You don't really want the car running cooler than 180. Less than that changes the way the fuel responds in the cylinder, and can cut mileage and raise emissions. You can also lose some throttle response, depending on your set up. Many new FWD cars operate in the 200 to 230 range as normal.

A flex fan can be a help sometimes. Depending on size and amount of flex, and how the car is driven. Flex fans flatten out their blades as RPM and air drag increase. This stops extra horsepower drag at speed.
If you are at high RPM with low road speed, the flex fan may not deliver enough air. This is unlikely for most of us. So a flex fan can be a option. Just make sure the one you choose moves enough air to cool the car.

|UPDATED|5/7/2004 9:57:18 AM (AZT)|/UPDATED|

I just wanted to let you guys know that I ran a flex fan in my 80 with the shroud, and it overheated every time, then I got a flex fan that was practically touching the shroud on every side because I thought air might be getting by, still overheated. I tried spacers that would move the fan deeper into the shroud, still overheated. I wouldn't recommend it. I went with a regular duty fan clutch and a regular fan after that and it ran hot, then I went with a heavy duty fan clutch and stock fan. 190 degrees, that is where I am currently. I would skip the flexers alltogether.

Anyone out there using an elctric fan..

The flexalite Dual fan fitted for corvette
http://www.flex-a-lite.com/auto/html/27inch-electric.html

or the spal dual 11
http://www.spal-usa.com/pdfs/11Fans.pdf

ive seen articles on both of these installed in vettes successfully..

anyone here done this..

personally the only thing I want running off my engine is a high output alternator... I think it would be doable if they make an electric PS pump...

I concur with the posts mentioning anything to do with directing the air-flow. My '76 would run over 200 in the summer - with or without the AC on.

As you can see in the pic below, I added a lower pace car spoiler. Now the car runs right around 190 consistently.

Not saying that's the cure, but it definitely helps!

I tried driving only in the shade for awhile, but the road didn't cooperate...

FWIW, my flexie keeps things in the 180 - 190 range, on a mildly modified small block. Lunched the fan clutch about a year ago - it locked up and the fan tried to go horizontal helicopter, pulling the water pump free of the seals. In the middle of the Mass. Turnpike. Not neat.

About that bouncing from 180 to 220 and back again. If it's really a bounce, gotta wonder if you have trapped air in the system, i.e. its gotta get burped. Just read about that in the current issue of Hemmings Muscle Machines --- the same pub that dissed "double-rubber-bumper" Vettes in the Auction Action section. Yes, I wrote Lentinello a polite note, suggesting he muzzle the author.

"My ride, my way!"

Well, I've checked all the obvious places. Fan, fan clutch, shroud (thanks Kyster), new radiator cap, hoses are new. It seems that if I stay around 1500-2000 rpm the temp stays in the normal range. When I get on the accelerator within a few minutes the temp rises to 220. I guess I'll spend some more time this week going flushing out the system and changing the thermostat. Until then it's off to watch my son play LaCrosse and then well, tomorrow would not be a good day to convince my wife I should work on the car.

Sounds like some kind of restriction from the description. I would have said maybe the lower radiator hose, but you said the hoses are new. BTW - does the new lower hose have a spring in it? If not, it could be collapsing at higher rpms, new or not. A lot of new radiator hoses now are not coming with the anti-collapse springs.

Definitely get it flushed thoroughly. You could still have a restriction in the radiator or even the timing could be advanced too far.

Good luck...this is the time of year to be out driving and enjoying our cars, not fixing them.

After you flush do a back flush too. When completed let the car run with the radiator cap off to purge air out of the system.. If it still overheats I would remove the radiator and have it tested at a reliable radiator shop.. Removal is fairly easy..

Roy

Red Line puts out a great product called "Water Wetter". It works by reducing the surface tension of the coolant to the radiator fins. I got a 30 degree drop, down to around 180. Best of all, its only $7-$8 for a bottle and you just add it to the radiator. My $0.02 for what it's worth.

Justice Brothers also make a wetter called Radiator Cool. It works very well. I have used it in problem systems. What it, and others like it, does is increase the ability of the water to transfer heat due to reduction of the water surface tension. When it can absorb and release more heat, the car runs cooler. This will also help a heater put out more heat. While most of our C3s don't go out when it that cold, this could help your daily driver.

Another thing to look at is the antifreeze. The reason it is called antifreeze coolant is it also helps raise the boiling point of the coolant. The corrosion protection in antifreeze is also important. It keeps rust from building in your cooling system.
Up to 50% gives you the maximum boil protection. Of course the radiator cap helps as well. For every 1 pound of pressure, the boiling point is raised 3 Degrees F. Water boils at 212 F. at sea level, and about 210 where I am due to less air pressure. With a 15 pound cap that raises the boiling point to 255 F. Antifreeze raises it more. Contamination drops it. Most of our pressure caps no longer hold a full 15 psi. We don't want them that hot anyway.

The problem is if you mix over a 60% antifreeze mixture, you start to inhibit heat transfer. Any car can run hot or overheat due to too much antifreeze concentration, with nothing else wrong.