Topic: Flush or No Flush?
in Forum: C3 Cooling and Heating Systems
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You really have no need to drain coolant to close valves. I would make sure you have fresh coolant in the system, and the rust inhibitors will protect the core. After all summer weather in Chicago only lasts 1-2 months, right?

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Chicago, IL - USA
Joined: 11/30/2007
Posts: 37
Vette(s): 1976 L48 T-top, Automatic, ps,pb,a/c, Everything stock. Good car in great shape.
Exactly!! Actually, it seems like the warm weather gets longer in the fall, but the cold stuffstays around longer in the spring...really weird.
Tanks for all your help.
I'm gonna try to replace the vacuumcontrol valve with the manual ne either tonight or tomorrow to see if that was the flow inhibitor. If that's not the cuprit, then I guess I'm stumped. I haven't been able to trace the hoses to the heater core pipes as they are under the car and I don't have a way of getting under there. Can I take off the lower dash to see hem?
Former Member
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Chicago, IL - USA
Joined: 11/30/2007
Posts: 37
Vette(s): 1976 L48 T-top, Automatic, ps,pb,a/c, Everything stock. Good car in great shape.
So I replaced the old vacuum valve with a manual one and now I have heat! Thanks to everyone that helped...
In the spring, I will attack the other valve so I can shut it down for summer running.
I wasn't prepared for the amount of fluid that came out of the heater core when I took out the old valve. Was I supposed to drain the radiator before I took it out? Just curious as I will have to cut the other line when I do the next valve...
Thanks again!!!

Poquoson, VA - USA
Joined: 11/20/2004
Posts: 1023
Vette(s): 73 Conv, Blue-Green/White Top - 454, M21 - Dark Saddle Leather, Power Windows, A/C, Tilt/Tele, AM/FM St. (orig. and sounds like it too).#2 -- 2007 Coupe,3 LT package, Z51 option, Victory Red, Ebony Int. Clear Top.
[QUOTE=1976VetteGuy]So I replaced the old vacuum valve with a manual one and now I have heat! Thanks to everyone that helped...
[/QUOTE]
In the spring, I will attack the other valve so I can shut it down for summer running.
I wasn't prepared for the amount of fluid that came out of the heater core when I took out the old valve. Was I supposed to drain the radiator before I took it out? Just curious as I will have to cut the other line when I do the next valve...
Thanks again!!!
Draining down to a level below where you cut will help. If you have a drain in the radiator .. great... you can do it there. Try to keep the open hose as high as possible to keep it from draining... If you need to drain it some... I usually break the line at the water pump since it makes the least mess. And easier to clean up. Unfortunately it will be somewhat messy... so do all your under-car stuff before you break the line... I would not break a "radiator" hose unless you plan on replacing it. It's a lot cheaper and easier to replace heater hose. Also leave the radiator cap on unless you want to speed up the draining.

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USN 1966-1970
WestPac 67-68 Tet I&II
Featured in Corvette Enthusiast Aug 2007 "Shark Attack"
Blue Green *** 454,4 Spd, Dark Saddle Leather, A/C, AM-FM St. (orig), PW, Tilt -Tele Wheel"

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in Forum: C3 Cooling and Heating Systems
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