As Elijah says, the Autotemp system on 69 and 70 Imperials is the same
(I'm not familiar with the boxcars). This system has few control system
parts under the hood -- just a vacuum operated coolant flow valve (one
hose) with a thermostatic vacuum valve (two hoses).
I've had problems with my 70 system for years and never really bothered
to do any heavy duty diagnosis. I did replace the pushbutton unit with
an NOS part (balky buttons) and I swapped in a used brain. These didn't
fix the problem. I keep meaning to check the vacuum switches on the
heater case and test each vacuum line but it's just so easy to use my
left index finger and lower all the windows!
Describe the problem you are having on your 69 and we'll take a crack at
it.
The 71-73 Autotemp II system, by comparison, has a LOT more control
stuff under the hood. The servo mechanism is quite the plumbing monster
and problematic.
As luck would have it, another list I'm on has a sponsor that TODAY ONLY
is offering the upgraded metal-bodied servo for $295 plus a refundable
$50 core charge. I gather that this is a pretty good deal for this part
but I'm glad that I don't need it :-) If you're interested go here:
<Rusty Cullens / The official parts vendor for www.mbz.org / Please
visit
<our on line parts catalogs at:
http://BuyMBparts.com
Oh, and the part number for the rear expansion valve on a 66 is 2521854.
This part also shows up in the 1965 Master Parts Catalog.
Pete in PA
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