Topic: Heater Core Bypass
in Forum: C3 Cooling and Heating Systems
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Lifetime MemberIndianapolis, IN - USA
Joined: 9/3/2006
Posts: 2429
Vette(s): Silver 1974 Convertible - L82 4 speed
Low miles (was only 8,900 when I bought it in March 2006) - Now 54K miles. Original owner bought it as an investment for son's college expenses.
2008 Jetstream Blue Convertible
Certainly, the topic of heat inside a C3 has been discussed a number of times. I know some folks have discussed the bypassing of the heater core, but I glanced around and did not find one specific post to discuss the process. So, how do I go about doing this in the best way to try to keep the heat out of the passenger area?
Thanks in advance!
I wanted a Corvette my whole life, but I never dreamed of all the wonderful people I would meet because of it!
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Lifetime MemberLemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
This
is the Link .. I did it when I replaced my heater core which was when I replaced my dash. I can provide pictures if you need or want them.
If the link does not work it is on the top of the forth page on the "C3 Cooling and Heating Systems" forum.
(inserted clickable link)
Adams' Apple 2009-06-07 12:15:00
If the link does not work it is on the top of the forth page on the "C3 Cooling and Heating Systems" forum.
Hey Marshall,
I went ahead and did that last year. All it took was new heater hoses, a five eighths & a three quarter shut off valve plus a leap of faith, which I got here.
There is some debate over the necessity of connecting the water pump hose to the 2nd. heater hose which enters the intake manifold. I didn't do that but plan on it when I can.
I'm not much of a mechanic but I was able to get it done.
Kevin
Lifetime MemberManteca, CA - USA
Joined: 11/20/2005
Posts: 3623
Vette(s): 1978,two tone,Metalic Rootbeer & gold
1975 L48 4 speed
The inline positive shutoff valves work great and it's not complicated once you drain off the coolant. Just cut in to each hose and install a valve, clamp them back on and your all set. Leave open for winter and off during the summer. I did mine down low on the hoses before they enter the fire wall so they were less noticable.
Jimmy B.
Just can't wait to get on the road again. 
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Lifetime MemberIndianapolis, IN - USA
Joined: 9/3/2006
Posts: 2429
Vette(s): Silver 1974 Convertible - L82 4 speed
Low miles (was only 8,900 when I bought it in March 2006) - Now 54K miles. Original owner bought it as an investment for son's college expenses.
2008 Jetstream Blue Convertible
You know, as common as this problem is, I'm surprised Mid America and the other vendors don't have a "package" solution. Years ago, I simply did a bypass of my heater core in my 76 Grand Prix by taking the two heater hoses and running them from one to the other with a metal fitting. Anyone done anything like that?
manget1 2009-06-07 13:55:23
Thanks everyone. I'll take a look at the links
I wanted a Corvette my whole life, but I never dreamed of all the wonderful people I would meet because of it!
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
I actually prefer to tie the two hoses together. If what you're trying to do is remove heater core heat from teh passenger compartment, it's the only way to completely eliminate heat transfer. Even with the shut-off valves in both lines, heat will still transfer from the engine-side hoses thru the valves...it's called convection heat. Just because water(coolant) is not circulating thru the core doesn't mean the heat is gone...just diminished.
Do the shut-off valves help? You betcha.
But disconnecting the hoses entirely eliminates the heat transfer completely.
It's six one way and half a dozen the other...
Do the shut-off valves help? You betcha.
But disconnecting the hoses entirely eliminates the heat transfer completely.It's six one way and half a dozen the other...
Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Lifetime MemberIndianapolis, IN - USA
Joined: 9/3/2006
Posts: 2429
Vette(s): Silver 1974 Convertible - L82 4 speed
Low miles (was only 8,900 when I bought it in March 2006) - Now 54K miles. Original owner bought it as an investment for son's college expenses.
2008 Jetstream Blue Convertible
That's exactly what I'm hoping to do Joel! Anyone know of a part out there designed for that? Back in the day, I just looked around the shop, but that was a long time ago...
I wanted a Corvette my whole life, but I never dreamed of all the wonderful people I would meet because of it!
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
One problem will be that the two hoses are different sizes...on is 5/8" id, and the other is 3/4" id. I've used 5/8" pipe, and the 3/4" hose will clamp down it it. It's a bit harder to get the 5/8" hose to stretch to fit a 3/4" pipe...
Your local hardware store will have the part you need...just don't tell them it's for a Corvette...they'll jack the price up...
Your local hardware store will have the part you need...just don't tell them it's for a Corvette...they'll jack the price up...
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
One - Thank you Marshall, I actually logged on to ask this question today. Ted and I took the Vette to Madison to see Jeff Dunham (awesome show, front row seats) and on the way home he said how can you drive in this car, it is so uncomfortable and I said it isn't cushioned that bad and he said "MY ASS IS HOT!" My car is definitely hot and not the way I want it to be. My feet burn have the time. '
Two - you guys are scaring me. Can I actually do this myself? We are talking about me, the computer geek here, not a car person.
And Joel, what is this tying hoses together, is the like having your tubes tied??? 
I am so confused. All I know is even when I use my AC the car is still hot at the feet.
I am so confused. All I know is even when I use my AC the car is still hot at the feet. Is this the valve everyone is talking about???
dsireme 2009-06-09 08:49:41
Also I had found this:
in Forum: C3 Cooling and Heating Systems
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