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I have the AIM and service manual for my ‘77, I can’t find anywhere what this is to the right of the EFE actuator and where the hose is suppose to attach, I would appreciate any help with this and where to find this in the AIM or service manual, thanks
You will find the drawing on page 142 for a A/C optioned car.
UPC B01 To B12 Sheet 71 item 12 on the parts list...
That is a replacement shutoff valve so it will look different then what is on the drawing.
Me thinks, that unconnected hose is dead & the one on the valve now is just replacing it ...
I found the drawing, yes it looks different, the unconnected hose is the one on the valve, I have attached a better picture, where does that hose attach?
The input to the hot water shut-off valve is a heater hose that comes from the intake manifold. The outlet is a heater hose that runs down and connects to one of the heater core tubes. Look under your car and you can see the connections.
There is also a small vacuum hose that attaches to the valve that runs through the firewall and connects to your HVAC controller on your console. The "Temp" lever controls the opening (Hot) and closing (Cold) of the valve. That is the curled up hose setting on your exhaust manifold in the second pic.
As to the large hose that appears connected to nothing, there are two possible hoses that come to mind.
1) It might be the hose that once went to an AIR (smog) pump. In 1977, Chevrolet only installed those on L82 engines or any region of the country that was high altitude or local regulations required such smog equipment, such as California.
2) It was once an A/C hose.
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1979 L82 M21 FE7
Classic White / Doeskin
I found the drawing, yes it looks different, the unconnected hose is the one on the valve, I have attached a better picture, where does that hose attach?
You're showing the vacuum line that enters the firewall, (and in this case...doesn't) connecting to the climate control apparatus. Someone disconnected it. I give a shout out to the 1975-77 NCRS TIMJG (technical manual that was updated just a few years ago. and details many of these vacuum issues that continuously get asked on the forum.
This is the page that explains the water-shut off connection
The drawing on post #4 shows a 3 hole rubber grommet.
One of those holes you might find a broken off 1/8" O.D. piece of poly type tubing?
1/16" I.D. X 1/8" O.D. tubing was used.
Problem is, these grommets were molded to the tubing.
Now you can cut off the molded section where the broken tubing is on the grommet and enlarge the hole so a piece of regular 1/8" I.D. rubber vacuum hose can pass through the grommet...
If you follow on post #4 drawing after the firewall that White poly tubing land at the Vacuum Operated Water Shutoff Switch that is on top of the heater box..
Here is a photo of the 3 hole grommet...
You're showing the vacuum line that enters the firewall, (and in this case...doesn't) connecting to the climate control apparatus. Someone disconnected it. I give a shout out to the 1975-77 NCRS TIMJG (technical manual that was updated just a few years ago. and details many of these vacuum issues that continuously get asked on the forum.
This is the page that explains the water-shut off connection
Good Info!
Did you know these valves were made by the RANCO Company out of Columbus Ohio?
GM #495613 was RANCO model number H25-118 and were also date coded...
These valves were also repackaged and sold under the Robert Shaw brand...
Thanks to all of you for your input, both pictures are of the same hose, I just curled up the hose in the 2nd photo to make it easier to see my issue, now I just have to find the 3 hole grommet.
Last edited by HarleyBrian; Dec 20, 2024 at 10:22 AM.
Good Info!
Did you know these valves were made by the RANCO Company out of Columbus Ohio?
GM #495613 was RANCO model number H25-118 and were also date coded...
These valves were also repackaged and sold under the Robert Shaw brand...
Great stuff!
I'm thinking the date code is the 77 42? 42nd day of 1977? Do you recall when you squirreled that part away?
Engine Compartment
