a repair guide.
How to read it. Seller claims are as read on each seller's own page on 2 October 2026. Owner accounts are from Miata.net forum threads, dated below, and are individual opinions, not advice. There are no prices on this page, and nothing here was bought or tested.
| Seller | What it says it offers | Fits (as stated) |
|---|---|---|
| Moss Miata, A/C compressor and component kit | a new, original-equipment replacement-brand compressor; it says new units are free from contaminants, which helps protect the compressor from early failure | 2006-2015 NC |
| Moss Miata, A/C condenser | nitrogen leak tested, with high-density fins for cooling and heavy-gauge mounting brackets, described as an exact fit for an easy drop-in | 2006-2015 NC |
| Flyin' Miata, ND cabin air filter | a two-piece kit from Japan: a mesh cover for the cowl intake and an electrostatically charged filter for fine particles made of an antibacterial material; it says the ND has a pocket for a filter hidden behind the dash and that installing the kit is more involved than most | 2016-2026 ND, including the RF |
| Moss Miata, blower motor | listed simply as "Blower Motor" | 2006-2015 NC |
| Moss Miata, blower motor control module | listed simply as "Blower Motor Control Module" | 2006-2015 NC |
| Moss Miata, A/C evaporator core | designed to match the original in fit, form and function, leak tested, with an aluminium core | 2006-2015 NC |
| Mazda-Parts.com, Mazda heater core NE51-61-A10 | the genuine NC heater core; the retailer says to add your vehicle to confirm the fit | 2006-2015 NC |
| Mazda-Parts.com, Mazda heater core NA1P-61-A10 | the genuine ND heater core | 2016-2025 ND |
What an owner thread said
- A low-mileage 2008 with weak A/C at idle (July 2016). An owner bought a 2008 with 20,000 miles whose A/C was not cold. A service station found the system full of air, bled it and refilled it with oil, dye and sealer. The vents then read 39 to 44 degrees while moving but 55 to 58 degrees at idle or in traffic, cooling again once airflow returned, and he checked that the radiator fan was turning. One reply called the repair unprofessional: if air has entered the system the dryer should be replaced, and oil is not needed unless components were replaced or oil was lost. (Miata.net thread; first page, I did not read to the end.)
Search results for other Miata.net threads say that when the refrigerant gets low the system stops engaging the compressor clutch, so the A/C suddenly stops, that the NC is weak at idle and does better with the engine revved or on recirculate, that the condenser fins should be checked for damage, and that an overcharge makes it blow warm; I did not read those threads, so treat them as leads. Moss's search results also show a blower motor for 1990-2000 cars; I did not open that page.
A heater that stopped after a coolant change
- A 2007 NC with no heat (May 2016). An owner who had just drained and refilled the coolant found the heater stone cold though the A/C, fan and vent selector worked. One reply said he had an air pocket and should not drive until the system was fully bled. Another described the usual fix as heating the engine up, pointing the nose of the car up a steep hill with the heater on full and revving in neutral so the coolant reaches the heater core. (Miata.net thread; first page, I did not read to the end.)
Search results for other Miata.net threads say a dead blower is often the speed-control part in the blower module, and that blower noise is usually debris or a dry bearing; I did not read those threads, so treat them as leads.
Older cars. For the NA and NB, Moss lists a replacement heater core for 1990-1997 (917-400) and a heater hose for the NB (903-238, OE reference NC10-61-212). Flyin' Miata says the passenger-side heater hose, factory part NC10-61-211, fits all NA and NB cars, and advises cutting the old hoses off when working on the head because the soft brass or aluminium hard lines are easy to damage. I found no Moss heater hoses for the NC or ND.
Not covered yet
- ND A/C parts beyond the cooler pipe and the cabin filter, NC and ND heater hoses, and NC refrigerant capacities from Mazda.
- The outcome of the 2016 thread, and owner accounts for the ND.
© 2026 Fischer Interactive LLC. Written for the Ref Sensor app's Miata users. The seller's page is the authority.