1983 300D turbo - Texas summer heat, high humidity.

I'm still thinking about how to maximize by AC performance. I've noticed when I make several stops, the AC takes a some time to put out really cool air when I restart.

Here's my thinking: The heater control valve is closed when 12V is applied and cuts off hot water flow to the heater core. No voltage the heater gets hot water. In max AC mode, 12V is constant to the heater control valve. If you turn the engine off, the voltage is lost and the valve opens. That must allow some convection circulation of hot water into the heater core. Restart in a few minutes and the valve closes, but the heater core is already full of heated water and decreases the AC temperature until the water in the core is cooled. Make sense?

I'm considering installing a manual valve in the hose and turning off the valve for summer so that no water can circulate to the heater control valve. Make sense?

The only downside I can think of is the water that's in the heater core will be stagnant for the summer. I don't see why that would be a problem. Thoughts?

I guess I could just leave it idling like the commercial diesels do.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386