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Guest Anonymous

heater valve replacement-12v soleniod from Mcmaster...

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Guest Anonymous

....think it will work? It was about $34. It's a normally closed,

12 volt valve-draws about an amp. Should work well off a

push button-eliminates the leaky valve, stuck cable routine.

I'll let y'all know how it works.

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Guest Anonymous

let us know progress please

thanks for jumpin in,

b

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Guest Anonymous

Bob,

If you want to get even more creative, rig up a circuit with a thermistor or other temperature sensor and build a set the temp and forget it circuit. Like the modern rigs have. My other Bimmer has one of those and I sure miss it when I'm driving something else.

You could probably find an electronic thermometer somewhere that we could hack into.

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Guest Anonymous

....that was my next step. It's a no brainer to hook up a

thermostat to a solenoid. It would simply open and close on

demand rather than limit flow like the oem valve does-great

minds think alike:).

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Guest Anonymous

That's going to blow hot then cold depending on the state of the valve. What you need is proportional control. Or do what BMW does in E28 (and probably newer) vehicles. Run a square wave to the solenoid (don't know the frequency) varying the duty cycle in order to make the heater core warmer or colder as needed.

Do you think you could partially open the valve using a trick like that? Or would it be totally open or closed all the time, but with a duty cycle that controls the resulting heater core exit temperature as needed?

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Guest Anonymous

between! It's a lot easier to lubricate the valve and use it periodically during the summer to keep it freed up. Also, the same control works the cold air mixer door, so to control heat you'll have to energize the solenoid and still move the old control lever....02s are simple, keep 'em that way ;-) IMHO

Mike

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Guest Anonymous

.....keep it simple-the simpler the better! A 12 volt solenoid is

a simple as it gets. As you noted-maybe too simple. It's either

on or off. No in between. However, if one controls the

solenoid with a thermostat-another very simple device, it will

act much as a forced air heating system in a building works-

it's either on or off. What controls heat is how often it's on or

off. Maybe impractical in the close confines of a passenger

vehicle, but we'll see. The real reason I'm doing it is to

eliminate what I consider a flaw-the 2002 heating valve. They

are notorious for leaking. How many floor pans have rotted

as a result of them? Hopefully, a modern solenoid won't be

as leak prone.

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Guest Anonymous

Square wave? You are operating waaay over my head. But,

it does sound intriguing and I'm all ears. But, how does one

generate a frequency in this application?

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