Heater Control Valve Problem Leak

[demi]

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