Heater Control Valve Problem Leak - The 1947 - Present Chevrolet & GMC Truck Message Board Network

demi · 08-09-2015, 03:22 PM

Hi folks

Can the heater control valve leak only during full acceleration?

It seams that mine is spraying coolant. There are no visible leaks around the hoses or the valve itself when running or after shut off. The only thing I did last nite was get on it once and buried the speedo (little stop light race) This morning I noticed coolant mist on the passenger inner fender cover and beneath the hood on that side. When I drive at highway speeds and normal acceleration there is no visible evidence of coolant.

Vacuum was applied shutting off the coolant flow to the heater core per the a/c lever in the cab. The valve is 10 years old so a replacement is probably necessary. I've never encountered this before.

Thanks

brad_man_72 · 08-09-2015, 09:26 PM

Radiator vent hose could be blowing excess coollant out of the radiator. A pressure test may find your leak.

demi · 08-09-2015, 11:53 PM

I'm running a closed system with the overflow bottle on the driver's side.

08-09-2015, 03:22 PM	#1
demi Registered User Join Date: Sep 2003 Location: Arizona Posts: 305	Heater Control Valve Problem Leak Hi folks Can the heater control valve leak only during full acceleration? It seams that mine is spraying coolant. There are no visible leaks around the hoses or the valve itself when running or after shut off. The only thing I did last nite was get on it once and buried the speedo (little stop light race) This morning I noticed coolant mist on the passenger inner fender cover and beneath the hood on that side. When I drive at highway speeds and normal acceleration there is no visible evidence of coolant. Vacuum was applied shutting off the coolant flow to the heater core per the a/c lever in the cab. The valve is 10 years old so a replacement is probably necessary. I've never encountered this before. Thanks

08-09-2015, 09:26 PM	#2
brad_man_72 the boat guy Join Date: Jul 2007 Location: springfield mo Posts: 2,339	Re: Heater Control Valve Problem Leak Radiator vent hose could be blowing excess coollant out of the radiator. A pressure test may find your leak. __________________ 67, swb, fleet, tach, throttle, 5.3, 4l60e, 3.73's, fuel cell, 5 lug, p.d.b., 4-6 drop. great little truck 66, stevens drag/ski 18' silouette, 350, 2.02 doublehump heads. comp extreme marine 278 cam, vette 7 fin valve covers, old polished edelbrock intake, velvetdrive, casale v-drive, adj cavitation plate. 28, model a rpu project,

08-09-2015, 11:53 PM	#3
demi Registered User Join Date: Sep 2003 Location: Arizona Posts: 305	Re: Heater Control Valve Problem Leak I'm running a closed system with the overflow bottle on the driver's side. Last edited by demi; 08-09-2015 at 11:55 PM. Reason: more info

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