Heater control valve ???'s

[DeeVeeEight]

There is a valve that controls vacuum to the valve. It is attached to a cable that goes to your "Cold------Hot" control. When the lever is all the way to the cold position it should shut off the valve. Start the car and unplug the vac line to the valve. Move the lever from "Cold" to "Hot" and see if it changes.

Here is the shutoff on an C3 with A/C:

Thanks Larry, I have checked this valve and it works good. I will be going back into this area of the car to check all of the items on Jeff's "While you're at it" list. It should be fun on a hot humid afternoon.....:suicide:

 

[mrvette]

While your at it. Check the heater door cable adjustment. IT's inline with the cable. See that the full cold position has the heater doo shut. Check the MAX Air door under the right kick panel. See that it opens and closes fully. Check the vent door in the pass side cowl behind the debri screen. See that it moves open and closed. Pull the fan out and check for leaves. Change the fan ground wire to a #10 gauge black wire. Consider changing the fan to a C-4 unit with a spacer. Have the A/C charge checked. Check the condenser for debri.
That should keep you busy awhile.

Just did all that cleanout, pulled the C4/spacer fan out and got a ton of leaves/carp outta that evap housing...still don't trust I got it all, what got me is I can't find any outside air leaks, tried the light trick, tried all of it, check everything, still nothing....where in hell them leaves come from?? and it's STILL not as cold or as much air as I think it should have....

as I say I have just ONE leg of the heater flow blocked off, but it's up top next to the compressor, not down lo, the flapper is good, that much I have recently proven, it's on a servo motor from a later car also, once in position, it's not moving again.....

yet another mod, if this is going to be a continuing problem, I"m cutting the fender liner open even more, and cutting the lower pressure side of the evap box, making it removable so I can blast it out easy, with the motor itself.... then vac out the evap, put the trap door back on....:gurney::evil::shocking:

I figgered on permanent recirc I would never see any further leaves in there....obviously RONG, so another fucking mystery about this car.....
sorta goes along with the intermittant rough idle....

:gurney:

 

[BBShark]

Is the seal on the back/underside of your hood in place?

 

[big2bird]

Just did all that cleanout, pulled the C4/spacer fan out and got a ton of leaves/carp outta that evap housing.......where in hell them leaves come from?? and it's STILL not as cold or as much air as I think it should have....

From the fresh air intake on the cowl, pass side. Even when closed in Max Air, it opens when you shut the car off, and the vacuum bleeds down.

 

[mrvette]

Is the seal on the back/underside of your hood in place?

Just did all that cleanout, pulled the C4/spacer fan out and got a ton of leaves/carp outta that evap housing.......where in hell them leaves come from?? and it's STILL not as cold or as much air as I think it should have....

From the fresh air intake on the cowl, pass side. Even when closed in Max Air, it opens when you shut the car off, and the vacuum bleeds down.

The hood don't matter, yarn test over front end lift proved that, not that it matters any, the grill in front of the wiper door has been blocked off for one thing....and it's a convertible.....all the lift comes from in front of the radiator as I found out....

my outside vent is shut off, sealed shut the default/open spring cut and eliminated the footwell flapper eliminated.....

this morning, I stuck a hose down the open wiper door, and watched the water come out the fender bottom, and water gathered in a puddle under that oval vent to the inside....telling me that area is in fact a common area and in fact there is always outside air coming in on MY car, anyway....
my outside flapper looks different than those pix...not sure, maybe the old valve I cut off the flapper door, too long ago now....

so the only way around that is to take a ~5" hose and go from the fan hole to the inside of the car directly....no fender plenum....PIA...something else to mess with...drive Linda crazy otherwise, I suppose...

:drink::gurney:

 

[big2bird]

Is the seal on the back/underside of your hood in place?

Just did all that cleanout, pulled the C4/spacer fan out and got a ton of leaves/carp outta that evap housing.......where in hell them leaves come from?? and it's STILL not as cold or as much air as I think it should have....

From the fresh air intake on the cowl, pass side. Even when closed in Max Air, it opens when you shut the car off, and the vacuum bleeds down.

The hood don't matter, yarn test over front end lift proved that, not that it matters any, the grill in front of the wiper door has been blocked off for one thing....and it's a convertible.....all the lift comes from in front of the radiator as I found out....

my outside vent is shut off, sealed shut the default/open spring cut and eliminated the footwell flapper eliminated.....

this morning, I stuck a hose down the open wiper door, and watched the water come out the fender bottom, and water gathered in a puddle under that oval vent to the inside....telling me that area is in fact a common area and in fact there is always outside air coming in on MY car, anyway....
my outside flapper looks different than those pix...not sure, maybe the old valve I cut off the flapper door, too long ago now....

so the only way around that is to take a ~5" hose and go from the fan hole to the inside of the car directly....no fender plenum....PIA...something else to mess with...drive Linda crazy otherwise, I suppose...

:drink::gurney:

Then there only 5 possibilities:
1)You never sealed the outside air intake
2)You have a "Mistery" outside air intake
3)You never removed all the leaves after sealing the intake
4)Someone secretly adds leaves when your not around.
5)You have a tree growing inside your ducting.

 

[mrvette]

Is the seal on the back/underside of your hood in place?

Just did all that cleanout, pulled the C4/spacer fan out and got a ton of leaves/carp outta that evap housing.......where in hell them leaves come from?? and it's STILL not as cold or as much air as I think it should have....

From the fresh air intake on the cowl, pass side. Even when closed in Max Air, it opens when you shut the car off, and the vacuum bleeds down.

The hood don't matter, yarn test over front end lift proved that, not that it matters any, the grill in front of the wiper door has been blocked off for one thing....and it's a convertible.....all the lift comes from in front of the radiator as I found out....

my outside vent is shut off, sealed shut the default/open spring cut and eliminated the footwell flapper eliminated.....

this morning, I stuck a hose down the open wiper door, and watched the water come out the fender bottom, and water gathered in a puddle under that oval vent to the inside....telling me that area is in fact a common area and in fact there is always outside air coming in on MY car, anyway....
my outside flapper looks different than those pix...not sure, maybe the old valve I cut off the flapper door, too long ago now....

so the only way around that is to take a ~5" hose and go from the fan hole to the inside of the car directly....no fender plenum....PIA...something else to mess with...drive Linda crazy otherwise, I suppose...

:drink::gurney:

Then there only 5 possibilities:
1)You never sealed the outside air intake

Well, what we think of as the outside air flapper is sealed pretty damn good, from what I can see/get at not cutting the fucking fender off over this crap, enough with body work already.....

2)You have a "Mistery" outside air intake

Not a mystery per se, but somehow some ducting wraps around somehow, and so there is no water in the hinge #2 body mount...there is no water in the car, just water in a flowing 'puddle' seen with a flashlight, just under the recirc oval so the lower drain not up to a 1/2 inch garden hose....but the hot airflow is what bugs me....


3)You never removed all the leaves after sealing the intake

Possible, as the evap is the same as on all GM's of the era, and my old Pontiacs out blew this car, easy...it's much better when I cleaned this out as with any of them, but the slow accumulation was never a problem in the Pontiacs...why this one??:surrender:

4)Someone secretly adds leaves when your not around.
Ahhh....the water/fuel mystery.....FU, sorry...yeh I get leaves in the car when outside in the driveway....but I vac them out, not like a ton of them kicking round in the footwell....maybe it's just over time, one here and there....and also that water thing....something about that design or the possible changes by P/Owners, as it was a custom job from decades ago....


5)You have a tree growing inside your ducting.

well not surprised, the car IS more or less GREEN now, and I have seen pix one of the guys has that C2 in the side of a barn there for a avatar....

anything is possible.....:devil:

 

[010752]

Is the seal on the back/underside of your hood in place?

Just did all that cleanout, pulled the C4/spacer fan out and got a ton of leaves/carp outta that evap housing.......where in hell them leaves come from?? and it's STILL not as cold or as much air as I think it should have....

From the fresh air intake on the cowl, pass side. Even when closed in Max Air, it opens when you shut the car off, and the vacuum bleeds down.

The hood don't matter, yarn test over front end lift proved that, not that it matters any, the grill in front of the wiper door has been blocked off for one thing....and it's a convertible.....all the lift comes from in front of the radiator as I found out....

my outside vent is shut off, sealed shut the default/open spring cut and eliminated the footwell flapper eliminated.....

this morning, I stuck a hose down the open wiper door, and watched the water come out the fender bottom, and water gathered in a puddle under that oval vent to the inside....telling me that area is in fact a common area and in fact there is always outside air coming in on MY car, anyway....
my outside flapper looks different than those pix...not sure, maybe the old valve I cut off the flapper door, too long ago now....

so the only way around that is to take a ~5" hose and go from the fan hole to the inside of the car directly....no fender plenum....PIA...something else to mess with...drive Linda crazy otherwise, I suppose...

:drink::gurney:

If you're serious about air in these cars that's the best way. No leaks then and no leaves. :bounce:
Like I said before these cars don't have a real recirculate. Most GMs of that era had all the flappers etc in the boxes and they worked well. This design might have been good on paper, but in reality it sucks.
Half of the fenders I've had off, have had the adhesive missing from the factory in spots to make huge air leaks and a lot of others have some of the bonds broken, creating leaks. There is about 5 feet of bond joints in there and impossible to get at all the joints after the fact.

Since you just painted, I doubt you want to touch the fender, but you might be able to make a tube of some sort from the inside with the inner box removed, cutting into the cowl above the footwell fresh air flapper. Remove the original upper plenum flapper and a bit of the firewall seam. Run a tube from the fan hole to the side above the lower vent or even into the top of it.

I've only done it from the outside with the front off, but my goal was to have it cold enough so that annoying fan isn't on high all the time.
Down here in S Florida you need all the a/c you can get.

 

[DeeVeeEight]

If you're serious about air in these cars that's the best way. No leaks then and no leaves. :bounce:
Like I said before these cars don't have a real recirculate. Most GMs of that era had all the flappers etc in the boxes and they worked well. This design might have been good on paper, but in reality it sucks.
Half of the fenders I've had off, have had the adhesive missing from the factory in spots to make huge air leaks and a lot of others have some of the bonds broken, creating leaks. There is about 5 feet of bond joints in there and impossible to get at all the joints after the fact.

Since you just painted, I doubt you want to touch the fender, but you might be able to make a tube of some sort from the inside with the inner box removed, cutting into the cowl above the footwell fresh air flapper. Remove the original upper plenum flapper and a bit of the firewall seam. Run a tube from the fan hole to the side above the lower vent or even into the top of it.

I've only done it from the outside with the front off, but my goal was to have it cold enough so that annoying fan isn't on high all the time.
Down here in S Florida you need all the a/c you can get.[/QUOTE]

Do you have any pictures or diagrams to illustrate what you are describing?

 

[BBShark]

Here is a diagram of the factory HVAC system. I think it is a 68, but in principle they are all the same. Below that is a picture of the recirculate vent door (above kick panel vent) under the plenum.

DV8, I was asking you (not Gene) if you had the seal in place on the underside of the hood. That will allow underhood heat into the cowl area.

 

[big2bird]

I bet if you took a 75 w lamp at night, and stuck it in the kick panel door, you could find most any leak like that. Nice picture Larry.

 

[mrvette]

Here is a diagram of the factory HVAC system. I think it is a 68, but in principle they are all the same. Below that is a picture of the recirculate vent door (above kick panel vent) under the plenum.

DV8, I was asking you (not Gene) if you had the seal in place on the underside of the hood. That will allow underhood heat into the cowl area.

That pix there looks like my setup, upper flapper glued shut, and mechanism removed as it springs open normally....lower/inside air flapper removed entirely...

that ledge under the oval duct held water, but a open hose is a bit much and it was draining pretty good onto the floor....

so the mystery to me is, that water is visible from inside the car looking through that oval....that means there has to be a air unwanted air intake into that region....strange that the water flow area would combine with the air flow area...something is rong.....

from the look up top in that pix, there is a glass piece going across the top at a angle...looks like it would block water flow....??

Damnit, wish my vette shop friend was still active, I need a car to examine....

:stirpot::surrender:

 

[DeeVeeEight]

No, I do not have a seal at the back of the hood. I have an aftermarket hood so I guess I will have to get over to Home Depot and get some good foam weatherstripping and make a seal. I'll also try and see if I can't use some of the same weatherstripping to seal the area you have outlined in yellow. Has anybody tried any of the canned spray foam ("great stuff") to seal these inner fender areas?

Thanks for the pic and diagram!

 

[big2bird]

No, I do not have a seal at the back of the hood. I have an aftermarket hood so I guess I will have to get over to Home Depot and get some good foam weatherstripping and make a seal. I'll also try and see if I can't use some of the same weatherstripping to seal the area you have outlined in yellow. Has anybody tried any of the canned spray foam ("great stuff") to seal these inner fender areas?

Thanks for the pic and diagram!

I remember someone used something thru the kick panel door.

I would try the light bulb trick first to see if you even have an issue.

I may do this tonight myself.

 

[RMS73]

The fiberglass piece at an angle is the piece that forms the top of the recirc/fresh seal for the flapper valve. In the picture this flapper is opened allowing cowl plenum air into the fan. The picture showns in kick panel plenum. Water flows from the cowl plenum into this area and drains out thru the rectanglar opening in the bottom below the oval recirc door. The recirc door is recessed 1/2" or so so that the water runs area the opening and not into the car. If too much water goes down the plenum it is possible that the water will not flow out fast enough and build up a level to where it can over flow the recirc door opening.

When driving measure the air temp in the kick panel (side) plenum. I use my son or daughter for this. If the air temp is greater than the OS air temp then engine compartment air is getting into the side plenum. Likewise for the cowl plenum. The C3's had a seal between the firewall and the hood to keep the engine compartment air out of the cowl plenum area.

I used the Ford 4-port valve in years gone by and did not see any difference in it and a 2-port valve. When I complete my A/C work I'll go back with a 2-port valve valve in the supply side. I run a vacuum to this valve from a vacuum slide valve under the dash mounted beside the headlight override slide valve.

Roger

If you want to see some pictures of the side plenum look thru the pictures at:
http://www.supermotors.net/registry/16143/54522

 

[BBShark]

Some of the hose inlet sizes are not an exact match, a barb was used to make up the difference.

There is only one problem with this.

It is the second FORD part to be installed on my 'VETTE. :stirpot:

A little late but I found this 4 port valve with 5/8 and 3/4 ports so it should fix the port match problem. And, it will fix the FORD part issue also, this is used on a ton of GM trucks and SUV's :lol:

AC Delco P/N 155533:

 

[DeeVeeEight]

Some of the hose inlet sizes are not an exact match, a barb was used to make up the difference.

There is only one problem with this.

It is the second FORD part to be installed on my 'VETTE. :stirpot:

A little late but I found this 4 port valve with 5/8 and 3/4 ports so it should fix the port match problem. And, it will fix the FORD part issue also, this is used on a ton of GM trucks and SUV's :lol:

AC Delco P/N 155533:

It looks EXACTLY like the ford valve.

Thanks for posting this!

 

[mrvette]

Funny, that is the exact valve I pulled off the shelf, first shot outta the box, by chance at OReilly's parts house....it's on the vette now......16 bux with tax....PIA to install though....

:beer:

 

[BigBlockTank]

It is my MAMMORY that a dual control valve with one vac line is in a ~90's FORD truck....I been eyeing this trick myself....I know a Early C4 used a double action valve, and it was prone to rusting out though...the one I thinking of was some sort of black plastic, like the single action one I have in there now...but I know the flapper seals good, so have not bothered....maybe I should...

I like TT's trick of that sticky aluminum flashing for the a/c box, good tinking...

:smash:

This is a Ford valve that has 4 ports (although you can only see 3). When the heater core is shutoff, water is bypassed to the return. Rock Auto pn MotorCraft YG350

Good catch Larry. I might try that.
I do already have a ball valve, and just open/close it twice a year. I really need to finish my Dynamat job too. That should help loads.

I put DnyaMat in mine and there is no heat in the cabin. My wife puts her BARE feet on the carpet and says there is no heat. I like that DynaMat. It also controls the rattles. You'll see when you come for the Boneyard tour. It makes the stereo sound alot better, I'm an audiophile.

 

[mrvette]

I put DnyaMat in mine and there is no heat in the cabin. My wife puts her BARE feet on the carpet and says there is no heat. I like that DynaMat. It also controls the rattles. You'll see when you come for the Boneyard tour. It makes the stereo sound alot better, I'm an audiophile.

Audiophile...??? I have McIntosh.....4 ML2c's...two per channel, stacked....400 watts/Mac per channel, C31v preamp and of course equalizers....