Heat only on passenger side

[madkaw]

Never had this happen before, but I only get heat on one side of the interior. I'm not talking forced air- I have that both sides. Air only comes out warm on the passenger side.

I think there can only be one explanation for this - half the heater core is clogged.
Anyone else experience this?
I was going to try and backflush the core so I don't have to remove it- any suggestions??
I googled this and read somewhere that the person forced water through the core in the opposite direction and loosened junk up in there.

[SteveJ]

Are you sure the heater flap is open on the driver side?

[madkaw]

Yes, like I said, the forced air is coming out- just cold

[EScanlon]

Sorry but the premise that half the core is bad won't wash.

The heater plenum is a pretty basic unit, if you're getting heat out of it at all, it's available to both sides.

You're not making the mistake of expecting the heat to come out the eyeball vents are you?
Heat will NEVER come out the eyeball vents, they are strictly VENTS and Fresh Air Vents at that.

If you are getting heat to come out the passenger side of the bottom of the plenum when the levers are in ROOM mode, then you have something obstructing the driver's side of the door as the heater core is just above the volume of space that feeds both the passenger and driver side doors.

If on the other hand you're referring to heat out of your Defrost tubes when the lever is in the Defrost mode, and you are only getting heat out of the passenger side, then you have something blocking the tubing as again, the defrost tubes (R&L) feed from the same general area of the plenum.

FWIW
E

[madkaw]

I have restored these units so I am aware of how they function - that's why this is so bizarre .
No confusion on the vents. If something was blocking the heat it would also ne blocking air flow, which it isn't .
The only explanation is no coolant is reaching the backside of the core and the air is not getting heated.

[Captain Obvious]

I'm no expert on the HVAC system, but I was deep into mine and I can't come up with any possible explanation for what you're seeing.

As for your heater core theory... remember that the coolant runs from one side to the other, not between front and back. With that in mind, a partially clogged core does not support what you think you're seeing. If there were come clogged rods, it might be a little warmer in the front of the core when compared to the back, but not a differential between left and right.

If you are truly getting cold air out of one floor vent while getting hot out of the other, then I'm stumped.

[madkaw]

It is bizzare. I have a spare heater unit and have looked at it and can't figure how the warm air can split so evenly. Hopefully i will have a chance to mess with it today. I drained my coolant and plan on forcing water through the core in both directions to see how clean it comes out. I will just disconnect the hoses on the engine side and open up the heater valve and run water through that way. I REALLY don't want to have to pull this heater core because you know what kind of job that is. I have a spare that looks really clean.
This car sat for a really long time and I had the radiator flushed and it did have some sediment in it.

[Captain Obvious]

Yeah, pulling the heater core is no treat. I took my whole heater box out when I had the dashboard out of the car for other reasons, and getting to the heater core then is obviously cake. I took some pics of my box when I had mine completely apart, and I would be hard pressed to believe that the air blasting straight down on the bottom of the shell would split evenly as well. So, all that said, you've certainly got nothing to lose by flushing the heater core. I've got no other bright ideas.

How hot is the hot side? The greater the contrast between the two sides, the harder it is to explain any of this.

Another question... What do the defrost outlets do when you put it into defrost mode? Is one of them cold as well?

[madkaw]

The contrast is polar, that's what's crazy. True for heat or defrost.

Murphy's Law hard at work

[Captain Obvious]

Yup. I'm stumped. Sorry.

I've heard of a device in use a long time ago that separated a compressed air stream into a warm and cold stream*... Something on old trains maybe? Never studied it, but it always sounded like voodoo to me. Maybe that's what you've got going on?

So do the floor flappies on the side of the air box open enough for you to stick a finger up in there and reach the heater core to see how it feels? I'm grasping at straws, but it might lend a clue.

* - The Ranque-Hilsch vortex tube - http://en.wikipedia.org/wiki/Vortex_tube

[Mikes Z car]

I remember reading that NASA had a refrigeration technique that used compressed air or fluid with no other moving parts other than the air or fluid.

[Jetaway]

Never had this happen before, but I only get heat on one side of the interior. I'm not talking forced air- I have that both sides. Air only comes out warm on the passenger side.

I think there can only be one explanation for this - half the heater core is clogged.
Anyone else experience this?
I was going to try and backflush the core so I don't have to remove it- any suggestions??
I googled this and read somewhere that the person forced water through the core in the opposite direction and loosened junk up in there.

I had the same problem, warm air out the passenger side, cool air out the driver side. Tried many things, some of which worked a little, but the breakthrough was foam. Do you get a little cold air out of the vents even when the lever is moved to 'room?' If so, I suspect the problem is rotted out foam on the flap that controls the flow of air to the vents or 'room.' Buy some self-adhesive weatherstripping foam (1/2" open cell or 3/8" closed cell seems to work), pull the blower out, do your best to scrape the old stuff off with something, and use something that allows you to grip pieces of foam and guide them onto the flap as replacements.

I know. You're thinking how the heck rotted flap foam created your problem. All I can say is I had the same symptoms and replacing the foam solved it.

Chris

[madkaw]

BINGO!

The foam on the inside of the flapdoor peeled half way off blocking some of the heat.
The pain was trying to replace the foam without removing the heater box. I did loosen the heater box enough to slide it over to the driver's side so I could stick my hand in the fresh air side. What a PITA, but it's done-except for putting everything back together.

[Captain Obvious]

Excellent! Sorry I couldn't be of more assistance. Glad someone else knew what was going on!!

[Taz0162]

Time to convert to a right hand driver. Oh wait it's not that easy either.

[Blue]

Time to convert to a right hand driver. Oh wait it's not that easy either.

rofl