New Heater Valve NO HEAT??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

VanceH · 10-02-2009, 03:50 PM

ok i have a 72 jimmy with A/C, i was always getting heat, so i replaced the heater shut off valve, and now i get nothing but cold air??? I thought i had it on backwards so i turned it around but still the same???

Any ideas

thanks
Vance

**Classic Heartbeat** · 10-02-2009, 04:00 PM

2 things to check. 1 is the valve working? If not do you have good vacuum going to it? 2 Is your system full of water? WES

**john** · 10-02-2009, 04:19 PM

Do you have the right valve? some open with vacuum others close with vaccuum. Just a thought.

VanceH · 10-02-2009, 04:20 PM

Not sure how to check if it is working?? Where is the main vacuum block for this? and plenty of water. The old one was not shuting off so i was getting hot air all the time, there is a vent under the cowl that is ran by a vacuum as well??

thanks

VanceH · 10-02-2009, 04:21 PM

It was the one that LMC had?? Ihope it was the right one.

**john** · 10-02-2009, 04:49 PM

Might check the source. Looks like it should heat with no vacuum to the valve. Good luck.

VanceH · 10-02-2009, 05:18 PM

where is the source? and were is the control head vacuum switch, i am assumming that it is under the dash somewere???

**john** · 10-02-2009, 05:46 PM

Goes from the vacuum reservoir to the backside of the a/c control on the dash. Some models have three lines on the control instead of two with a tee as shown.

VanceH · 10-02-2009, 06:23 PM

ok found the control head switch, the lever that ran it was broke, now fixed, also i found the vacuum res. it had no vacuum lines at all, i found the one from the switch, but i still dont know where the source is?? What does the vacuum source look like, is it off the carb??
Sorry for the trouble

thanks
Vance

**john** · 10-02-2009, 07:01 PM

Vance, the source is anyplace you can find full vacuum. Ususally on the intake manifold fitting behind the carb, or off of the carb itself.

VanceH · 10-02-2009, 07:03 PM

LOL ya figured that one out, been a long day, i have it all hooked up and still not enough vacuum to open the valve, i can suck it open so i know its working, i guess ill head out and tinker some more. Thanks for all the help

vance

**john** · 10-02-2009, 07:18 PM

Sometimes the lines just get old and split or crack or fall off. sound like you're on the right track.

VanceH · 10-02-2009, 07:22 PM

Ok what does the vacuum resorvior actually do? can i bypass this totally, if i hook up each of the vacuum valves to the main source they work fine, but it seems like when i hook up the res i loose suction??

thanks
Vance

**john** · 10-02-2009, 07:41 PM

Without the reservoir your valve will shut off everytime your vacuum drops from acceleration etc. Best to keep it or replace it at some point.

VanceH · 10-02-2009, 07:56 PM

it seems broke is there a way to test it??

10-02-2009, 03:50 PM	#1
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	New Heater Valve NO HEAT??? ok i have a 72 jimmy with A/C, i was always getting heat, so i replaced the heater shut off valve, and now i get nothing but cold air??? I thought i had it on backwards so i turned it around but still the same??? Any ideas thanks Vance

10-02-2009, 04:00 PM	#2
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	Re: New Heater Valve NO HEAT??? 2 things to check. 1 is the valve working? If not do you have good vacuum going to it? 2 Is your system full of water? WES __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

10-02-2009, 04:19 PM	#3
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: New Heater Valve NO HEAT??? Do you have the right valve? some open with vacuum others close with vaccuum. Just a thought. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

10-02-2009, 04:20 PM	#4
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? Not sure how to check if it is working?? Where is the main vacuum block for this? and plenty of water. The old one was not shuting off so i was getting hot air all the time, there is a vent under the cowl that is ran by a vacuum as well?? thanks

10-02-2009, 04:21 PM	#5
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? It was the one that LMC had?? Ihope it was the right one.

10-02-2009, 04:49 PM	#6
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: New Heater Valve NO HEAT??? Might check the source. Looks like it should heat with no vacuum to the valve. Good luck. Attached Images __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 10-02-2009 at 04:51 PM.

10-02-2009, 05:18 PM	#7
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? where is the source? and were is the control head vacuum switch, i am assumming that it is under the dash somewere???

10-02-2009, 05:46 PM	#8
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: New Heater Valve NO HEAT??? Goes from the vacuum reservoir to the backside of the a/c control on the dash. Some models have three lines on the control instead of two with a tee as shown. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

10-02-2009, 06:23 PM	#9
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? ok found the control head switch, the lever that ran it was broke, now fixed, also i found the vacuum res. it had no vacuum lines at all, i found the one from the switch, but i still dont know where the source is?? What does the vacuum source look like, is it off the carb?? Sorry for the trouble thanks Vance

10-02-2009, 07:01 PM	#10
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: New Heater Valve NO HEAT??? Vance, the source is anyplace you can find full vacuum. Ususally on the intake manifold fitting behind the carb, or off of the carb itself. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

10-02-2009, 07:03 PM	#11
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? LOL ya figured that one out, been a long day, i have it all hooked up and still not enough vacuum to open the valve, i can suck it open so i know its working, i guess ill head out and tinker some more. Thanks for all the help vance

10-02-2009, 07:18 PM	#12
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: New Heater Valve NO HEAT??? Sometimes the lines just get old and split or crack or fall off. sound like you're on the right track. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

10-02-2009, 07:22 PM	#13
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? Ok what does the vacuum resorvior actually do? can i bypass this totally, if i hook up each of the vacuum valves to the main source they work fine, but it seems like when i hook up the res i loose suction?? thanks Vance Last edited by VanceH; 10-02-2009 at 07:22 PM. Reason: spelling

10-02-2009, 07:41 PM	#14
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: New Heater Valve NO HEAT??? Without the reservoir your valve will shut off everytime your vacuum drops from acceleration etc. Best to keep it or replace it at some point. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

10-02-2009, 07:56 PM	#15
VanceH Loving the Jimmster Join Date: Jun 2008 Location: Emmett, idaho Posts: 575	Re: New Heater Valve NO HEAT??? it seems broke is there a way to test it??



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