Heating Issues - Toyota Nation Forum : Toyota Car and Truck Forums

cykaaro · 09-30-2008, 12:02 AM

Well, with winter just around the corner, time to start thinking how to deal with my heating issues before it gets too cold to work outside.

This past winter I just dealt with the heater the way it was, but want to get it working properly if I can. I got the car ['92 V6 LE can. ver.] last december and knew there was a problem with the heat. It's not that it doesn't get heat per say. The cable that adjust the temp when left as is, seems to work ok, but when the heat is on, you have to push it to move the valve all the way over to be able to get actual heat, not luke-warm-still-freeze-your-arse-off heat. To me this is just a pita, as you either have blasting heat, or basically nada.
Being that the car is the age it is, and the valve design of how it heats, I'm thinking that the heater core needs a good flush to get all the crap out of it. I know from working with the jeep I had, it had the same type of valve idea to direct heat flow for heating/cooling inside the car. With it not being used for 6+ months it tends to get a sediment buildup in it. Back flushing it with a simple garden hose, and then forward, repeating until the water runs clean worked wonders. [anything more powerful will tend to blow the heater core]
Well, since I'm still learning about the camry, I'm wondering if my heating issue is simply the same thing happening, or could I be wrong? Everything seems to work ok, just not getting proper heat, and don't want to be freezing my ass of this winter. Any ideas I haven't thought of?

TIA

cykaaro · 10-08-2008, 03:21 AM

anyone?

Dave's · 10-08-2008, 07:42 PM

Couldn't hurt to flush it but it could be someone had the controls off and didn't reinstall them correctly. Book says it should be set to cool and then locked down while putting pressure towards the firewall. But it's also possible something is binding. IF it uses mechanical means to move the mixing valve I would suspect the cable to be binding. This causes it to 'flex' and build up tension. The tension can then build up enough to overcome the friction and the cable 'pops' to max heat. One way to test this possibility is to get it on max heat and then gently move it back to a cooler setting. They usually don't bind in both directions the same way. If this seems to work then you'll need to find out if it's the cable or the mixer which is binding. Just an idea to try since no one else was giving it a shot.

***new echo owner*** · 10-08-2008, 08:34 PM

Have you inspect the flow control valve for the heater? Or the heater core inlet and outlet hoses to see if they are both hot to touch?

N.E.O.

cykaaro · 10-08-2008, 10:41 PM

Valve works, and I do get heat, just not much. To get real heat going, I need to take the valve and close it all the way manually which doesn't work from the control knob but then it's full heat or none. I do know from experience that on really bitterly cold days it should be warmer than it is but that's years of sediment in the heater core that needs to be backflushed out.
The valve though by the control knob doesn't move all the way open. I can move it just a wee bit further.
I've not taken mine apart as of yet though as from trying to see how it works at the wreckers, there's not much room to move and I don't want to screw mine up totally.

I'm not sure exactly what you mean by 'locked down'. Does this mean where the cable connects to the valve? As well, on some I've seen while at the wreckers, the valve seems to be able to be manually moved further than the control knob does as well. Not sure if it's the same amount as mine or not. I just fear screwing the cable somehow and have no heat at all.

***new echo owner*** · 10-08-2008, 10:45 PM

If you can get full heat by moving the valve then the heater core is not plugged up. Which valve are you moving to get full heat? Is it the water control valve in the engine compartment?

I believe what he meant by lock down, is the cable housing retainer for the water control valve. On the bracket of the water control valve there is a clip that holds the housing in place, what yo do is set the temp control knob to full cold with the clip loose, then close the water valve to block the flow, then snap the clip in place to lock the cable housing down.

N.E.O.

cykaaro · 10-08-2008, 11:18 PM

Yes, the valve the cable connects to and moves.

The heater core isn't plugged up, but it does work at, what seems to me at least, is a reduced rate. Not as bad as my jeep was, but enough that when the temp gets really cold temps. It's the problem with this kinda of design. When you don't use it for half of the year it builds up sediment. The design of the jeep I could just eliminate the entire valve as it works on vacume to work, but with the camry, since it's cable driven it's not possible. Right now you don't notice it as it's only been getting down to 3*C overnight. With what is expected this winter, want to get it all working to the best of its' ability, and before it gets too cold to do it.

Will take a closer look at the cable and 'reset' it and see what that does. The knob as it is now goes to cold ok, but when you turn it all the way over to the right and let go, it backs off a wee bit. I'm wondering if the cable is indeed set wrong.

***new echo owner*** · 10-08-2008, 11:34 PM

If I remember correctly, the cable to the water valve doesn't come directly from the control, it actually goes to a cam, which also control the mix door, and then from there it goes to the valve. Will have to check to verify that though. Anyway, beside the water control valve, there is also a air mix door which directs the incoming air flow.

N.E.O.

cykaaro · 10-08-2008, 11:43 PM

For reference, I have a '92 V6 LE model, so my controls are the same as an XLE in the US.

Not sure about the mixing doors at all. From disecting one, the temp control section is held into the main unit by one screw at the front underneath the knob. This part snaps into place in the the main body. Now, I don't know all the inner workings of the piece, but coming out of it is a cable that runs through the firewall and directly connects to the valve. Nothing else appears to be connected to it, and all other connections run to the main unit. Except for that cable, the rest of the unit is simple unplug and pull it out.

***new echo owner*** · 10-08-2008, 11:48 PM

OK, it is different than I recall then. So you have the one with the knobs instead of the sliding levers. It would still have a air mix door.

N.E.O.

cykaaro · 10-09-2008, 12:02 AM

The typical LE one in the US [as I've seen a few recently at the wreckers] has the knobs with a slider mechanism. I think that is what works the mixing doors, rather mine has all push buttons.

Mine is like this one:

Dave's · 10-09-2008, 02:07 AM

Hey at least you have a dialogue going now. Here's the quote from my Haynes manual. "To adjust the air mix control cable, set the air mix to COOL. Install the cable and lock the clamp while applying slight pressure (away from the firewall) on the outer cable." The illustration is with the control panel inside the car pulled out. (Sorry, I said 'towards' earlier.) Believe NEO is correct for the valve side. Anyway, it may be flushing the core will solve your problem, however you say if you move the valve manually you have full heat. Don't think that would happen with a (even somewhat) clogged core. JMHO, but it sounds like the cable which controls the valve is maladjusted or is not being moved properly. What happens if you move the valve manually further than the controls move it but not full open?

cykaaro · 10-09-2008, 03:30 AM

It sounds like I may then be dealing with two problems. One the cable I'm really thinking isn't adjusted properly, the other the heater core is the usual sediment buildup.
What I mean by 'full heat' is that the valve is moved manually the rest of the way, which isn't very much, the end of the tab of the valve where the cable attaches moves maybe 1/8 to 1/4 more. What this does from appearance is totally move the valve that all coolant is forced through the heater core, which obviously creates more heat in the cabin. Now, whether or not the valve should do that, I don't know, as in other camry's I've been able to move them a bit more than the control knob can, which is why I'm thinking the core has too much sediment in it to heat properly, but that doesn't necessarily mean my cable isn't out of adjustment in which is seems it more than likely is a bit off.

***new echo owner*** · 10-09-2008, 07:24 AM

Quote:

Originally Posted by cykaaro

It sounds like I may then be dealing with two problems. One the cable I'm really thinking isn't adjusted properly, the other the heater core is the usual sediment buildup.
What I mean by 'full heat' is that the valve is moved manually the rest of the way, which isn't very much, the end of the tab of the valve where the cable attaches moves maybe 1/8 to 1/4 more. What this does from appearance is totally move the valve that all coolant is forced through the heater core, which obviously creates more heat in the cabin. Now, whether or not the valve should do that, I don't know, as in other camry's I've been able to move them a bit more than the control knob can, which is why I'm thinking the core has too much sediment in it to heat properly, but that doesn't necessarily mean my cable isn't out of adjustment in which is seems it more than likely is a bit off.

Maybe it is two problems, but it may also be one. You did mentioned that when you turn the knob to full heat it does want to stay at that position. Well, I am not sure how much it rotates back, however, if it is anything like a resistor it may have been enough to difference, so instead of sending a signal to the A/C amp to adjust the air mix door to full heat, this difference may have cause it to ratchet down slight to allow some cool air to mix in with the in coming air. Of course this is just a speculation on my part; furthermore, it wouldn't really do any harm to back flush the heater core. Sediment is possible in a system that wasn't very well maintained, if you had kept up with the maintenance on the cooling system, there should be minimal amount. You should also be able to check the bottom of the reservoir to see if there is any sediment since there isn't much turbulence there either to stir it up.

N.E.O.

davemac2 · 10-09-2008, 12:16 PM

You can always disconnect both cables: the one going to the mixing flap on the HVAC unit, and the one going to the heater core valve under the hood, and then perform each function manually to see if you can get maximum normal heat. The mixer flap can be seen and manually moved by sticking your head up under the dash at the driver's side to the right of the accelerator. Observe the movement of the flap arm as you move the heater dash control, then disconnect the cable and see if the flap arm actually has more movement towards the heat side than the cable will allow when attached.

As for your heater core, is your thermostat actually working correctly in the winter as per the temp gauge? ie. normal engine operating temps? I have my doubts about sediment in the heater core unless the cooling system has been abused and not been flushed every 2 or 3 years.

dave mc