What is this? Coolant leak.
Welcome to the forum
Called the Heater control valve, or heater bypass valve
But it doesn't actually control the heat, lol
It's an on/off valve that shuts off hot coolant flow thru the heater core in the cab
It is only active(has vacuum) when MAX AC is selected in the cab
Yes, the plastic cracks and these leak
Many just replace these with 2 couplers, so no valve, the 2 heater hoses just go from engine to firewall(heater core)
Called the Heater control valve, or heater bypass valve
But it doesn't actually control the heat, lol
It's an on/off valve that shuts off hot coolant flow thru the heater core in the cab
It is only active(has vacuum) when MAX AC is selected in the cab
Yes, the plastic cracks and these leak
Many just replace these with 2 couplers, so no valve, the 2 heater hoses just go from engine to firewall(heater core)
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Joined: Mar 2020
Posts: 850
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From: US
Yep, after 10~15years that plastic junk gets brittle & cracks.
While replacing this valve is the time to replace+reverse the HeaterHoses+Clamps
(assuming they're also more than a few years old, though they look like they've been recently replaced),
give the HeaterCore a good Foreward+Backward flush with the garden hose,
& renew any other aged Hoses+Clamps plus the Coolant.
While replacing this valve is the time to replace+reverse the HeaterHoses+Clamps
(assuming they're also more than a few years old, though they look like they've been recently replaced),
give the HeaterCore a good Foreward+Backward flush with the garden hose,
& renew any other aged Hoses+Clamps plus the Coolant.
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