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I have an issue with overheating. I bought my Nova and it had an aluminum radiator. It had some leaks so I changed it. Before I changed it on a hot day it would run around 200 and that’s running a vintage AC system. On a cooler day around 180 it would eventually start to overheat if idled too long. Bought a new 3 core radiator from summit racing and installed it. Didn’t bleed it well enough and thought I was good, so started driving and notice temp was rising over 230 and pulled over. Coolant was low and waited to cool down and did the bleed procedure again. I then changed the thermostat(180 w/fail safe), upper hose and new sending unit. Now I again tried to burp the coolant and was going well staying at a solid 180 at idle for awhile. So I tried to test drive it and then the temp started to go up again!!! I went and even bought that fitted funnel to help burp the radiator and now at idle it’s starts to go up in temperature! Not sure what else to do. I didn’t have any of these problems with a leaky radiator. Please help, I’m not a mechanic and bought my car trying to learn it on my own as much as possible.
 

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Fusion, I haven't had many overheating issues with my Novas. But I always read the post on SNS when someone has a mechanical issue. Took me awhile to find it when I first joined, but I now use the Search Community box at the top of the page to search the issue. When searching 'overheating', I came up with this post and the responses:



An intelligent discussion of the issue, but not the only one here on SNS, and not the only problem or solution you might have. If you don't want to wait for responses, try searching the older threads on the same issue, and they might get you done earlier, and driving your car with no issues.
 

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Discussion Starter #4
I have an issue with overheating. I bought my Nova and it had an aluminum radiator. It had some leaks so I changed it. Before I changed it on a hot day it would run around 200 and that’s running a vintage AC system. On a cooler day around 180 it would eventually start to overheat if idled too long. Bought a new 3 core radiator from summit racing and installed it. Didn’t bleed it well enough and thought I was good, so started driving and notice temp was rising over 230 and pulled over. Coolant was low and waited to cool down and did the bleed procedure again. I then changed the thermostat(180 w/fail safe), upper hose and new sending unit. Now I again tried to burp the coolant and was going well staying at a solid 180 at idle for awhile. So I tried to test drive it and then the temp started to go up again!!! I went and even bought that fitted funnel to help burp the radiator and now at idle it’s starts to go up in temperature! Not sure what else to do. I didn’t have any of these problems with a leaky radiator. Please help, I’m not a mechanic and bought my car trying to learn it on my own as much as possible.
Thanks, I’ll try that.
 

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Fusion, I haven't had many overheating issues with my Novas. But I always read the post on SNS when someone has a mechanical issue. Took me awhile to find it when I first joined, but I now use the Search Community box at the top of the page to search the issue. When searching 'overheating', I came up with this post and the responses:



An intelligent discussion of the issue, but not the only one here on SNS, and not the only problem or solution you might have. If you don't want to wait for responses, try searching the older threads on the same issue, and they might get you done earlier, and driving your car with no issues.
I read some and I’ll read that one next. It’s just frustrating when it worked ok before I changed anything and now it worse than ever. Thanks for you input!
 

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It’s just frustrating when it worked ok before I changed anything and now it worse than ever.
A lot of things can cause engine overheating. The most likely culprits are usually improper ignition timing, too lean of fuel mixture, fan(s) do not move enough air thru radiator during idle and slow speeds, no (or too shallow) fan shroud, poor... or incorrect water pump flow, blockage in cooling system, and a radiator that is insufficient (too small) to handle the cooling needs.

Based on your original post and the statement shown above, my guess is the Summit radiator that you just installed may not be able to handle the cooling needs of your engine.
*What is the core size of the aluminum radiator that was in the Nova prior to replacement?...did it have 2 rows of 1" tubing?
*What is the core size of the Summit radiator you just installed (part # would help). What is the tubing size of the Summit radiator?

*What type of radiator fan are you currently using (mechanical with or without clutch... or electric)?
*Are you currently using a fan shroud? If so, can you provide some details.

You may also want to use an IR heat gun to check your actual coolant temps when the engine is hot to confirm reading shown on your temp gauge is accurate.

I strongly agree with AllyMcReal that using the "Search Community" feature within this forum could provide you with a wealth of useful information that may help you troubleshoot and fix your overheating issue.
 

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Well I had the same problem with the Car I have. I changed the radiator to a bigger aluminum one and a new 180 thermostat and that did not help. what I did do next because of this was pull off the Intake Manifold and found the Issue. the Intake manifold gasket did not have the metal plate for the exhaust ports that heat up the manifold. So I replaced the gasket with one that blocked it off and have had no Problems even in the summer It never over heats. I have an Electric fan and very seldom use it.
 

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Discussion Starter #9
A lot of things can cause engine overheating. The most likely culprits are usually improper ignition timing, too lean of fuel mixture, fan(s) do not move enough air thru radiator during idle and slow speeds, no (or too shallow) fan shroud, poor... or incorrect water pump flow, blockage in cooling system, and a radiator that is insufficient (too small) to handle the cooling needs.

Based on your original post and the statement shown above, my guess is the Summit radiator that you just installed may not be able to handle the cooling needs of your engine.
*What is the core size of the aluminum radiator that was in the Nova prior to replacement?...did it have 2 rows of 1" tubing?
*What is the core size of the Summit radiator you just installed (part # SUM-384027would help). What is the tubing size of the Summit radiator? 3 core and same fit as old old and looks exactly the same. Bolted right in.

*What type of radiator fan are you currently using (mechanical )

*Are you currently using a fan shroud

You may also want to use an IR heat gun to check your actual coolant temps when the engine is hot to confirm reading shown on your temp gauge is accurate. Used a heat gun on the outlet it goes up to 140 degrees and about 120 degrees through the radiator cap when open.

I strongly agree with AllyMcReal that using the "Search Community" feature within this forum could provide you with a wealth of useful information that may help you troubleshoot and fix your overheating issue.
A lot of things can cause engine overheating. The most likely culprits are usually improper ignition timing, too lean of fuel mixture, fan(s) do not move enough air thru radiator during idle and slow speeds, no (or too shallow) fan shroud, poor... or incorrect water pump flow, blockage in cooling system, and a radiator that is insufficient (too small) to handle the cooling needs.

Based on your original post and the statement shown above, my guess is the Summit radiator that you just installed may not be able to handle the cooling needs of your engine.
*What is the core size of the aluminum radiator that was in the Nova prior to replacement?...did it have 2 rows of 1" tubing?
*What is the core size of the Summit radiator you just installed (part # would help). What is the tubing size of the Summit radiator?

*What type of radiator fan are you currently using (mechanical with or without clutch... or electric)?
*Are you currently using a fan shroud? If so, can you provide some details.

You may also want to use an IR heat gun to check your actual coolant temps when the engine is hot to confirm reading shown on your temp gauge is accurate.

I strongly agree with AllyMcReal that using the "Search Community" feature within this forum could provide you with a wealth of useful information that may help you troubleshoot and fix your overheating issue.
Changed the thermostat a few times, 160, 180 and 195. Not after idling for over 29 minutes, still didn’t get hit enough, waited longer and now goes up to 230 degrees. I changed the thermostat, radiator, coolant sensor(which was different than the one I had), also changed the harmonic balancer and all hoses.
 

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To start with, I would look for restrictions to the flow, like a collapsing lower radiator hose. There should be a wire support in there.
Next, I would install a shroud and seal the radiator to the support to keep warm air from being recirculated around them.
 

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Use a shorter fan spacer to move the fan further away from the radiator but still clear the fan belt and engine components. Now you need a shroud. The fan you have may be too big in diameter for a shroud that fits your rad. Best is to have shroud that covers all or most of the radiator fin surface. Even more important is a close fit of the fan to the shroud. Think of the fan and shroud as a vacuum cleaner. The closer the fit the more suction you will have. Better shrouds are not the flat ones that are close to the fin surface. This should look after air flow. The engine and the tuning(afr and ignition) need to be optimum. Thermostat tip is the towing or heavy duty ones that have a larger water flow capacity when open. A few small hole on the perimeter of the thermostat helps water flow too.
 
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