Defrost Turns the AC on WTH?!?!

[RodsGreen10]

I am going to get into it more today. Here is a blown apart pic of the system. Suggestions?

[Dead Parrot]

Checkout the following thread: http://67-72chevytrucks.com/vboard/s...d.php?t=460942

It has lots of good info on fixing the heater core and related doors and flappers.

To clarify my earlier post, your not connected vacuum hose probably should go to the vacuum pot that controls your recirculate door. Your post #11 has a better view of it behind the half dome.

[RodsGreen10]

Ok got to looking at old pics of the old motor. I see a difference in the way the heater core hoses are routed. In the original motor setup the pressure side to the core the hose was connected to the intake and then the return hose to the rad. On my new motor the pressure hose is connected to the water pump and return to the radiator. Could the fact that the pressure side hose being connected at the water pump now be causing a issue vs it being connect at the intake like the original motor. this has to be why I am getting a dribble on the return side to the rad. When I get home I am fixing this and testing.

[Chaplain]

Hmm

[RodsGreen10]

Originally Posted by Chaplain

Hmm

Hmm?

[Dead Parrot]

This thread seems on point for your hose routing question. The OP had his like you do with similar results.

http://67-72chevytrucks.com/vboard/s...d.php?t=559186

My 75 has connections from the intake and returns to the radiator.

[RodsGreen10]

Originally Posted by Dead Parrot

This thread seems on point for your hose routing question. The OP had his like you do with similar results.

http://67-72chevytrucks.com/vboard/s...d.php?t=559186

My 75 has connections from the intake and returns to the radiator.

Yep that is how my 76 original motor was setup. Happy I took a ton of pics. I will get this fixed and let you all know if it fixes it but it should fix it.

[RodsGreen10]

Old. Hose in intake.

[RodsGreen10]

New. Hose in water pump.

[motornut]

any leak it won't close outside air

[Chaplain]

That helped me and I'm not even working on my AC...yet.

[RodsGreen10]

Originally Posted by motornut

any leak it won't close outside air

Hell Ya. Thanks for all those pics that is very useful. I am missing some pieces on the kick panel to work that door. Need to find the parts to fix that.

[RodsGreen10]

Actually I am missing all of the Kick Pad Valve assembly. Now to hunt them down. Something else on the list lol. Which I have not seen those in any catalogs I have.

[Liberty]

Completely Normal for the A/C to be on with defrost, its designed that way.

I'd check to see if your heater hoses are even getting hot. And obviously the truck has to be at operating temperature.

[motornut]

Originally Posted by RodsGreen10

Actually I am missing all of the Kick Pad Valve assembly. Now to hunt them down. Something else on the list lol. Which I have not seen those in any catalogs I have.

maybe plug the hose and use the non- AC/manual type till you find it

88 shown

[RodsGreen10]

Originally Posted by motornut

maybe plug the hose and use the non- AC/manual type till you find it

88 shown

Ok. Thanks.
Yep that's what I need. Tease me with a pic lol.
Do they repop those?
Thanks

[RodsGreen10]

Got heat. Took hose from water pump put on intake got heat lol. I looked at old pics of motor and my new setup over and over and over and it was right in front of my face. Took me a couple of days had to order a fitting. Works great! Thanks for all the help.

[Chaplain]

Thumbs up

[bnoon]

Originally Posted by RodsGreen10

Got heat. Took hose from water pump put on intake got heat lol. I looked at old pics of motor and my new setup over and over and over and it was right in front of my face. Took me a couple of days had to order a fitting. Works great! Thanks for all the help.

I wish I would have seen this thread earlier!!! Same thing happened to me when I changed around my 350 last year. Glad you got it settled!