need some help where to start. i have a 04 RX8 that last year took forever for the heater to heat up. i work 15 minutes from work and most of the time it wouldnt heat up in that time. normally happends on colder days. where should I start. I checked the coolant and it was good and I replaced the termostat last year, no help.. give me some ideas where to go from here..

thanks

 

Are you getting any flow through the heater hoses? Feel them when/as the engine warms up and the heater is on, one should get hot(engine temp) and the other should be cooler as it looses heat to the cabin, if they are the same temperature your not transfering heat (no/low airflow) from the heater core to the air, if one gets hot and the other stays cold your not getting coolant flow through the core.

 

where is the heater hose located at, I dont know alot about the Mazda's.

 

There should be two fairly large hoses going through the firewall behind the engine, I have never seen the engine compartment of a RX8 (or even 7 for that matter) so I cant tell you exactly where they are.

 

Check the heater/ac controller. Those things are notorious for going bad in the RX8.

 

Thanks MazdaTirol I'll look at them, so one should be hot and the other should be cooler but not cold right?

Thanks Mazda Trini, I had heard of that before, is there any way of checking to see if the ac/heat controller is bad?

 

Correct, it should still be warm if all is working ok since you didnt take ALL the heat out of the coolant to heat the cabin. I didnt know about a controller for the H/AC, thanks Trini!

 

Check the cap. Some people think the screw-on style can't go bad. They can.

If you want you can try loosening it after up to temp (cover your hand with a glove or towel) and listen for a release of air. If it's not a fairly strong release, it's possibly bad.