wanted heater valve for Cadillac

I would like to change my heater valve out on my Criterion to see if that will produce heat. Anyone got one cheap?

TKS

:thumbsup:

The less expensive method to checking the valve is to see if the water is hot on one side of the valve, and cold on the other side. If you want to go to the effort to change the valve, then just replace it with a mechanical valve from NAPA or Carquest. You can still find the original vacuum controlled valves on ebay, but they are usually very expensive. The replacement mechanical valves at Carquest are under $20 and are very easy to install. My 1969 Miller Meteor ambulance has a cable controlled mechanical valve for regulating the hot water to the rear heater. It appears to be originally installed when the vehicle was new.

Paul Steinberg said:

The less expensive method to checking the valve is to see if the water is hot on one side of the valve, and cold on the other side. If you want to go to the effort to change the valve, then just replace it with a mechanical valve from NAPA or Carquest. You can still find the original vacuum controlled valves on ebay, but they are usually very expensive. The replacement mechanical valves at Carquest are under $20 and are very easy to install. My 1969 Miller Meteor ambulance has a cable controlled mechanical valve for regulating the hot water to the rear heater. It appears to be originally installed when the vehicle was new.

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You are correct on all points here Paul. I have bought an original type on ebay and usually they are expensive and your 69 was fixed with rear cable from the factory.

now check the book the water valve on the caddy is normally open. it is vacuum closed only during the max ac cycle. it should be hot going in and coming out. they are not a expensive valve. you can pay a lot for then if you choose but the last one I got for my 73 at Carquest was for me 24 bucks.
as you don't have AC. hooking the hose direct and bypassing the valve would give you the water flow. that is if yours is bad. remember it is designed to shut the water off for max AC not control the water temp for the heater. temp is controlled but a mix of fresh air and hot air and AC. getting heat out of the system should be the least of your problems. roll the temp wheel to the most warm position set it to auto and the fan should come on on high. hot air out of the floor. as you dial it back down the fan should slow down in speed till you get to the cool side and then it will increase and blow out of the dash vents cool air. if it is doing that you system is working. the system is not instant on and off but takes time to cycle as you move the dial but it should respond timely. if the fan is not working there is a high relay and a low relay. most also have a thermal delay switch. that will not let the fan be powered until the water temp closes the thermal switch. this one is a lot of time the thing that is out or the wires are corroded so that it will not function. so to get the fan to work at any speed there are at least 3 sets of switches that must be wired and working plus the resister coils. first test in the system is the blower motor it's self. jump it to make sure it will work. then go to the thermal switch and make sure you have power going in and out when the engine is at normal temp. then the relays. the default test is the defroster mode you should have high fan in that mode. if the high relay is out you should have low fan in the vent mode fan speed set at low. hot water in and out and the fan blows you should get heat out of the system AC hooked up or not. if you don't have heat in and out then remove the valve and make sure it's not plugged. then back flush the heater block with the garden hose. big pipe in, little out or bottom in top out. you got hot water going threw the heater core and the blower works. still no heat then its a vacuum problem. no vacuum going into the control or none going out. a line off the servo or pinched off before it gets there. cracked or broken hoses are usually on the engine side. pinched or off were you have added something inside. there are a number of working parts to this system. you need the book and the ability to understand what is not and what is working. but if the control unit is not working you should still get some heat out of it. it will come and go with no control except defrost. just ask Robert. they did not want any cold caddies. so set the system to put out heat if the controller goes bad. if you got nothing you got other problems. most likely electrical in nature. most likely something under the hood.

If I were to install a valve and turn the water on manually, that would mean I would have heat on all the way right? I will check this weekend when I get the Criterion out to play with.

Richard Vyse said:

If I were to install a valve and turn the water on manually, that would mean I would have heat on all the way right? I will check this weekend when I get the Criterion out to play with.

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no listen to what I have said. the valve is "open" that is "open" all the time. the only time it will close is when you set the control inside the car for max air. you should have water flowing all the time except on max air. if you think it is not working take it off. run the heater hose right into the heater. but if you have a hot hose going in and a hot hose coming, out the valve is open leave it alone. set the inside control to 85. the fan should now come on and you should have hot air coming out of the floor. if not, it's not the water valve's fault. look else were for a different problem. the mistake that is made is to have the control on say 70 deg. with sun light shinning in. the inside tem may be 70 deg at the temp sensing unit passengers side dash. the controller then shuts down the fan as it at temp on the inside. if it's warmer then 70 at the sensor then it closes the heater off and adds more outside air to try to bring it back down. it does that threw the dash vents. if it still won't come down it will kick the compressor on to bring it down to temp. keeping the heater damper off. so say you got hot water flowing threw the heater and the fan will run at all speeds. but you still have nothing but cold air at the floor or other vents. it's a vacuum problem. if you have good vacuum going into the control unit. you then check the door operation. one may be jammed or the servo not working. but 9 times out of 10 it's one of the splices that have broken. as caddy was big at putting them right behind the brake pedal some big footed guy may have kicked them apart. does the vacuum pull off for the park brake work? same main line. most people run out and buy the new 50 to 75 dollar heater control valve because it does not shut off the water flow. then when the new valve does not shut off the water flow either they blame the inside controller as being bad. both are working as they should. it is just the vacuum hose that is split and sucking air. the first thing is you have to understand is the system and how it is engineered to work. it may be built different then you think. I have learned the hard way the water valve is. I have also learned that the Oldsmobile system and the caddy system work differently to achieve the same results. you must get a book

John ED Renstrom said:

no listen to what I have said. the valve is "open" that is "open" all the time. the only time it will close is when you set the control inside the car for max air. you should have water flowing all the time except on max air. if you think it is not working take it off. run the heater hose right into the heater. but if you have a hot hose going in and a hot hose coming, out the valve is open leave it alone. set the inside control to 85. the fan should now come on and you should have hot air coming out of the floor. if not, it's not the water valve's fault. look else were for a different problem. the mistake that is made is to have the control on say 70 deg. with sun light shinning in. the inside tem may be 70 deg at the temp sensing unit passengers side dash. the controller then shuts down the fan as it at temp on the inside. if it's warmer then 70 at the sensor then it closes the heater off and adds more outside air to try to bring it back down. it does that threw the dash vents. if it still won't come down it will kick the compressor on to bring it down to temp. keeping the heater damper off. so say you got hot water flowing threw the heater and the fan will run at all speeds. but you still have nothing but cold air at the floor or other vents. it's a vacuum problem. if you have good vacuum going into the control unit. you then check the door operation. one may be jammed or the servo not working. but 9 times out of 10 it's one of the splices that have broken. as caddy was big at putting them right behind the brake pedal some big footed guy may have kicked them apart. does the vacuum pull off for the park brake work? same main line. most people run out and buy the new 50 to 75 dollar heater control valve because it does not shut off the water flow. then when the new valve does not shut off the water flow either they blame the inside controller as being bad. both are working as they should. it is just the vacuum hose that is split and sucking air. the first thing is you have to understand is the system and how it is engineered to work. it may be built different then you think. I have learned the hard way the water valve is. I have also learned that the Oldsmobile system and the caddy system work differently to achieve the same results. you must get a book

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I checked it today and I have hot water going to the valve and coming away from the valve but very little heat inside. Matter of fact I thought at first I was getting heat, at least it felt that way, then it sorta went cold again. I was excited to see the compressor did come on when moving it to a colder setting but did not get cold A/C air. I tried the rear heat too but only got cold air. I ordered a climate controller today from eBay (GTD to work) which I will use on the Lifeliner. When I get time I will trace the vacuum lines like suggested for leaks.
Thanks for everyone's help.
PS: This is under Terri's name since I forgot to sign in and hate to re-type all this again. :bonk:

did you try to back flush the heater core. the water could be flow threw just one side enough to give you heat out but not enough to warm up the core enough to transfer heat. or it has a air lock. a quick check for the flow rate is to take the cap off when it's cold start then car and looking down in the radiator rev the engine you should be able to see the return flow going back into the radiator it should be a good stream. but you could be looking at return flow from the rear also. to check take a long nose vice grips and pinch off the return from the rear. you don't have to run it till it's warm to check the flow remember the vale is normally open. as for the back heater is the valve open to it? they put a screw valve on a lot of them. the handle would fall off and it is hard to tell if it is open or closed. again are both hoses hot? if you going to back flush the cab heater do the back one also but do them separately. I take it from your post that the fan is working. if the controller will switch to defrost and the park brake comes off when you put it in gear you have vacuum. when we talk about hot going in and out we are referring to normal operating temp. 180 deg should be uncomfortable to hold tight more then a few seconds. I can't say how to test the temp senser. the book for the 73 is out in the 73 somewere. I know I scaned the page for the test and sent them to Josh once but I must not have save them as I can't find then in this box. you need to know the controler is bad before you change it. if you get it changed and it still dosen't work you have no ida what is wrong

OK here are a few pages from the book. there are two sensors one for out side air and one for the inside air. but it reads to me you have a vacuum problem,

and one more. this book is not as clear as the oldsmobile one is but it still has all the info you need. first test is the water flow

Thanks Ed, invaluable information. I will do come additional checking when I can get the Criterion out for the day.