I have a 1962 corvette. It is a 327, 4 speed, 4bbl. I have had the engine, transmittion, and radiator rebuilt but it still runs hot when at idle speed. I have had the car since 1968 and has been a constant problem. Any suggestions?

 

i have NEVER had an overheating problem in my 62 (not counting the fire... ) how about the fan? are you using a clutch-type fan, or a solid hub fan? if it's a clutch type, maybe it's bad....
Bill

 

check the gauge against actual coolant temp, as a starter.

You DO have all the fan shrouding in place, right?

Doug

 

I'm sure your gonna hear from Duke.... but one of his pet peeves is making sure the distributor is correctly mapped, that the vacuum advance is correct, and more importantly functioning properly. I am not sure of the Echlin number for the can, someone will chime in and give it. Replace it, its cheap $$$$, and it is one of the main sources for overheating...... and you thought it was due only to the radiator and water pump......

 

Buy your self an IR gun and see if the car is really over heating, you may have a poor gauge or the wrong sending unit.

oWEN

 

Ok, here's my $0.02 worth......

1. Is the radiator lower fiberglass closure panel in place? This is the fiberglass panel that extends from the bottom of the radiator support to the front valance of the car. It is mounted with screws and sealed with sealant. It keeps air from coming in the grill and under the car.
2. Do you have the gaps around the front of the radiator closed with the factory-installed rubber strip panels?
3. Is your fan shroud complete all around? I found that sealing the gaps around the fan shround against the radiator helped. I used weatherstripping pieces originally intended to be used at the rear of the convertible top!
4. Initial ignition timing at 10 to 12 degrees? Vacuum advance on distributor? If so, is it an Echlin VC 1810 or GM equal?
5. Vacuum hoses for vacuum advance connected to full ported vacuum at the carb base?
6. Are you using a CLEAN (inside and out) radiator, preferably and aluminum replacement? Are your hoses new and does the lower one have a spring inside to prevent collapsing? Are your running a 180-degree thermostat? 50-50 mix of antifreeze and distilled water?
7. Is your carburetor calibrated properly so that it is not running lean?
8. If you have a fan clutch, is it operating properly? Should spin no more than 2 times when cold. Should be stiff to turn when the engine is hot and OFF. Is your fan the proper 5-blade fan, not an aftermarket fiberglass one that were so popular in the 60's? Assuming your fan is the proper one, are the blades approximately 50% in/out of the fan shroud?

I found that sealing around the radiator with sheet rubber strips and silicone sealant, using the convertible weatherstrip around the fan shroud openings and installing a 7-blade GM factory 17-inch fan with a Z-28 fan clutch I have plenty of cooling now on my 327-340HP, vacuum advance equipped 62.

Hope these tips help.

 

If it has the correct/original radiator in it, the radiator hasn't been "rebuilt"; the original radiator was aluminum, and they can't be rebuilt/re-cored/repaired. If you have a copper/brass radiator, it's a generic replacement, with about 30% less heat rejection capability than the radiator the car was born with.

 

Most of the replacement sending units make the gages read high. A resistor in series with the sending lead can correct the gage reading.

 

[QUOTE=StickShiftCorvette]

Most of the replacement sending units make the gages read high. A resistor in series with the sending lead can correct the gage reading.[/QUOTE


Hi, I agree a resistor can correct the gauge reading but it has been my experience with this fix that the reading will not be linear in function, in other words you can correct the guage to read properly over a certain narrow range but it will not be correct over the entire range. In my case I just experimented with resisters until the gauge was reading correct at 180 degree's. Just thought you might want to be aware of this.
Larry

 

[QUOTE=dazvet]

I set mine so the gage looked right at normal operating temperature. Kawasaki had a problem with one of their sportbikes and provided a resistor to set the gage in a less "stressful" zone.

 

Accuracy on our cars is most critcal from the semi hot to overheated range. (220* -250*). If youre gonna use a resistor to trim the gauge make the calibration accurate at the critcal range and not the normal range. The purpose is to know when there is trouble.

 

[Thanks for your detailed response. I have checked the fan clutch. There does not seem to be much difference between cold and hot when turning the blades. When cold the blade goes about 1/8 rotation when I spin it. Same cold. Both ways seem fairly tight. Also I do not have an aluminum radiator. Does that matter? the heating problem only occurs when in stop and go traffic. When driving 50-60 all is well.. Do you recommend the 7 blade fan rather than the stock 5 blade. ? QUOTE=Coves4me]Ok, here's my $0.02 worth......

1. Is the radiator lower fiberglass closure panel in place? This is the fiberglass panel that extends from the bottom of the radiator support to the front valance of the car. It is mounted with screws and sealed with sealant. It keeps air from coming in the grill and under the car.
2. Do you have the gaps around the front of the radiator closed with the factory-installed rubber strip panels?
3. Is your fan shroud complete all around? I found that sealing the gaps around the fan shround against the radiator helped. I used weatherstripping pieces originally intended to be used at the rear of the convertible top!
4. Initial ignition timing at 10 to 12 degrees? Vacuum advance on distributor? If so, is it an Echlin VC 1810 or GM equal?
5. Vacuum hoses for vacuum advance connected to full ported vacuum at the carb base?
6. Are you using a CLEAN (inside and out) radiator, preferably and aluminum replacement? Are your hoses new and does the lower one have a spring inside to prevent collapsing? Are your running a 180-degree thermostat? 50-50 mix of antifreeze and distilled water?
7. Is your carburetor calibrated properly so that it is not running lean?
8. If you have a fan clutch, is it operating properly? Should spin no more than 2 times when cold. Should be stiff to turn when the engine is hot and OFF. Is your fan the proper 5-blade fan, not an aftermarket fiberglass one that were so popular in the 60's? Assuming your fan is the proper one, are the blades approximately 50% in/out of the fan shroud?

I found that sealing around the radiator with sheet rubber strips and silicone sealant, using the convertible weatherstrip around the fan shroud openings and installing a 7-blade GM factory 17-inch fan with a Z-28 fan clutch I have plenty of cooling now on my 327-340HP, vacuum advance equipped 62.

Hope these tips help. [/QUOTE]

 

i have a 62 with brass radiator running a Rochester FI 1970 350 LT1 w/vac adv, a 6 blade stainless steel flexlite fan with solid hub, and a 160 thermostat. for 30 years i didn't have anything blocking the radiator sides or have the lower fiberglass panel installed. temperature NEVER got over 180 degrees.

engine overheating has always been a mystery to me, probably something to do with gremlin's....

now that i'm installing a/c, things MAY change...
Bill

 

I have a '62 with a new 350 motor... I have been battling overheating for about a year now... I have changed out almost everything... timing and vacuum are near perfect... new aluminum radiator... new sender... new high flow 180 thermostat... I just bought the lower shroud but need to install... I have gaps around radiator... ordered side and bottom seals today... will let you know how it all turns out after install... pretty sure mine is an airflow problem...

Doesn't help you but to let you know that you are not alone...

Scott