RH 70 72 Posted June 21, 2021 Share Posted June 21, 2021 Anybody with a 70 explain this setup in the heater hoses.? What it controls, how it operates? My 72 does not have this. TY Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted June 21, 2021 Share Posted June 21, 2021 That is the heater control valve. On the 70 Monte Carlo it's located on the passenger fender well. For 71+ 72 it is on the intake manifold. It is supposed to shut off the hot water going into the heater core when the a/c is on or when cooler temps are requested. The quick version. Lol Quote Link to comment Share on other sites More sharing options...
Dtret Posted June 21, 2021 Share Posted June 21, 2021 So it’s vacuum operated via the control panel on the dash correct? Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted June 21, 2021 Share Posted June 21, 2021 Correct. Quote Link to comment Share on other sites More sharing options...
Leghome Posted June 22, 2021 Share Posted June 22, 2021 I did not think the 72 had those Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted June 22, 2021 Share Posted June 22, 2021 Not 💯 on the 72. Has to have something though. Here is a pic of "barn find" 71 402 Quote Link to comment Share on other sites More sharing options...
Dtret Posted June 22, 2021 Share Posted June 22, 2021 9 minutes ago, MC1of80 said: Not 💯 on the 72. Has to have something though. Here is a pic of "barn find" 71 402 That’s the same as my 71. Thanks for the information Quote Link to comment Share on other sites More sharing options...
jft69z Posted June 22, 2021 Share Posted June 22, 2021 None of my '72s (three of them) ever had that valve. I think it's done in the HVAC box with the blend doors, as far as choosing heat or cool air. Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 22, 2021 Author Share Posted June 22, 2021 9 minutes ago, MC1of80 said: Not 💯 on the 72. Has to have something though. Here is a pic of "barn find" 71 402 My 70, which I’ve picked up recently are the pictures in the original post. My 72 has nothing inline on the hoses. The overarching issue is that I am getting warm air through the vents of the 72. Heater door opens and closes properly, temp control lever works. Wondering if this setup on the 72 would fix that Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 22, 2021 Author Share Posted June 22, 2021 2 minutes ago, jft69z said: None of my '72s ever had that valve. I think it's done in the HVAC box with the blend doors, as far as choosing heat or cool air. I am getting warm air through the vents of the 72. Heater door opens and closes properly, temp control lever works. Wondering if this setup on the 72 would fix that Quote Link to comment Share on other sites More sharing options...
jft69z Posted June 22, 2021 Share Posted June 22, 2021 Just now, RH 70 72 said: I am getting warm air through the vents of the 72. Heater door opens and closes properly, temp control lever works. Wondering if this setup on the 72 would fix that Might work, but something else is probably wrong. May need to dig a little deeper. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted June 22, 2021 Share Posted June 22, 2021 Thanks for the 72 info. Only had a couple of them. Tons of 70 and 71s though. Lol 1 Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 22, 2021 Author Share Posted June 22, 2021 24 minutes ago, jft69z said: None of my '72s (three of them) ever had that valve. I think it's done in the HVAC box with the blend doors, as far as choosing heat or cool air. Yup, my 2nd 72, not on either one of them. Quote Link to comment Share on other sites More sharing options...
Dtret Posted June 22, 2021 Share Posted June 22, 2021 Didn’t all these cars have “some” warm air coming from the vents with everything off? My chevelle does it also with no a/c. Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 22, 2021 Author Share Posted June 22, 2021 36 minutes ago, Dtret said: Didn’t all these cars have “some” warm air coming from the vents with everything off? My chevelle does it also with no a/c. My 70, no. My 72, yes. It’s a mystery to me at this point Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted June 22, 2021 Share Posted June 22, 2021 A/c cars with a heater control valve should not have any warm air coming out the vents. Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 22, 2021 Author Share Posted June 22, 2021 42 minutes ago, MC1of80 said: A/c cars with a heater control valve should not have any warm air coming out the vents. My 72 has nothing on the hoses or the manifold. TY for your replies. Quote Link to comment Share on other sites More sharing options...
Leghome Posted June 23, 2021 Share Posted June 23, 2021 When I had my AC hooked up back in 2012 I had the same problem with heat coming in thru the heater vents Could never find out how to fix it so I had a valve put in the heater hose that I have to manually turn off in the summer or my AC does not cool off the car at all. Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 23, 2021 Author Share Posted June 23, 2021 2 hours ago, Leghome said: When I had my AC hooked up back in 2012 I had the same problem with heat coming in thru the heater vents Could never find out how to fix it so I had a valve put in the heater hose that I have to manually turn off in the summer or my AC does not cool off the car at all. Can you show a photo of that setup? Quote Link to comment Share on other sites More sharing options...
RH 70 72 Posted June 23, 2021 Author Share Posted June 23, 2021 Thank you for all the replies. A shutoff valve has been placed inline on the 5/8” hose off the manifold. No leaks. No warm air. AC is back to cooling the cabin as designed. On to Carlisle ! 2 Quote Link to comment Share on other sites More sharing options...
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