jsup wrote:
To be clear, the valve is before the input to the heater core. If you feel the hoses and it's a different temp, only proves the heater core is clogged, nothing about the heater control valve.

You have to feel the hoses on each side of the valve, not of the core.

Actually, only touch the output side of the HCV and see if it warms up.

I'm 99% sure that will be the problem. Either the valve or the control for it. Like I said, for the winter bypass it and deal with it in the spring.

If it's the valve, it's easy, if it's the control, it's more complicated. Don't know if it's electrical or vacuum activated.