C3 Overheating on the road
Thread Starter
7th Gear
Joined: Mar 2014
Posts: 7
Likes: 0
C3 Overheating on the road
I have a 78 small block with Alum. Rad.and two electric fans, 180 deg. therm., raped headers good air dam. In the cool weather there is no problem. The problem starts when the outside temp. starts to get above 80 deg. At a idle everything is ok but when I get to 65+ mph the temp starts to climb.(210+) Slow back down and temp. drops. I looked at another C3 and under the bottom air holes,behind the air dam and in front of the radiator there was a rolled looking air ramp that directed the air to the radiator. Mine does not have this. What do you call it and where can I get one?:
Pro
Joined: Oct 2009
Posts: 664
Likes: 89
From: Marysville Ohio
Sounds like you need the lower front valance and/or air dam - you should be able to find that at any of the corvette parts houses (Ecklers, Keen's, etc.). If you have an AIM, it will help you determine exactly what part or parts are missing.
Keen Parts (a forum vendor listed below in "parts" section) has AIM illustrations for reference on their website - Before I bought my own copy of the AIM, I found that useful in figuring our what was missing or what to call some things.
Keen Parts (a forum vendor listed below in "parts" section) has AIM illustrations for reference on their website - Before I bought my own copy of the AIM, I found that useful in figuring our what was missing or what to call some things.
Drifting
Joined: Oct 2005
Posts: 1,528
Likes: 148
From: East London/SW Essex UK
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
The lower air dam and all the seals around the radiator support need to be in place. You need to force the onrushing air through the radiator, and not let any go around it. That will fix most, if not all, of your problem.
Then check the fan clutch.
Then check the fan clutch.
Safety Car
Joined: Nov 2008
Posts: 3,722
Likes: 557
From: Seattle Washington
Just to ask a stupid question but have You checked the Flow direction of the Fans ? When stopped it wouldn't matter which way the Air is passing threw the Radiator but when at speed it would be a battle between the fans and the natural flow, resulting in no flow.
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Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Another possibility: the lower (suction) radiator hose could be collapsing when on the road at elevated RPM and limiting water flow. With engine OFF, see how far you can squeeze that hose. There should be a steel spring inside the hose to prevent collapse. But, they rust to nothing after some years. And, some folks don't even know to install them when changing that hose (new hoses DO NOT come with the spring, unless purchased separately).
Thread Starter
7th Gear
Joined: Mar 2014
Posts: 7
Likes: 0
Good response! Yes they are turning correct. Thanks!
Thread Starter
7th Gear
Joined: Mar 2014
Posts: 7
Likes: 0
Another possibility: the lower (suction) radiator hose could be collapsing when on the road at elevated RPM and limiting water flow. With engine OFF, see how far you can squeeze that hose. There should be a steel spring inside the hose to prevent collapse. But, they rust to nothing after some years. And, some folks don't even know to install them when changing that hose (new hoses DO NOT come with the spring, unless purchased separately).
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
Melting Slicks
Joined: Sep 2004
Posts: 3,227
Likes: 670
From: Northeast
I too had the temp go up on the highway but around town it was fine. Installed an extension like below and never over 200. You need more air for cooling. The pic was taken by forum member KAPSSA:
Advanced
Joined: Apr 2017
Posts: 54
Likes: 1
Hi I have a 80 and in hot weather the temp goes up to 220, in any other weather it's fine. Did you end up solving this issue and what was it
thanks
thanks
I have a 78 small block with Alum. Rad.and two electric fans, 180 deg. therm., raped headers good air dam. In the cool weather there is no problem. The problem starts when the outside temp. starts to get above 80 deg. At a idle everything is ok but when I get to 65+ mph the temp starts to climb.(210+) Slow back down and temp. drops. I looked at another C3 and under the bottom air holes,behind the air dam and in front of the radiator there was a rolled looking air ramp that directed the air to the radiator. Mine does not have this. What do you call it and where can I get one?: