Author Topic: Keeping cool  (Read 5417 times)

bc69

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Keeping cool
« on: June 28, 2010, 03:49:15 AM »
Have 69 sb 350 w/air. Like to Cruise and have been having trouble with heat building to point around 240-50 deg way to warm, and will not recover very fast. When it does, it's lucky to get back under 200. I have 3 core stock in car now..... Any suggestions?.... Thinking of 4 core or maybe 3 core aluminum. I'm somewhat a fanatic in keeping stock. But I do not want overheating when it can be addressed.
Brad
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fireZ

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Re: Keeping cool
« Reply #1 on: June 28, 2010, 11:49:35 AM »
I use a 160 degree thermostat and also use a couple small bottles of Royal Purple Rad cool . My car is a 68 Z28 with a stock 302. I am able to drive in 90 degree weather all day long. Try this and see. I use to run a 185 thermostat but it was too hot and when the stat finally opened and it was to late for the rad and cooling system to bring temps back down. Just a thought
1968 Z28 LA Built
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fireZ

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Re: Keeping cool
« Reply #2 on: June 28, 2010, 12:40:29 PM »
The additive is called Royal Purple Ice
1968 Z28 LA Built
LIC # RPO Z28

JohnZ

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Re: Keeping cool
« Reply #3 on: June 28, 2010, 03:02:43 PM »
Have 69 sb 350 w/air. Like to Cruise and have been having trouble with heat building to point around 240-50 deg way to warm, and will not recover very fast. When it does, it's lucky to get back under 200. I have 3 core stock in car now..... Any suggestions?.... Thinking of 4 core or maybe 3 core aluminum. I'm somewhat a fanatic in keeping stock. But I do not want overheating when it can be addressed.

How old is the radiator? Have you verified the accuracy of the temp gauge with an I.R. gun "shot" of the upper radiator hose just above the thermostat housing? Do you have the stock shroud, fan, and clutch in place? They didn't overheat with a 3-core radiator when new, and shouldn't now if the stock cooling system is in good shape (especially the radiator).

Cooling margin can be improved by sealing the radiator to the support and the shroud to the radiator with foam pipe seal (Lowe's, Home Depot, etc.) to force all of the incoming air through the radiator core (instead of around it); also make sure the original rubber flap seal is in place between the top of the radiator support and the hood inner panel, to stop recirculation of hot air over the support and through the radiator.
'69 Z/28
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qwertyme77

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Re: Keeping cool
« Reply #4 on: June 30, 2010, 07:10:43 AM »
don't forget about your fan clutch. At least i assume you have one as my 68 a/c car did. Mine was worn out and would cause my car to overheat even without the a/c on in hot weather. After I replaced it, the overheat went away. The fan clutch is not very noticeable and rarely mentioned as a cause for overheating.

JohnZ

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Re: Keeping cool
« Reply #5 on: June 30, 2010, 03:29:33 PM »
The various "cures-in-a-bottle" (Purple Ice, Water-Wetter, etc.) are all designed to be used if you use only water as a coolant (as most race sanctioning bodies require where anti-freeze is prohibited due to the difficulty of track cleanup); they're primarily surfactants, which minimize formation of steam pockets at "hot spots" in coolant passages. All commercial anti-freeze formulations already contain surfactants in their additive packages, which gradually get weaker over time as the additives do their job, which is why OEM's and anti-freeze manufacturers recommend changing coolant every 2-3 years. If you change your coolant on that schedule, the "cures in a bottle" will have no effect whatsoever on cooling performance - they're just a placebo. The cures for cooling problems come in boxes, not bottles.

The article at the link below was written for Corvettes and published in "Corvette Enthusiast" magazine, but it applies to the components of ANY cooling system; it explains how the cooling system works, and debunks much of the "internet misinformation" you hear about cooling problems:

http://www.lbfun.com/warehouse/tech_info/cooling%20system/cooling.pdf
'69 Z/28
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bc69

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Re: Keeping cool
« Reply #6 on: July 19, 2010, 01:34:19 AM »
Thanks for the info. Addressing the seals around the shrouds and such now. The rad was slightly plugged. And...... Figured that I would see if I could find out how to place the hood - radiator support seal..............what a helpful and informative web sight!
Brad
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