Topic: Re: Flex Fan or no Flex Fan
in Forum: C3 Cooling and Heating Systems
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You guys talk about Flex Fans letting go. The previous owner of my '73 BB had the stock clutch fan fly apart. It took out part of the shroud and blew a large hole in the hood! It took him 3 days on the road to get parts and get it fixed. I never liked the sound of the fan on this engine. At higher RPM's all I can hear is the fan. It makes me want to shift to get rid of the crappy noise. I'm going with DeWitts dual electric fans and hopefully, they'll only come on in traffic.
John
1973 BB 4-Speed Coupe Project Car
2009 Z06 Mostly Stock
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Frederick, MD - USA
Joined: 9/8/2003
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Vette(s): 1969 convertible L71 427/435 4-speed black interior
If your fan is as loud as you say then someone may have replaced the original fan clutch with an incorrect one. That's not uncommon when they're replaced.
I will say that if you're not concerned about originality electric fans are the way to go.
Flush out that radiator while you got it apart....I mean alot!!! I flush mine 2 times every year....it looks like stalactites in there!! Or I hate to say remove it and have it cleaned.....but...flush kits are cheap and clean out the goop really good...LMK!!!!
My first parade at Carlisle 2010
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
Rick, I had the same symptoms and was finally cured by a bottom hose with the spring. What was happening was the bottom hose without the spring would collapse while driving. The spring cured it - everything else on the car was new so no other gremlins.
Hope the bottom hose solves the mystery for you.
Paul
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John...the problem with my car is that the radiator is original and had little to no maintenance in its life..I may remove it this winter and get it cleaned out...hope Rick doesn't have to do that and the new hose with the spring works out.
My first parade at Carlisle 2010
Got my new hose today from corvette America. If all go right I'll be putting it on Thursday afternoon( got a interview in the morning) ....so I will post after I try it out will let you all know if successful.
Rick
|UPDATED|11/27/2012 5:56:50 PM (AZT)|/UPDATED|
|UPDATED|11/27/2012 5:56:50 PM (AZT)|/UPDATED|
Hope the new lower does the trick. Running abit without the t-stat in place would also let you see it the radiator is indeed cooling enough. If there is a build up of rust and/or scale in the radiator that could impede the cooling. A fellow on the Model A club I've joined has recommended running pure vinegar in the cooling system to dissolve the crub. He claims it cleaned everything out clean as a whistle. I know the cooling systems between a Model A and a C3 Corvette are quite abit different but they're very similar in function.
Also make sure the radiator support seals are in place. Any air slipping through the gaps between the radiator support and the radiator is air that isn't helping to cool.
Jim Olson 
"The Toys"...!!! Save the Wave! 
Just two comments.
Don't forget to check the actual flow. I have seen water pumps that seem okay but have impleller blades rotted or rusted to the point they either are not there or have come loose from the shaft. It just won't pump the coolant. Uncommon, but not rare.
Removing the thermostat completely will allow a quick check, but when driven can acutally CAUSE and overheat problem. The stat acts like a restrictor to flow, slowing it down at high engine speed. IF the coolant flows too fast it can travel through the radiator quicker than it can be cooled, resulting in still too hot coolant going back into the engine, and not cooling, but overheating instead.
While this usually does not happen at low to medium engine RPM, many driving conditions can cause this to happen. Often racers will remove the t-stat but install a restrictor in it's place. This is nothing but a large washer with a hole in it to control the coolant flow.
Of course removing the t-stat and starting the car will allow you to see the volicity of the coolant flow through the radiator, if you can see in the tank. Some of our designs may prevent getting a clear view, but most will allow it.
Good flex fans work fine & will tolerate 10K RPM. I've used them on various cars for many yrs with no problems. If your car is overheating & you have a correctly placed fan, clutch,flex or electric you have other issues. Making sure all air goes through the radiator is a real problem & will cause overheating at highway speeds on C-3's. If your bottom hose is being sucked in your radiator is probably clogged. Water wetter will really help bring the temp down 10-20 degrees & running a 25% antifreeze mixture will help too. water dissipates heat much better than antifreeze, but you need some antifreeze to control corrosion. I personally use flex fans on 2 high performance engines & they keep the engine right at 175-180 degrees in all weather. I also have one with electric fans that also work fine. Flex fan can be noisy , but if you exhaust is noisy you'll never notice it. So I think it really comes down to a personal choice. Flex fans can be adjusted in & out to really get the proper air flow which is critical to coolling efficiency.
Alan
in Forum: C3 Cooling and Heating Systems
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