HVAC fan - poor air volume output

[samx5]

I haven't been happy with the A/C on the NB8A and have had it tested, whereby the temperature of the air coming out is as good as it can be according to the Mazda boffins. The A/C system is working 100%. I then jumped in the family's NA6 and the fan seems to blow much more air out than my car on each fan setting, so the A/C is more effective. It's like all my fan outlets are partially blocked or the fan cannot blow much volume of air. It increases in volume and speed (and noise) on each setting, but the actual airflow out the vents is comparatively feeble. Does anyone have any ideas on the best way to investigate this? Is fan removal possible without major dash removal? Interested to hear if anyone has had a similar issue and how they solved it. Cheers!

[wassup]

Have you checked the duct work behind the glove box? It's a common issue when the connections between the blower and the evaporator unit aren't connected up properly or the seal between them has deteriorated...

[KevGoat]

Yeah as above. I had the glove box out in mine a few weeks ago and noticed the connector between those two was loose. I took it out (one bolt) and found the foam insulation was gone. Made up my own insulator and fitted it back in so that it was sealed and tight and now getting more air from vents. It also fixed the annoying dash rattle I'd had for a while

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[YanMa YatTai]

Can you hear the fan?
My NA had the flappy thing that flicks between recirc and external air break! It sat over the duct so very little air could get pass.

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[samx5]

Thanks all, I'll take the glovebox out and have a look. The fan is definitely working and does increase in speed, it may be that the air is escaping on its journey to the vents as others have said, and circulating behind the dash instead of coming out the vents. Cheers,

[samx5]

I pulled the glovebox and removed the clamp between the fan & evaporator (I assume that is what it is.....) and sure enough the seal was stuffed.


Replaced with foam and now it sits nice and tight with no air escaping from the seal.



There seems to be a bit more airflow, but I can feel air escaping at the top right of the evaporator, sort of between the evaporator and the black pipework on this photo:


I may need to disassemble more of the car. I am assuming of course that the system is meant to be sealed? I would also like to check the flap that controls the temperature from hot to cold, just in case it is slightly ajar and letting some warm air in. Are there any links that people have used that will help with this task? I'll start checking the Miata net site also.

[Snowmotion]

this is the link i used, http://www.miata.net/garage/heater_cable.html
, but if you remove the cowl under the steering wheel you will be able to the side of the heater unit and the cable that controls the heater flap.

Basically, the black cable that comes from the heater control ends with a wire wit a small loop at the end. This sits over the arm that opens and closes the heater flap.
If you pull the black cable from the clip holding it in place, turn the vent to full cold with the loop at the end over the adjustment arm. Then push the black cable firmly back in place.

This is the simple adjustment.

[samx5]

Thanks Snowmotion for the link. Tried this last night, took all of 10 minutes (including going inside for a refreshing Budvar) and was able to get another 5-8mm of travel towards the cold side. Although the weather has cooled down a lot here, the initial impression is that the air is much colder, so I think I'll put off doing anything more until the hot weather comes along again. Love the simplicity of these cars. Thanks all!