Any heating & A/C gurus out there ?

[mrbelv2]

I'm wondering if I can do away with the firewall mounted heater control (see attachment)and just install one inline in the heater hose
running to the heater box? Would the system operate properly? How does the capillary tube and probe function? The reason I want to eliminate the factory control, is that leaks go into interior, want to clean up firewall etc... Vehicle is a 66 B body, factory air. I plan on keeping factory box and upgrading underhood components. I called Classic auto air and they couldn't definitively answer my questions, so I'm going to the experts! There are some experts on here.....aren't there?

[Chatt69chgr]

Use search feature and type in water valve or heater control valve.  Several posts on this valve.  I think the capillary tube senses air temp in the heater box ducts and modulates the flow of hot water to the heater core vial the heater control valve to try to keep the temp constant.  I think the bowden cable that runs from the air temp control on the dash actually moves the valve to different positions from open to shut and that the capillary tube just fine tunes whatever setting the temp control is moved to.  I may be wrong on this.  The guy in California that rebuilds these valves doesn't have anything to fix the capillary tube with and told me that most of the capillary tubes are no good anymore anyway.  If you search around on here you will find the name of the guy in Calif and it's Jim something or other.  I think he charges something like $125 to rebuild these.  He not only replaces the gasket between the copper tube and the steel part that bolts to the firewall (thats what leaks into the interior) but the rubber part that performs the actual valving action.  YOu can get the gasket from NAPA but not the little rubber part.  You can rebuild this about once and that's it.  Was never meant to be rebuilt.  I'm thinking that a bowden cable operated water valve would do the same thing.  In 70, they used vacuum to operate this instead of the bowden cable I think.

[mrbelv2]

Thanks for the reply. I have practically worn out that search feature on here and on other boards. I did find the guy you mention, but would really like to get rid of this valve and weld the hole in the firewall.(I'm redoing eng. compt. now) I put the sensor in hot water and also ice water and didn't see any difference in the operation of the control valve. I thought it might sense evaperator icing up and momentarily allow heat into heater core - or, it operates as you said, to control heat into core for heater operation. ? I just don't know for sure, and would like to find out before I weld the hole shut.

[Chatt69chgr]

I'm hoping that someone on the site that really understands how these things work will chime in and educate us.

[mrbelv2]

Me too. I can't seem to find this info anywhere.

[redfourjohnd]

Me three. I've got a valve like this on my 62 valiants. $75 to $150 for NOS replacements.

Thanks,

John D

Edit: Fairly good link I haven't seen before: http://www.onlineautorepair.net/1/post/2009/09/heater-control-valve.html

[Chatt69chgr]

Looks like I was right about the capillary tube:

Cable operated types are control directly from the control lever on the dash mounted climate control center.

Thermostatically controlled valves feature a liquid filled capillary tube located in the discharge air stream of the heater core. This will accurately determine the air temperature blowing at the driver.

A thermostat control valve will modulate the flow of hot water to maintain a constant temperature selected by the driver.

So I think our water control valve is a combination of the cable type and thermostatically controlled type.  The guy in CA that rebuilt mine doesn't have the ability to fix the capillary tube and said most of them are bad anyway.  Said that the cable will operate the valve OK.  You would just have to occasionally fiddle with the temp setting to keep the warm air inside the car at the temp you want it.

[mrbelv2]

Thanks for the link and replies. I think I'll go with my plan to use a manually operated valve. Hope it works ok!

[redfourjohnd]

I got a plastic version of the manual valves on this page: http://www.bouchillonperformance.com/BPEheaterValve.asp at carquest. Ten or twelve dollars I think.

I haven't mounted them yet but I imagine they will work fine.

John D

[mrbelv2]

Perfect. Thanks!

[Chatt69chgr]

If your water valve is leaking you can replace the gasket that is between the copper tube portion of the valve and the steel firewall mtg plate portion.  It's available from NAPA and is cheap.  You have about one shot at carefully bending up the ears on the copper tube assembly but it can be done.  If your capillary tube was defective or just missing, then you are controlling the water flow manually with the bowden cable.  Note that on 70 chargers, this same valve was used but it is vacuum controlled.   Too bad that this part has not been repopped since this same valve was used on lots of different vehicles from several manufactureres.  I have seen valves similar to the one that Bouchillon sells used on Chargers.  They ran the cable out through the firewall to the valve and the valve was just supported by the heater hoses.  Got the job done but didn't look real good. 

[Hemidog]

http://www.dodgecharger.com/forum/index.php/topic,64251.0.html
http://www.dodgecharger.com/forum/index.php/topic,52190.0.html