Solved - solution posted - heat only from passenger side
 

Hey guys. I'm having a strange issue where only the passenger side of the car is receiving heat. Literally, half the vents belonging to the passenger side blow out hot air while the driver side vents blow out cold air. Any ideas what could cause this? Once in a while, I can get for a very brief period some heat from the driver side vents. This seems to occur possibly when I'm idling with the heat turned off. When I turn on the heat, i get some warm air from the driver side, but it seems to subside quickly and I end up with cold air. I think it subsides more quickly if I try to drive. I'll have to do some more testing to see what circumstances allow for some heat on the driver side for that very brief period, but for 98% of the time.. the driver side vents blow cold, while the passenger side blow warm/hot. Any ideas?

My solution in post #6: https://www.rx8club.com/showpost.php...80&postcount=6

i have the same problem, and i checked my control knob. someone else here said they flushed out the heater core but that did not work for me either. my car gets parked during the winter but i still want to know how to fix it. if you figure it out please let me know, so when i take her out in the soring i can fix it

how do you flush out the heater core? I have the service manual.. can you direct me to the correct page?

i'm sure you've already checked the air filter behind the glove box, right?

I did not, because a clogged air filter would produce poor ventilation, which is not the case here. I removed the hoses to the heater core and backflushed, and some gunk came out. I haven't put everything back together yet, but I will test to see if this fixes the issue, which I think it will.

Ok. Heat is working again, and it is now coming out burning hot. Since I see a bunch of people having this issue, I wrote up some instructions of what I did.

1) From the image below, I have indicated where the heater core is, the intake hose coming out of the engine block, and the outtake hose going back into the engine block after passing through the heater core.

2) The intake and outtake hoses can be removed at a few places, but I've indicated where I found it to be the easiest to access and to fit a garden hose. In order to access the outtake hose, you will have to remove the battery, and it's compartment completely. This is not difficult, as there are only a few bolts in the assembly and it comes off in several pieces.

3) The radiator hoses are held by a clamp. You will need pliers to release the tension and slide the clamp off the nipple (this is the pipe that the hose fits onto). The clamps can be difficult to remove, but wiggling them back and forth while forcing it down the hose helps.

4) Once the clamps are off, you will have to pull the radiator hose off the nipple. This is a bit difficult as its stuck on pretty good. I first rotated the hose to break it loose, and then I rotated as I forced it downward off the nipple. It will take some muscle and you will likely end up with calluses, but it will eventually come off. You can also buy a tool that will make it easier to remove, if you want.

Note: I removed the outtake hose first so I can drain the line from coolant (though there isn't very much). There is not much room to move the hose once its off the nipple, so I stuck a plastic shopping bag underneath to collect whatever coolant drained.

5) Take a garden hose and use a high pressure nozzle. Something like this is what i used: http://images.orgill.com/200x200/6813729.jpg

6) We want to backflush the heatcore, so you need to stick the garden hose in the outtake line. I connected some spare hose i had to the intake line and ran it into a bucket. I didnt have a great seal, but it was good enough that it didnt spray all over the place.

When I did this step, i immediately saw in the bucket some gunk that probably was blocking the heater core from passing hot coolant through.

7) Now you want to flush the heater core from the intake line to the outtake. Alternate between intake and outtake a couple of times to make sure its all out and the water is running clean.

8) After you've cleaned out the core, let the water drain out well from the outtake line. Once clear, slide the radiator hose back onto the nipple of both the intake and outtake lines. This can be a bit difficult, especially with the outtake line, but with some muscle and rotating it back and forth while pulling it up will eventually get it on. Once positioned, take your plier and slide the clamp back onto the nipple where it was before.

9) Put back together the battery and start up the car with the hvac off. Let the engine properly warm up before turning on the heat to test if its working. Once the heat is running, grab a flashlight and check the radiator hoses to make sure there are no leaks. Also, once the engine has cooled, open the coolant reservoir and fill it back up to the indicated line to replace the coolant that was drained.


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it's not the cabin air filter.....sounds like heater core to me as mentioned above

Thanks for the write up on this! Mother has been having some heating issues with the 05 shinka and this might be the trick!

Just wanted to say I was in this group as well - just finished flushing the core & the heat is about 2x stronger, and the driver side has heat again.

Just make sure you get the right coolant (glycol-ethanol, no silicates, etc)

I did the flush and all and still blows out cold air on the drivers side and still hot on the passenger side. Any ideas on what to do next? I need the heat to work as it has now snowed where i live! Maybe I did the flush wrong? Help!! Thanks!

+1. Replaced the thermostat and flushed the inlet and outlet lines of the heater core and still have the same problems, although it may be slightly better. What else can be done to fix this?

Anyone?

Try this: press and hold the POWER button and the SCAN up button simultaneously. A/C TEMP will show on your dash screen . Turn the heater know clockwise and see if the A/C TEMP numbers go up in sequence from "0" to "16".

It moves perfectly from 1-16 with every little turn of the knob so I'm pretty sure that, that is not the problem. I really need a fix its -30F outside!

I'm about to try this


Flushing with limeaway to dissolve anything plugging up the heater core.

If you don't have an air compressor, a bike tire pump might just work :lol:
Oh, wait... How about the portable one you can buy to pump up your tires :dunno:

Or just use a hose with an attachment to fit into the cooling system hoses.

I just got rid of my 8, but my solution here didn't hold up for very long. Heat on the driver side stopped working and I would only get it from the passenger side. No amount of backflushing the heater core helped thereafter. Think the only solution if multiple backflushes don't work is to replace the heater core or try pressurized air.

Just did the CLR flush of the heater core and I am pleased to say I CAN HAZ HEAT AGAIN! =D

How long did you leave the clr in there?

Agreed with the person above. I also want to know how long you put the CLR in?

hmm i notice mine is doing this too, i had a look thru the shop manual, and learned a couple of things.

the first being that the heater is constant flow, there is no heater valve, its always "on"

second they manipulate the temperature with a series of doors, however since there is only one set of doors, instead of left and right, having heat on one side pretty much can't be the doors, as they aren't sided. if there was no heat for BOTH sides, then the doors are suspect.

third. check the heater control like Grace Excel mentions, "Try this: press and hold the POWER button and the SCAN up button simultaneously. A/C TEMP will show on your dash screen . Turn the heater know clockwise and see if the A/C TEMP numbers go up in sequence from "0" to "16"." if the heater control is borked, then you're not gonna get the right results.

fourth, flush heater core! the inlet to the heater core is on the right side, which is suggestive of it not being hot enough, IE plugged.

fifth is that the engines thermostat is stuck open or something

when you have heat only on one side(passenger) it is most likely caused by plugged heater core

to this day I still have no heat in my car. Has anyone figured it out?

If you tried all these options above.. Proper flush and everything, have you tried replacing the heater core(325$) from Mazmart.