How To Replace Heater Control Valve?
07-06-2006, 12:54 AM
#1
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How To Replace Heater Control Valve?
SO, who has replaced their heater control valve? What is the most efficient way to get down to it? Must all of the grounds and wires come off first? Will it require removing the intake manifold?
Mine blew the other night because I got in a hurry and didn't bleed the cooling system quite enough. So who has the best method? Thanks,
E
Mine blew the other night because I got in a hurry and didn't bleed the cooling system quite enough. So who has the best method? Thanks,
E
07-06-2006, 12:58 AM
#2
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Carefully. LOL
Be really really careful back there, as the firewall is sharp as all get out. With the number of bolts that hold the intake on, I would take that off. I didn't need to disconnect any of the grounds when I replaced mine when I did my head gasket in 2003.
Be really really careful back there, as the firewall is sharp as all get out. With the number of bolts that hold the intake on, I would take that off. I didn't need to disconnect any of the grounds when I replaced mine when I did my head gasket in 2003.
07-06-2006, 01:17 AM
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Hmm, so it'spossible to remove it without screwing around with the wires. Did you replace the intake manifold gaskets when you put it back on? remember any other issues with the job?
07-06-2006, 04:06 AM
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lol. Umm I should be able to skip the coolant drain part. I'll just move on to the cursing and such. 
thanks for the replies guys.
E
thanks for the replies guys.
E
07-07-2006, 05:10 PM
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Hmmm. I've changed it on my 83 944 and it was a major PITA but doable by sitting on the front shock tower and squeezing my hands back in between the firewall and the back of the block. You need to remove the flywheel sensor bracket and be VERY careful not to damage the connectors or you'll have collateral damage and end up replacing a $125 flywheel sensor like I did. 
OTOH, replacement on the 944S2 was a piece of cake, since it sits right below the distributor cap.
Haven't checked my 951 but was under the impression it would have been rerouted to the front, like on the S2 since I have a 1991 MY.
What year is your car, ehall? FWIW here's a write-up I did in the E-mail lists back in March 2002 on the subject if it helps you any.
__________________
OTOH, replacement on the 944S2 was a piece of cake, since it sits right below the distributor cap.
Haven't checked my 951 but was under the impression it would have been rerouted to the front, like on the S2 since I have a 1991 MY.
What year is your car, ehall? FWIW here's a write-up I did in the E-mail lists back in March 2002 on the subject if it helps you any.
Tue, 12 Mar 2002 08:10:43 -0500
Author: "Luis de Prat" <ldep@earthlink.net>
Subject: Heater control valve replacement (Long)
Body:
Yesterday was a day of much uncertainty in the solitary island life of this stubborn bachelor intent on relying on a 19 year-old vehicle as a
daily driver against all odds. After identifying the heater control valve as the likely culprit of my white smoking incident the other day, I was
reluctant to attempt the 12 mile drive to the office until I was able to locate and replace the HCV. As mentioned in an earlier post, I was able to find one locally and called the office to say I was having car trouble and working on resolving the problem.
Before attempting the repair, I received some helpful E-mails from Steve Petty and other listers and also browsed the archives for any additional hints. Since I had the part, I thought I'd be able to complete the repair in an hour or so and get myself to the office around mid morning. Boy was I wrong. The lesson learned here is that when you're a pencil pusher mechanic such as myself and the car you're attempting to repair is 19 years old, ANYTHING can happen, as I would find out yesterday.
Heater Control Valve Replacement
I'm posting the actual heater control valve replacement procedure in case anyone with an early car needs to do it, as I couldn't find it outlined step by step in the archives.
The heater control valve (HCV) sits behind the engine block and is a disc-shaped plastic part that sits between two hoses which are clamped to the respective inlet and outlet fittings on the valve. The fitting closest to the engine block, attaches in turn to the small ell shaped hose that burst on my particular car, causing the white smoke and head gasket scare.
Once you have located the valve, you're going to need to make some room for yourself to access it more easily and remove it. I found it helpful to remove the oil cap and stuff the tube with a plastic grocery bag. I also unbolted the engine grounding strap where it attaches to the firewall, and unbolted the sensor bracket with the speed/reference sensors that attaches to the block as well. This pretty much gave me enough working space to reach the hose clamps on the valve itself.
Before unclamping any hoses, I stuffed a small rag into the inspection hole on the clutch bellhousing, to prevent lost coolant from seeping into the clutch. It also provided a handy landing spot to catch the elusive cable clip on the bad HCV...
I undid the clamps on the ell hose and removed it. Then I loosened the top clamp on the HCV. This allowed me to pull the valve upwards to access the harder to reach lower clamp with a moderately long flat head screwdriver. I found it helpful to sit on the passenger side strut tower while doing this.
Once the clamps were all loosened, I thought I was all set to pull the valve out but remembered the darned cable and associated clip. This clip was the trickiest part of the repair. Before attempting to remove it, I found it helpful to look at the replacement part carefully. To remove and replace the clip I couldn't really see what was in there, but rather felt it with my fingers and intuitively got it right.
To do this, I approached the valve from the driver's side of the car and slid the temperature lever on the console (temp controls inside the car) back and forth until I could see where the cable actually attached to the valve. It basically attached at two points. First, the actual wire hooked to the white tab on the valve, and second, the cable was secured to a black plastic bracket on the valve by the hard to reach metal clip.
After sliding the console temperature lever back and forth to where the metal clip is visible, I placed my fingers beneath the plastic bracket and pushed the clip upwards taking care to catch it in my hand once the cable was released from the valve. I then slid the temperature lever around some more until the white tab became accessible and unhooked the wire, finally removing the HCV.
To replace the valve, I hooked the wire to the white tab and slid the temperature lever around yet again until the cable bracket was visible. That was when it helped to stop and study the old valve to figure out how the weird metal clip attached to the bracket.
The clip had to be inserted into a hole in the bracket on the new valve taking care to hold it from beneath with my right hand so it wouldn't fall out. There wasn't a lot of room, so while holding the clip I used my fingers to bring the cable to it and clamp it down. After several tries, it finally came together and caught. At one point the clip fell out and was thankfully caught in the rag I had stuffed in the clutch hole.
Once the cable was attached to the valve, I redid all the hoses and clamps and was done with the HCV replacement.
Author: "Luis de Prat" <ldep@earthlink.net>
Subject: Heater control valve replacement (Long)
Body:
Yesterday was a day of much uncertainty in the solitary island life of this stubborn bachelor intent on relying on a 19 year-old vehicle as a
daily driver against all odds. After identifying the heater control valve as the likely culprit of my white smoking incident the other day, I was
reluctant to attempt the 12 mile drive to the office until I was able to locate and replace the HCV. As mentioned in an earlier post, I was able to find one locally and called the office to say I was having car trouble and working on resolving the problem.
Before attempting the repair, I received some helpful E-mails from Steve Petty and other listers and also browsed the archives for any additional hints. Since I had the part, I thought I'd be able to complete the repair in an hour or so and get myself to the office around mid morning. Boy was I wrong. The lesson learned here is that when you're a pencil pusher mechanic such as myself and the car you're attempting to repair is 19 years old, ANYTHING can happen, as I would find out yesterday.
Heater Control Valve Replacement
I'm posting the actual heater control valve replacement procedure in case anyone with an early car needs to do it, as I couldn't find it outlined step by step in the archives.
The heater control valve (HCV) sits behind the engine block and is a disc-shaped plastic part that sits between two hoses which are clamped to the respective inlet and outlet fittings on the valve. The fitting closest to the engine block, attaches in turn to the small ell shaped hose that burst on my particular car, causing the white smoke and head gasket scare.
Once you have located the valve, you're going to need to make some room for yourself to access it more easily and remove it. I found it helpful to remove the oil cap and stuff the tube with a plastic grocery bag. I also unbolted the engine grounding strap where it attaches to the firewall, and unbolted the sensor bracket with the speed/reference sensors that attaches to the block as well. This pretty much gave me enough working space to reach the hose clamps on the valve itself.
Before unclamping any hoses, I stuffed a small rag into the inspection hole on the clutch bellhousing, to prevent lost coolant from seeping into the clutch. It also provided a handy landing spot to catch the elusive cable clip on the bad HCV...
I undid the clamps on the ell hose and removed it. Then I loosened the top clamp on the HCV. This allowed me to pull the valve upwards to access the harder to reach lower clamp with a moderately long flat head screwdriver. I found it helpful to sit on the passenger side strut tower while doing this.
Once the clamps were all loosened, I thought I was all set to pull the valve out but remembered the darned cable and associated clip. This clip was the trickiest part of the repair. Before attempting to remove it, I found it helpful to look at the replacement part carefully. To remove and replace the clip I couldn't really see what was in there, but rather felt it with my fingers and intuitively got it right.
To do this, I approached the valve from the driver's side of the car and slid the temperature lever on the console (temp controls inside the car) back and forth until I could see where the cable actually attached to the valve. It basically attached at two points. First, the actual wire hooked to the white tab on the valve, and second, the cable was secured to a black plastic bracket on the valve by the hard to reach metal clip.
After sliding the console temperature lever back and forth to where the metal clip is visible, I placed my fingers beneath the plastic bracket and pushed the clip upwards taking care to catch it in my hand once the cable was released from the valve. I then slid the temperature lever around some more until the white tab became accessible and unhooked the wire, finally removing the HCV.
To replace the valve, I hooked the wire to the white tab and slid the temperature lever around yet again until the cable bracket was visible. That was when it helped to stop and study the old valve to figure out how the weird metal clip attached to the bracket.
The clip had to be inserted into a hole in the bracket on the new valve taking care to hold it from beneath with my right hand so it wouldn't fall out. There wasn't a lot of room, so while holding the clip I used my fingers to bring the cable to it and clamp it down. After several tries, it finally came together and caught. At one point the clip fell out and was thankfully caught in the rag I had stuffed in the clutch hole.
Once the cable was attached to the valve, I redid all the hoses and clamps and was done with the HCV replacement.
Last edited by Luis de Prat; 07-07-2006 at 05:44 PM.
07-08-2006, 02:13 AM
#7
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Put a piece of duct tape over the hole in the bell housing. dropping something down in there will ruin what should be a simple job. When I did mine I removed the intake and replaced the gaskets. I replaced both hoses while I was in there as well. Be patient and good luck !
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07-08-2006, 02:39 AM
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Originally Posted by Luis de Prat
Hmmm. I've changed it on my 83 944 and it was a major PITA but doable by sitting on the front shock tower and squeezing my hands back in between the firewall and the back of the block. You need to remove the flywheel sensor bracket and be VERY careful not to damage the connectors or you'll have collateral damage and end up replacing a $125 flywheel sensor like I did.
OTOH, replacement on the 944S2 was a piece of cake, since it sits right below the distributor cap.
Haven't checked my 951 but was under the impression it would have been rerouted to the front, like on the S2 since I have a 1991 MY.
What year is your car, ehall? FWIW here's a write-up I did in the E-mail lists back in March 2002 on the subject if it helps you any.
__________________
OTOH, replacement on the 944S2 was a piece of cake, since it sits right below the distributor cap.
Haven't checked my 951 but was under the impression it would have been rerouted to the front, like on the S2 since I have a 1991 MY.
What year is your car, ehall? FWIW here's a write-up I did in the E-mail lists back in March 2002 on the subject if it helps you any.
__________________
