2004-10-13
Saga of the Heater Valve: Part 1
For the past few months, the heater control valve in my Jeep [1992, Cherokee, 4.0l, 5 spd] has had a small leak. Until a couple of weeks ago this was barely noticeable, just requiring a little topping off of the coolant when changing the oil.
Over the last couple of weeks the leak has been dripping onto the starter / starter solenoid and has become a real nuisance. While the solenoid engages with each turn of the key, it requires several tries or a blow from a hammer / the clutch before the starter will turn. I think that the coolant has contaminated some of the electrical contacts in the solenoid and/or starter.
On Monday I bought a replacement heater valve at the local Shucks auto parts store. The “Four Seasons 74777, Fact Air Heater Valve” was the only one in stock. On Tuesday I swapped out the old valve for the new one and found that the new one leaked much worse then the old one. The new valve leaked around shaft that rotates the butterfly plate where the shaft enters the housing.
TIP: When swapping out this valve place a 1-gallon plastic freezer bag stuffed with paper towels under and around the valve before you disconnect the hoses. The bag should catch the coolant that drains out of valve and the heater core.
I couldn’t leave the new valve in as it would leave a good size trail of coolant everywhere I drove and a puddle when I stopped. I couldn’t put the old one back in as it was killing my starter. Correctly figuring that it would take several days to find a better replacement, I got a lift down to Lowes and picked up a couple of brass hose butt connectors and simply bypassed the heater core.
Today returned the defective “Four Seasons” heater valve, and ordered a “Ready Aire, 5941 Heater Valve”. As expected it won’t arrive until the 18th. So until then I have no heater. Or if it gets unexpectedly cold I can swap the connectors around and have heat that is always on.
This is the third time I’ve had to replace this valve and I think that it a underlying problem is a design flaw. The OEM part and the replacements have all had plastic housings that I suspect have been cracking from the hot and cold cycling experienced in about 50k miles. So I’m also looking for a better long term solution, like a better designed valve meant for some other vehicle or some other application entirely. The valve has four hose attachments for standard 5/8” heater hoses and is actuated by a small vacuum servo.
Over the last couple of weeks the leak has been dripping onto the starter / starter solenoid and has become a real nuisance. While the solenoid engages with each turn of the key, it requires several tries or a blow from a hammer / the clutch before the starter will turn. I think that the coolant has contaminated some of the electrical contacts in the solenoid and/or starter.
On Monday I bought a replacement heater valve at the local Shucks auto parts store. The “Four Seasons 74777, Fact Air Heater Valve” was the only one in stock. On Tuesday I swapped out the old valve for the new one and found that the new one leaked much worse then the old one. The new valve leaked around shaft that rotates the butterfly plate where the shaft enters the housing.
TIP: When swapping out this valve place a 1-gallon plastic freezer bag stuffed with paper towels under and around the valve before you disconnect the hoses. The bag should catch the coolant that drains out of valve and the heater core.
I couldn’t leave the new valve in as it would leave a good size trail of coolant everywhere I drove and a puddle when I stopped. I couldn’t put the old one back in as it was killing my starter. Correctly figuring that it would take several days to find a better replacement, I got a lift down to Lowes and picked up a couple of brass hose butt connectors and simply bypassed the heater core.
Today returned the defective “Four Seasons” heater valve, and ordered a “Ready Aire, 5941 Heater Valve”. As expected it won’t arrive until the 18th. So until then I have no heater. Or if it gets unexpectedly cold I can swap the connectors around and have heat that is always on.
This is the third time I’ve had to replace this valve and I think that it a underlying problem is a design flaw. The OEM part and the replacements have all had plastic housings that I suspect have been cracking from the hot and cold cycling experienced in about 50k miles. So I’m also looking for a better long term solution, like a better designed valve meant for some other vehicle or some other application entirely. The valve has four hose attachments for standard 5/8” heater hoses and is actuated by a small vacuum servo.
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Copyright by Tom Sayles.
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