mkhargrove

Tom, if the heater valve is all out open, it will feel like someone shooting heat guns through your vents. Even if you have your AC running...
If it's just uncomfortably warm, I'm still thinking its likely that you're getting warm are from the fresh/recirculate vent. It's easy enough to tell. As I said above lean under the glove box area and you'll see a small hole in the middle of the panel that's the bottom of the ac box. You can literally push up in it and touch the vent flap. If it's open, you're sucking warm air in from outside of the cabin.

beran earms

I am having the same thing and I have replaced the valve with a new one and it is in the correct direction, when I feel in the square cut out in the bottom of the air box I feel the flap in the down position. I can push it up and it does have resistance but moves solid and smooth. Can some one explain are we to push it up and hold it up with something, and this would be its closed position? Flap down means opened and flap up is closed? Is this correct?

FredR

The term "open or closed" is somewhat confusing as it depends on one's understanding of what the flap is intended to do.

I think it is better to refer to the options as "fresh air mode" and "recirculation mode". To enable recirc mode the actuator has to be functional and vacuum applied- this causes the flap to swing upwards and thus cut off the fresh air inlet port. When the actuator is tired the flap does not pull up completely and it does not take much to impact the air conditioning dramatically.

beran earms

Thank you Fred, perfect explanation!

Tails

The heater valve is a plastic gate valve and will deform with heat over time.
I solved my problem many years ago by installing a spherical shut off valve in the heating water circuit that stops flow to the A/C heater. I located the valve in the circuit after the "Y" piping where one line goes to the engine cooling water header tank and the other goes to the A/C heater. Unfortunately in the design the system for cold climates, the heater core is installed ahead of the A/C evaporator. By installing this valve it stops nearly all water flow to the heater core when the engine is running. When the engine is switched off the hot water will enter the heater core via thermal cycling, in reverse, as the vacuum system is not operating and the gate valve will open. This is the reason why there is hot air coming out the vents initially in the summer time until the A/C cooled air overcomes the heated air.
I fitted this spherical valve over 15 years ago and when operating in summer I keep it shut. Some pundits say by fitting the valve will cause corrosion inside the heater core, this has not happened as I keep my cooling water inhibitor in excellent condition giving excellent protection to the alloy parts in the cooling system.
Major A/C problem solved in hot climate and you will get cooler air into the cabin..

mkhargrove

I think we need to get Roger to manufacturer a bracket made specifically to clamp up in the "square hole" that pushes the flap to "recirculate"
It seems like about half of the guys I chat with have some type of very long term temporary solution rigged up to hold that flap closed....

hacker-pschorr

Or just replace the vacuum actuator so it works as intended. It's not like the necessary parts are not available or expensive. Sure it's a bit of work but better to encourage people to fix it right.

mkhargrove

i've replaced 3....still trying to sort out the controller. along with 4,682 items on the to do list.

dr bob

FWIW, except for the HVAC clutch relay, not a lot happens in the controllers that can't be solved with an art-gum eraser and a bit of spray contact cleaner. Behr used some thin grease/petroleum jelly to lube the slide-switch pads on the board, and those can be cleaned off and re-lubed.

There's a "truth table" in the WSM that describes the various vacuum solenoid and actuator positions for each of the various modes. Follow that to make sure that the right vacuum is going to the right actuators at the right time.

I did find that all the actuators need to work correctly plus not leak vacuum if you want the rest of the system to function correctly. A little opposite of the question about Tom's situation, I found that having a vacuum leak in the actuator diaphragm of the heater valve was enough to keep the rest of the actuators from maintaining their correct positions. Result: warm air with AC running. The water side of the valve was sealing tight when the valve was zip-tied closed OK, but other warm air was finding its way in and keeping center vent temps above 50 or so. They typically run less than 20ºF with the freeze switch jumpered, so it was way too warm. All from the vacuum leaking through the leaking HCV diaphragm.

928NOOBIE

Or you could be lazy like me and put a ball valve inline

I did in fact create an electronic solution for the vacuum valve. I took the I believe red lead.....which is energized when the heater is not running/opens the solenoid to allow vacuum to close the heater valve...unplugged it from the solenoid and used that as a trigger to a relay I put into a spare socket on the fuse panel, leached some power from the cigarette lighter to an un-used fuse socket..put in a 5 or 10 amp fuse I can't remember to run the relay than ran it under the hood...problem is getting a heater valve that works as default/unenergized when open and powered to close. I got one from Thermotion but it wouldn't close all the way...maybe the pressure is too much but I took it out but the concept works flawlessly. I used a cheap valve I got from what was probably China for concept testing but it wouldn't allow enough coolant to flow for the heater and eventually gave up the ghost...but it was super cheap.....and proved my solution works.

I still have the solution rigged up and it is a frigging awesome solution..just need the valve.

dr bob

I remember sourcing a British Ford valve that exactly duplicates the connections for the factory valve but works opposite the factory valve. My thinking was that I could place it in series with the factory valve, and plump the vacuum to the supply for the dampers and FPR. So valve opens only while the engine is running. Easy no-muss and no operator actions required to keep coolant from circulating with the engine stopped.

GregBBRD

Many times, we find that the "mixing" door has lost the foam that seals it....due to age. There's enough "reverse" flow through the system so that there is always hot water in the heater core. If the foam seal is damaged, no amount of adjusting or replacing of parts will completely keep heat from entering the cabin....the heat goes right past the gap from the missing foam and mixes with the cold air.

We frequently add in a second heater control valve on the return side, to keep as much water from reaching the heater core as possible.

mkhargrove

Hey Greg -
Will foam weatherstrip that's used for residential doors (from Home Depot) work as a replacement for the foam seal on that door? There are several different width's and thicknesses....I wouldn't trust the adhesive backing that comes on the foam to work but with the right adhesive I'm not sure why it wouldn't. I'm curious if you have tried anything like that


https://www.homedepot.com/p/M-D-Buil...E&gclsrc=aw.ds