I have a 05 rx-8 with 81k miles on it. I just bought it today. When driving today heat worked great. When driving a few minutes ago I drove it for about an hour and heater was on and heat was hot then cold then hot then cold. Car was not overheating the gauge stayed exactly where it needs to be in the middle. Car ran execellent and there is coolant in it. I'm starting to think there is an air bubble stuck in the heater core. Basically just wanted someone else's opinion and knowledge on the best way to get rid if the air bubble if it was to just drain the whole system and start fresh? It's a pressurized resivour and I didn't see any bleeder anywhere so it doesn't seem very easy to bleed.

 

it is probably the heater control ****. It's a common problem and if you are okay with mechanic work then it is a very easy thing to fix.

Try the diagnosis on this page to see if it is your control know.https://www.rx8club.com/series-i-do-...ontrol-158200/

 

Thank you for your advice I appreciate it. I will look into it. I'm
Not sure if that is the problem because I do have heat just not all the time. I'll be driving and I will have heat for 5 minutes as then cold air for 5 minutes and then hear for minutes. It just fluctuates back and forth that's why I was thinking there might be an air bubble trapped in or around the heater core. If it was that switch from what i understand I would either always have heat only or never have heat only.

 

It will do exactly that. Or sometimes be only cold. Just give the diagnosis a try it will take you less
Then a minute ti test it and know for sure.

 

Try the DIY Logalinipoo posted above

As far as I understand, a air bubble will cause the car to overheat, and most likely its your heater control ***** that are messing arround..Give that DIY a shot.

 

Ok I will give that a try for sure. Now that I think about it an air bubble with eventually move around and decavitate the water pump like you guys were saying and cause it to overheat and te temp gauge would also fluctuate when that air bubble hit the ect sensor. That's definetly not happening at all. I will try your diagnostics soon. Thanks for the help guys.

 

Yup you guys are awesome. Did the dash trick thing and it pulled up the ac temp and no matter where I turn the dial it stays on 0. If I okay with it a little bit
I can get it 16 for a second then it goes right back to 0. Since summer is coming up I will have some time to eventually get to that and replace that board behind there. Thanks for the advice guys.

 

Soldering it is a quick easy fix. It will take 1-2 hours to pull it fix it and put it back together. The joints are large and very easy to solder, buy i have some experience soldering. If you have none ask a few people. Soldering is very easy and you could practice a few times on a wire before actually doing it to your board. A soldering iron can be bought fir 10-15 dollars. They normally come with enough solder to practice and fix your controls.

Ill give you a few tips if you want to try it. At worst you damage a board you were going to replace.

 

Also, try finding your local meet group, take your 8 to the meet and ask the guys if they are willing to help you out and you can offer them some pizza and drinks.. ;-)

 

Alright I will do just that. I haven't ever done it before but it's worth a shot. I got a few guys that I know that drive some Hondas that are all fixed up for racing haha. As far as the 8, I'm the only one in county with one. I haven't seen one inside this 50 mile radios no matter which way I go haha. But yeah they might now how to do it and may be willing to teach me. I'm sure I could always learn a few tips off watching a YouTube video too. Mi biggest thing is taking everything apart and making sure I don't lose anything, break anything, of forget how it goes back together. I'll check out this stuff online a bunch first before I go and also make sure I take tons of pictures before I put it back together. So what was the problem with that heater control **** though? Did they just not attach the wires god enough and now they need re-soldered?

 

Yeah, probably. That's one of a few common problems. The sun visors breaking & taillight condensation are some others.

 

How about my heater in my car. It blows warm air in the passenger side but cold air in the drivers side when I set it to blow hot air. I've flushed the heater core but still does not work. my **** seems to be working fine and shows all increments from 0-16. Anyone have ideas?

 

Dude, just get a new heater core.

 

Don't bother messing with your heat core. That is not the problem. The problem is your blend door. One side the blend doors are working and on the other side it isn't. You need to find where that blend door is and fix it.

 

Skylerreniger did you have the same problem too?

 

I didn't have the same oroblem but i just recently got certified in auto heating and ac repair. To me it sounds like the blend door for sure. When you turn that dial from blue to red then it should open and close those blend doors. When you select red the blend doors will open allowing coolant to come through. The blower motor will then blow the hot air off of the coolant and through the ducts into the cabin of your car. If one of those doors is sticking then it will not allow the coolant to come through that section of the car and will not have any hot air coming through that side of the ducts. I
Can't be for sure that's the problem but that's what it sounds like to me without being there and looking at it.