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Topic: Overheating at over 60mph

in Forum: C3 Cooling and Heating Systems


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Overheating at over 60mph (1/10)
 7/23/16 5:34pm
Red C3
Former Member

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Chalmette, LA - USA

Vette(s):
Late 1976


Joined: 7/23/2016
Posts: 1

I have a C# with a rebuilt motor, 350 20 over W/ flat top 10to1 pistons small cam 268 I believe, and alum heads I bought of of ebay Pro MAXX I also took the scroud and fan off and installed a Dewitts alum radiator w duel electric fans seems like all the air is going under car HELP |frown|

Question: My C3 Corvette Overhearing over 60MPH

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1. Why is my car overheating over 60MPH
2. Why is my car overheating over 60MPH
3. Why is my car overheating over 60MPH

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Re: Overheating at over 60mph (2/10)
 7/23/16 9:32pm
stingrayjim jrLifetime Member
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SHELBYVILLE, TN - USA

Vette(s):
1976 L48 auto

1978 L82 4speed

1994 LT1 6speed


Joined: 7/5/2002
Posts: 3942

Could be a few things.... maybe an air bubble in the system, bad temp sender, water pump, check the electric fans and make sure they are blowing the correct way(if mounted in front of the radiator they should blow through toward the engine, if mounted on the back of radiator they should suck air through..... 

you might have to do a little more research on your car to give us some more information.



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StingrayJim
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Stingray's '76���������������������������� StingrayJr's '78���������������������������Lil Red '94

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Re: Overheating at over 60mph (3/10)
 7/24/16 8:37am
F4GaryGold Member
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Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.


Joined: 8/26/2006
Posts: 1460

Is this a poll?

With a DeWitts rad and cooling fans, you should have plenty of cooling capacity.


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Re: Overheating at over 60mph (4/10)
 7/25/16 4:50pm
danascar
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Germansville, PA - USA

Vette(s):
1974 Coupe 358ci 4 speed Black w/Medium Saddle interior w/79 custom leather seats. . 1999 C5 Convertible, 6 speed, Atomic orange, Oak interior.


Joined: 1/28/2010
Posts: 859

Is your air dam under the front bumper there?

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DanT

Re: Overheating at over 60mph (5/10)
 8/24/24 4:21pm
Dblancha79Gold Member
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Weatogue, CT - USA

Vette(s):
1979 C3 L82 383 cu in


Joined: 6/29/2015
Posts: 90

Should the air dam be opened or closed when on the highway?



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"Made to be run hard"
Simsbury, Ct.

Re: Overheating at over 60mph (6/10)
 8/25/24 12:11am
Dblancha79Gold Member
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Weatogue, CT - USA

Vette(s):
1979 C3 L82 383 cu in


Joined: 6/29/2015
Posts: 90

Not the spliter air dam. The  plastic flap door under the radiator.



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"Made to be run hard"
Simsbury, Ct.

Re: Overheating at over 60mph (7/10)
 8/25/24 10:46am
F4GaryGold Member
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Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.


Joined: 8/26/2006
Posts: 1460

Plastic flap door?



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Re: Overheating at over 60mph (8/10)
 8/25/24 1:03pm
manchestersharkLifetime Member
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Equinunk, PA - USA

Vette(s):
1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 2452

Yes, I was wondering the same thing. 



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Re: Overheating at over 60mph (9/10)
 8/26/24 3:37am
Dblancha79Gold Member
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Weatogue, CT - USA

Vette(s):
1979 C3 L82 383 cu in


Joined: 6/29/2015
Posts: 90

Never mind, senior moment. It was my 80 olds starfire that had the plastic hinged flap under the radiator.



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"Made to be run hard"
Simsbury, Ct.

Re: Overheating at over 60mph (10/10)
 8/26/24 8:08am
NorskyLifetime Member
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Burke, VT - USA

Vette(s):
SOLD - "The Toy" - '70 Convertible
SOLD - "The Beast" - '90 ZR-1 (#682)
SOLD - "Betty" - '28 Ford Model A Tudor
Still have - "BLKBRRD" - '78 Pontiac Trans Am


Joined: 1/23/2002
Posts: 7240

In the four years since this thread first appeared I hope the engine has cooled off by now...!!!   🤣



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Jim Olson 

"The Toys"...!!!  Save the Wave!

Where I've been in a Corvette...!!!

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