New Radiator Overheating
Thread Starter
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
New Radiator Overheating
Anyone ever put a Champion radiator in their C3?
I started a thread about this back in July. I have a newly rebuilt 350(mild). Upgraded waterpump. 185 stat. New OEM radiator (brass). After following the suggestions from the previous thread (mainly ensuring a good seal around the shroud to the radiator) it would still run to 220+ just at idle. I did confirm correct temp reading with a mechanical gauge as well as digital electronic gauge. Then I had to ignore the car until November (business stuff)!!!!! Now the car will run just warmer than normal temps with the cooler outdoor temps, duh! I'm thinking a better cooling radiator. I have heard good things about the Champion radiators available on eBay. But that's by folks who have vehicles with direct air flow to the radiator. I am curious how they will perform in a vette which pulls its cooling air flow from under the front of the car. Any thoughts. Thanks in advance!
I started a thread about this back in July. I have a newly rebuilt 350(mild). Upgraded waterpump. 185 stat. New OEM radiator (brass). After following the suggestions from the previous thread (mainly ensuring a good seal around the shroud to the radiator) it would still run to 220+ just at idle. I did confirm correct temp reading with a mechanical gauge as well as digital electronic gauge. Then I had to ignore the car until November (business stuff)!!!!! Now the car will run just warmer than normal temps with the cooler outdoor temps, duh! I'm thinking a better cooling radiator. I have heard good things about the Champion radiators available on eBay. But that's by folks who have vehicles with direct air flow to the radiator. I am curious how they will perform in a vette which pulls its cooling air flow from under the front of the car. Any thoughts. Thanks in advance!
Thread Starter
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
It's not. My temp readings com from a mechanical gauge I bought at my local race shop and a fluke digital thermometer accurate to 10th of a degree. I used both to double check or confirm the other's reading and they are within a couple degrees of each other. That difference is probably because of the different locations. The mechanical is in the head and the digital probe is inside the upper radiator hose. Either way I am comfortable I have correct temps.
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
The brass radiator should be fine for your cooling needs.
I went back and read the comments form the earlier thread, did you try any of the suggested fixes?
Did you check the fan to make sure its turning the right direction?
Did you let it warm up and than let it cool back down to see if it would pull water form the overflow tank? (checking for air in the system)
Did you check to see what the temp difference is across the radiator form inlet to outlet?
Just trying to get and idea of were your at with your testing.
Neal
I went back and read the comments form the earlier thread, did you try any of the suggested fixes?
Did you check the fan to make sure its turning the right direction?
Did you let it warm up and than let it cool back down to see if it would pull water form the overflow tank? (checking for air in the system)
Did you check to see what the temp difference is across the radiator form inlet to outlet?
Just trying to get and idea of were your at with your testing.
Neal
Thread Starter
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
The brass radiator should be fine for your cooling needs.
I went back and read the comments form the earlier thread, did you try any of the suggested fixes?
Did you check the fan to make sure its turning the right direction?
Did you let it warm up and than let it cool back down to see if it would pull water form the overflow tank? (checking for air in the system)
Did you check to see what the temp difference is across the radiator form inlet to outlet?
Just trying to get and idea of were your at with your testing.
Neal
I went back and read the comments form the earlier thread, did you try any of the suggested fixes?
Did you check the fan to make sure its turning the right direction?
Did you let it warm up and than let it cool back down to see if it would pull water form the overflow tank? (checking for air in the system)
Did you check to see what the temp difference is across the radiator form inlet to outlet?
Just trying to get and idea of were your at with your testing.
Neal
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
Its been a while since I've used a flex fan but I seem to remember that it can be bolted on either way pushing or pulling.
If it had been pulling coolant from the tank that would have indicated air in the system.
Generally temp issues at idle are form lack of air flow.
How much space do you have between the flex fan tips and the shroud?
Can you get an engine oil temp once warmed up?
Neal
If it had been pulling coolant from the tank that would have indicated air in the system.
Generally temp issues at idle are form lack of air flow.
How much space do you have between the flex fan tips and the shroud?
Can you get an engine oil temp once warmed up?
Neal
Thread Starter
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
Its been a while since I've used a flex fan but I seem to remember that it can be bolted on either way pushing or pulling.
If it had been pulling coolant from the tank that would have indicated air in the system.
Generally temp issues at idle are form lack of air flow.
How much space do you have between the flex fan tips and the shroud?
Can you get an engine oil temp once warmed up?
Neal
If it had been pulling coolant from the tank that would have indicated air in the system.
Generally temp issues at idle are form lack of air flow.
How much space do you have between the flex fan tips and the shroud?
Can you get an engine oil temp once warmed up?
Neal
I really appreciate your time and replies in this matter.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
I fought mine for a couple years before being able to drive it without cooling issues so I know how frustrating it can be.
Did you try misting water on the radiator to see if the temps would come down after it warms up?
I don't have the factory fan on mine to get some sort of idea on how much clearance there is between the factory fan and shroud to see if your in the ball park. I do know that re-circulation can be an issue if its not correct.
I think you mentioned that you had made sure that the shroud is tight against the radiator and there are no holes for air to enter and bypass the radiator.
Verify the water pump is for a standard V-belt setup and not for a serpentine setup (counter rotation). Will still move water but not near as much as the correct rotation.
I temporarily installed a section of clear tubing so I could watch the water flow between the T-stat and radiator. A good pump will move allot of water.
Verify the T-stat is installed in the right direction (point pointing to the radiator). This would not prevent cooling but would prolong the opening of the stat.
Just throwing ideas out there, things I tried when I was trouble shooting mine.
Neal
Did you try misting water on the radiator to see if the temps would come down after it warms up?
I don't have the factory fan on mine to get some sort of idea on how much clearance there is between the factory fan and shroud to see if your in the ball park. I do know that re-circulation can be an issue if its not correct.
I think you mentioned that you had made sure that the shroud is tight against the radiator and there are no holes for air to enter and bypass the radiator.
Verify the water pump is for a standard V-belt setup and not for a serpentine setup (counter rotation). Will still move water but not near as much as the correct rotation.
I temporarily installed a section of clear tubing so I could watch the water flow between the T-stat and radiator. A good pump will move allot of water.
Verify the T-stat is installed in the right direction (point pointing to the radiator). This would not prevent cooling but would prolong the opening of the stat.
Just throwing ideas out there, things I tried when I was trouble shooting mine.
Neal
Thread Starter
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
thermostat - check
water-pump - check, I can see plenty of water moving in the radiator with the cap off.
When I hose down the radiator it does drop the engine temp but not like I would expect(whatever that should be, I don't know). Heat transfer rate for water is dramatically more than air so I should expect a change whether it is the radiator or an air flow problem. I think I am convinced I need a better radiator and I'm hoping someone would say without a doubt that's it. I don't want to spend the money and time on a good guess. I think tomorrow I will re-check the temp differential in/out on the radiator. But then again it doesn't say air-flow or cooling capacity of the radiator. This radiator is the oem least expensive option from radiator.com and has been replaced under warranty once already for a crack forming at the upper hose attachment
water-pump - check, I can see plenty of water moving in the radiator with the cap off.
When I hose down the radiator it does drop the engine temp but not like I would expect(whatever that should be, I don't know). Heat transfer rate for water is dramatically more than air so I should expect a change whether it is the radiator or an air flow problem. I think I am convinced I need a better radiator and I'm hoping someone would say without a doubt that's it. I don't want to spend the money and time on a good guess. I think tomorrow I will re-check the temp differential in/out on the radiator. But then again it doesn't say air-flow or cooling capacity of the radiator. This radiator is the oem least expensive option from radiator.com and has been replaced under warranty once already for a crack forming at the upper hose attachment
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
This would indicate that the coolant temperature is too low- unless you've left some airspace in the rad. It should be filled to the brim at all times.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
I just fought this battle of over heating, it turned out to be AiR lock, was the problem
once I finally figured out how to finall fill thru the thermostat hose. (Highest point)
I had made 3-4 attempts to fix overheating as soon as I filled thru the highest point,
it went right to operating temp and stayed there.... Air Lock !
once I finally figured out how to finall fill thru the thermostat hose. (Highest point)
I had made 3-4 attempts to fix overheating as soon as I filled thru the highest point,
it went right to operating temp and stayed there.... Air Lock !
Last edited by 69Vett; Nov 13, 2011 at 06:33 PM.
Le Mans Master
Joined: Oct 2010
Posts: 6,937
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
i agree make sure there is no air in the system. i drilled a couple holes in the thermostat to keep it flowing a little. i run 160 degree t stat.
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
I just fought this battle of over heating, it turned out to be AiR lock, was the problem
once I finally figured out how to finall fill thru the thermostat hose. (Highest point)
I had made 3-4 attempts to fix overheating as soon as I filled thru the highest point,
it went right to operating temp and stayed there.... Air Lock !
once I finally figured out how to finall fill thru the thermostat hose. (Highest point)
I had made 3-4 attempts to fix overheating as soon as I filled thru the highest point,
it went right to operating temp and stayed there.... Air Lock !
this is a easy one to do and the cost is a T-stat gasket.
One thing to check is to feel the air flow from the fan, is it blowing straight back over the engine or is blowing more outward off the tips of the blade. If its off the tips of the blade and outward the fan may need to go deeper into the shroud. If I remember correctly someone posted on this and the fan needed to be in the shroud a good bit. The trailing edge of the fan even with the shroud edge. If the radiator temp DP is marginal it will likely be air flow at the radiator at idle. The air flow once at around 40 mph will negate the need for a fan.
Hold your hand in the front of the radiator and see if you can feel the air being pulled into the radiator. I can feel the air flow being pulled into my radiator.
To say that the aluminum radiator will out cool the brass one is a hard call. I think it will if your brass radiator is marginal but if their is something else wrong it wont make up for the core issue.
Neal
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
I had holes in the thermostat, and still fought the problem.
after a radiator install, several test runs temp. just kept climbing.
after new cap and new Stat w/ holes same issue,
filled thru the radiator hose.... right to operating temp.
after a radiator install, several test runs temp. just kept climbing.
after new cap and new Stat w/ holes same issue,
filled thru the radiator hose.... right to operating temp.
Thread Starter
Instructor
Joined: Apr 2011
Posts: 167
Likes: 0
From: Jacksonville Florida
I do have the radiator full to the brim. I even filled it from the top hose/water neck connection to eliminate air pockets.
I can try to move the fan further into the shroud but I don't think I can much before it will contact the shroud.
Drifting
Joined: Jun 2005
Posts: 1,523
Likes: 1
From: grand prairie texas
What antifreeze to water ratio are you useing? If you have more antifreeze than water that will also cause the temps to run hotter. I see you are in Florida you may want to try running 60% water and 40% antifreeze. Its just another thought to try