66 corvette over heating
#1
66 corvette over heating
I got a 66 corvette big block engine bored 60 over, have a direct fit Bcool radiator, have 3000 CFM electric fan, high volume aluminum water pump, new heater core, all new hoses, using manual pulling fan also, has changed thermostat 3 times and currently using 160 degree thermostat and have tried 180 and 190, while driving it runs 220 degrees at idle when stopped it pegs out. Have tried water additives both fans are pullers. Has heads resurfaced. Can someone please tell me why its still heating?
#2
Team Owner
Have you used a IR gun to verify your temps?
#3
Team Owner
Member Since: Oct 2000
Location: Washington Michigan
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I got a 66 corvette big block engine bored 60 over, have a direct fit Bcool radiator, have 3000 CFM electric fan, high volume aluminum water pump, new heater core, all new hoses, using manual pulling fan also, has changed thermostat 3 times and currently using 160 degree thermostat and have tried 180 and 190, while driving it runs 220 degrees at idle when stopped it pegs out. Have tried water additives both fans are pullers. Has heads resurfaced. Can someone please tell me why its still heating?
You might also read this article to help you better understand your Corvette cooling system, how it works, and how to diagnose it:
http://www.lbfun.com/warehouse/tech_...em/cooling.pdf
#4
Le Mans Master
Member Since: Nov 2000
Location: Going too fast over the hill. Iowa
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The usual suspects:
Temp gauge accuracy
Ported vacuum advance
Incorrect timing
Engine fan on backwards
Fan clutch defective
Radiator not big enough (in BTUs)
No shroud
Shroud not sealed
The usual helpful mods:
Large core aluminum radiator
Heavy duty water pump
Closed cooling system with overflow tank
High volume electric puller fans
Shroud with high speed vent doors
Extra seal to prevent air recirculation under the shroud.
Install AC rad support seal
Remove engine splash shields
Temp gauge accuracy
Ported vacuum advance
Incorrect timing
Engine fan on backwards
Fan clutch defective
Radiator not big enough (in BTUs)
No shroud
Shroud not sealed
The usual helpful mods:
Large core aluminum radiator
Heavy duty water pump
Closed cooling system with overflow tank
High volume electric puller fans
Shroud with high speed vent doors
Extra seal to prevent air recirculation under the shroud.
Install AC rad support seal
Remove engine splash shields
Last edited by magicv8; 07-07-2013 at 04:40 PM.
#5
Race Director
Member Since: Jan 2002
Location: Close to DC
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C2 of the Year Finalist - Modified 2020
Last, but not the least...how fresh is the rebuild on the engine? How many miles relative to being broken in. Fresh/tight engines can and will run hot. Dennis
#7
Step #1 is to determine if you really have a problem; have you compared the ACTUAL coolant temperature with an I.R. gun "shot" of the upper radiator hose just above the thermostat housing against what the temp gauge reads at the same time so you know what the gauge is really telling you? Corvette temp gauges are notoriously inaccurate to the high side.
You might also read this article to help you better understand your Corvette cooling system, how it works, and how to diagnose it:
http://www.lbfun.com/warehouse/tech_...em/cooling.pdf
You might also read this article to help you better understand your Corvette cooling system, how it works, and how to diagnose it:
http://www.lbfun.com/warehouse/tech_...em/cooling.pdf
#8
The usual suspects:
Temp gauge accuracy
Ported vacuum advance
Incorrect timing
Engine fan on backwards
Fan clutch defective
Radiator not big enough (in BTUs)
No shroud
Shroud not sealed
The usual helpful mods:
Large core aluminum radiator
Heavy duty water pump
Closed cooling system with overflow tank
High volume electric puller fans
Shroud with high speed vent doors
Extra seal to prevent air recirculation under the shroud.
Install AC rad support seal
Remove engine splash shields
Temp gauge accuracy
Ported vacuum advance
Incorrect timing
Engine fan on backwards
Fan clutch defective
Radiator not big enough (in BTUs)
No shroud
Shroud not sealed
The usual helpful mods:
Large core aluminum radiator
Heavy duty water pump
Closed cooling system with overflow tank
High volume electric puller fans
Shroud with high speed vent doors
Extra seal to prevent air recirculation under the shroud.
Install AC rad support seal
Remove engine splash shields
#9
Team Owner
Member Since: Oct 2000
Location: Washington Michigan
Posts: 38,899
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1,099 Posts
several things here that I will try. Its beginning to drive me crazy. Been at this over a month. Have large core radiator, be cool brand, electric fan, closed cooling system with over flow tank, have 2900 cfm electric fan, heavy duty water pump, haven't removed splash shied and don't have high speed vent doors.
What about your base timing, centrifugal advance map, vacuum advance, and what your vacuum advance is connected to? Read the article again - those things matter.
Last edited by JohnZ; 07-07-2013 at 08:02 PM.
#10
Instructor
If you replaced the stock radiator with an aftermarket radiator and you're NOT using the stock overfill tank, it is possible that the cylinder heads are not filling up completely with coolant. Check by disconnecting the upper radiator hose at the radiator and filling the engine with coolant at the filler cap until coolant is flowing out of the hose.
#12
Concur on checking for the correct head gasket. What heads are on it? Original or aluminum. Aluminum radiator? What antifreeze are you using? How much time on the motor since heads were last off? I've seen a few cases of galvanic corrosion build up caused by aluminum heads or water pumps used with the wrong antifreeze or tap water. This can cause blockage of cooling passages, typically in the heads. Make sure you dilute your antifreeze with distilled water.
#13
Burning Brakes
If you replaced the stock radiator with an aftermarket radiator and you're NOT using the stock overfill tank, it is possible that the cylinder heads are not filling up completely with coolant. Check by disconnecting the upper radiator hose at the radiator and filling the engine with coolant at the filler cap until coolant is flowing out of the hose.
Origonally a 66 BB did not have a side mounted expansion tank or an aluminum rad .
Bill