The Stovebolt Site Forums The Shop Area Interiors Heater shutoff

I'm not sure if this is the right forum to post this on, but here goes:

I have the original (1950) heater shutoff valve. It goes through the firewall and has two tubes that connect to the incoming heater hose for the heater core. Inside the cab is a knob under the dash that says "warmer" with coresponding arrows.

What has me stumped is the wire or tube coming out of the unit. It looks like it might be a thermometer tube, but for what purpose? Does it open the valve if the heater gets too hot? And what does the loose end connect to? Does it just sit there and monitor ambient air temperature?

Thanks in advance for your help!

Craig

Here is how to attach it

...link...

Others can address its purpose and function.
Try searching Ranco valve

Here is the link from above
http://chevy.oldcarmanualproject.com/accessories/1951am/51aim37.htm

Thanks Dads50! The pictures and the link sure help. From them I figure the capillary tube fine tunes the opening of the heater valve depending on the ambient temperature in the cab.

Is there any way to test the capillary tube for proper functioning?

Craig

Word on the street is to use your freezer and a pan of hot (±130°) water. Allow a 5 - 10 minute temp soak, then watch how it affects the plunger.

Don't expect "climate control" results. Be glad that you have the cap tube. I know of no place that replaces those that are missing, judging by forum posts.

When I dug into my heater control valve guts, I noticed that the plunger stroke is hardly enough to shut off the flow through the valve...and this is independent of the capillary tube.

Bill

The second link posted is courtesy of tclederman.
He originally posted the oldcarmanual project page.
Very helpful

Here is another discussion on the tube
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=709231&page=1

Back in the 70's when my Dad was driving the 50, the heater always worked when we needed it. The tube had been missing from the valve for years.

Sounds like the test method suggested above should work.

Good Luck

My Dad's 52 is also missing the control tube/valve with capillary tube - Apparently now I know it heater was always on with coolant recirculating through the heater core. Thanks to all for the pics and references.

About ten years ago, I picked up a valve at a junk yard. I sent it off to Chevy Duty (now Classic Parts) to have it rebuilt. I had no idea there was supposed to be a capillary tube until they called to tell me that it was missing. They were able to reattach one and fix it up quite nicely. I don't know if they still offer this service, though.