I have a '62, matching number, high mileage, very original with .060 over 340 hp (old rebuild) otherwise stock with an overheating problem. During warm days and in town at lower speed the engine builts heat quickly to 220+. When purchased the block and radiator were very dirty with rust and particles. I have had radiator (original) professionally cleaned and repaired (4-5 small leaks), flushed the block several times, replaced the water pump, ran with and without thermostat and direct driven the clutch fan with no noticeable change. At highway speeds the temperature stays at approx. 180 but will rise as I slow or ambient temp is 85+. Temp will creep to 220 and past. I have checked and set ignition timing, cam timing and added octane booster. There are no obvious indications of combustion leaks. With little left to check I am coming to the conclusion that the radiator is partially plugged. I hate to change $600-$900 parts and be wrong. What have I missed?
-
-
Re: '62 Overheating
John,
There may be quite a bit, and you may need to go back and re-check that all components of the cooling system are functioning and in place as they should be.
Also, you might be interested in watching or joining in Chip Churuckian's post (just a few below and before yours) on his BB Cooling Problem. Some of the Archived postings as well as his information my contain the solution you are looking for. Tom #24014 -
Re: '62 Overheating
John,
There may be quite a bit, and you may need to go back and re-check that all components of the cooling system are functioning and in place as they should be.
Also, you might be interested in watching or joining in Chip Churuckian's post (just a few below and before yours) on his BB Cooling Problem. Some of the Archived postings as well as his information my contain the solution you are looking for. Tom #24014Comment
-
PS: John: '62 Overheating
John,
Your focus on the radiator may or may not be the problem, but you may also need to do the things you were thinking with it just to eliminate it from question.
If you have a reputable and FULL service radiator specialist available then first (before you remove the radiator yourself) take your car to him and have him check two things: 1) the radiator's function and 2) test for the presence of exhaust gases leaking into the cooling system. I know you mentioned doubt of an exhaust type leak, but have you checked it to the point of definitely eliminating it from the list? Some could be so slight that it would invade the cooling system in the "short" time period that you mentioned.
You also mentioned having 4 or 5 leaks repaired in your radiator already and I don't know the condition of all your components, but you may be due for a new one anyhow. Hope this can help. Tom #24014Comment
-
PS: John: '62 Overheating
John,
Your focus on the radiator may or may not be the problem, but you may also need to do the things you were thinking with it just to eliminate it from question.
If you have a reputable and FULL service radiator specialist available then first (before you remove the radiator yourself) take your car to him and have him check two things: 1) the radiator's function and 2) test for the presence of exhaust gases leaking into the cooling system. I know you mentioned doubt of an exhaust type leak, but have you checked it to the point of definitely eliminating it from the list? Some could be so slight that it would invade the cooling system in the "short" time period that you mentioned.
You also mentioned having 4 or 5 leaks repaired in your radiator already and I don't know the condition of all your components, but you may be due for a new one anyhow. Hope this can help. Tom #24014Comment
-
Re: '62 Overheating
Just wondered if you checked some things that arent cooling related but could cause you to overheat. Are the timing and carb settings correct? Both could cause extra heat that would show up more at slower speeds. Also are the factory seals and shroud in place? As for the thermostat removing it will make the problem worse since the coolant will go through the rad so quickly that it wont have time to cool. If its any inspiration my 58 used to be the same but once I had the rad recored and everything else put to stock it only goes above 180 in stop and go traffic. Hope this helps somewhat and good luck!Comment
-
Re: '62 Overheating
Just wondered if you checked some things that arent cooling related but could cause you to overheat. Are the timing and carb settings correct? Both could cause extra heat that would show up more at slower speeds. Also are the factory seals and shroud in place? As for the thermostat removing it will make the problem worse since the coolant will go through the rad so quickly that it wont have time to cool. If its any inspiration my 58 used to be the same but once I had the rad recored and everything else put to stock it only goes above 180 in stop and go traffic. Hope this helps somewhat and good luck!Comment
-
Re: '62 Overheating
GOOD description of symptoms/prior action(s)!!! Sure sounds to me like you've got an air flow issue. Key is when car is at speed and natural convection air flows through rad, your temp is OK. When car slows, it taxes the integrity of the radiator's fins (bent ones deflect air), the shroud/seal system, the fan (lots of these cars do NOT have original Corvette fans on 'em), and the hydraulic fan clutch.
The last item is notorious for delivering the symptoms you descibe. It's job is to increase air flow at low RPM and/or high ambient temp conditions (sound familiar). Its turn on/off points were tailored to the Corvette's heat generating profile and the silhouette of the cooling system. Fortunately, NCRS member, Fred Oliva, Vintage Automotive Research, has this problem pretty well licked with his fan clutch rebuild service. See the archieves and/or your copy of Driveline for contact specifics....Comment
-
Re: '62 Overheating
GOOD description of symptoms/prior action(s)!!! Sure sounds to me like you've got an air flow issue. Key is when car is at speed and natural convection air flows through rad, your temp is OK. When car slows, it taxes the integrity of the radiator's fins (bent ones deflect air), the shroud/seal system, the fan (lots of these cars do NOT have original Corvette fans on 'em), and the hydraulic fan clutch.
The last item is notorious for delivering the symptoms you descibe. It's job is to increase air flow at low RPM and/or high ambient temp conditions (sound familiar). Its turn on/off points were tailored to the Corvette's heat generating profile and the silhouette of the cooling system. Fortunately, NCRS member, Fred Oliva, Vintage Automotive Research, has this problem pretty well licked with his fan clutch rebuild service. See the archieves and/or your copy of Driveline for contact specifics....Comment
-
Kris: Water flow
Kris,
Can you give me more information about the fast flow of coolant through the radiator / cooling system? I've been working on the cooling system for my 68 L89 and finally have it down to an acceptable parameter (for me). But I am also investigating the possibility of engine "capability" for circulating the coolant too fast (hence not enough cooling time).
This could turn into a "sensitive issue" since I have seen / heard opposite views, but, in theory, I see little use for the need of a radiator if the object was to run coolant as fast as possible through it. The only possible explaination I can find for the "fast-as-possible (opinion?)" is that any or all engines are NOT capable of circulating coolant fast enough to make any difference. Others welcome to join in also. Tom #24014Comment
-
Kris: Water flow
Kris,
Can you give me more information about the fast flow of coolant through the radiator / cooling system? I've been working on the cooling system for my 68 L89 and finally have it down to an acceptable parameter (for me). But I am also investigating the possibility of engine "capability" for circulating the coolant too fast (hence not enough cooling time).
This could turn into a "sensitive issue" since I have seen / heard opposite views, but, in theory, I see little use for the need of a radiator if the object was to run coolant as fast as possible through it. The only possible explaination I can find for the "fast-as-possible (opinion?)" is that any or all engines are NOT capable of circulating coolant fast enough to make any difference. Others welcome to join in also. Tom #24014Comment
-
Re: '62 Overheating
Hi John - One thing I missed in your description - In addition to all the other things you have correctly checked, have you run resistance checks on your temp sending element? There are several great articles in the Restorer about this (search article index in this forum). After market replacement elements are noteworthy for having improper resistances, and generally indicating higher than actual. Again, Fred Oliva is also the man to check sensors. Just one more oddities our 62 (straight axle) world. Cheers, DickComment
-
Re: '62 Overheating
Hi John - One thing I missed in your description - In addition to all the other things you have correctly checked, have you run resistance checks on your temp sending element? There are several great articles in the Restorer about this (search article index in this forum). After market replacement elements are noteworthy for having improper resistances, and generally indicating higher than actual. Again, Fred Oliva is also the man to check sensors. Just one more oddities our 62 (straight axle) world. Cheers, DickComment
-
Re: '62 Overheating
I am having the same type of overheating problems. I have a new alum. radiator,had the fan clutch rebuilt,no help, put a new fan clutch on, same thing.Removed the temp. sender and used a mechanical gauge. Rebuilt motor,new water pump,timing chain, all seals around the radiator. Runs 170 degs. down the road, but with in five minutes of idle time it will get to 220 degs. Engine bore is 30 over. Many different rad. caps and thermostats.Dave #2739Comment
-
Re: '62 Overheating
I am having the same type of overheating problems. I have a new alum. radiator,had the fan clutch rebuilt,no help, put a new fan clutch on, same thing.Removed the temp. sender and used a mechanical gauge. Rebuilt motor,new water pump,timing chain, all seals around the radiator. Runs 170 degs. down the road, but with in five minutes of idle time it will get to 220 degs. Engine bore is 30 over. Many different rad. caps and thermostats.Dave #2739Comment
Comment