Hey guys! I was thinking about switching to electric fans. Do you guys think I should run dual fans or do you think I would be just as well off with a single fan. I have a 4 core radiator cooling a 350. It does run pretty warm during the summertime but i'm also running a/c though to. It's pretty much only when i'm running on the interstate. I have a 190 degree thermostat but I don't think that would have much of an effect on it then. It's getting up to about 225-230 degrees at 75 mph but at 55 mph it's at 190 then. Do you think the coolant is just running too quickly through system? If so, what do you think I should do to slow it down? Thanks for the help guys.

Sounds like a good setup would be, a dual fan,set your sensor for around the same as the thermostat and should be a good way to go

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Ricks 64 SS Convertible (http://www.geocities.com/pinball4570_win/classic_white.html)

What thermostat are you running? Do you have a shroud on it now? Auto or stick? If auto any additional coolers & what stall on converter? What else has been done to the engine?

Hey thank's for the info! I am running a 190 degree thermostat and I have no additional coolers. I am running a fan shroud on it and it's th-350 with a stock stall. Is all i'v really done is the normal stuff like boring it 30 over and a mild 440/480 engle cam. Nothing really to major and i'm only running 3400 rpm's at 70 mph. I have a pretty high gear ratio. They are 2.72's. Thanks again for the help!!!

Adding a trans cooler would help too. Double ck hoses and thermostat that all is well befor spending $ on stuff. Good luck.

Anything you can do to get cooler air through the rad will help. External trans coolers work great, I eliminate the internal rad cooler completely on my own car. I'd get the biggest one I could.
Thermostats only maintain MIN temp. If it's hitting 225-230 with a 190 t-stat in it, it would probably do the same with a 180 or less in it. As stated above, dual fans would work well. I think they look cool too. I would set the sensors to come on at 200 or so.

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Don
1969 Chevelle 2dr. project in progress.
Can't wait to drive it!

Check the hoses as well. A lot of times at speed the hoses will begin to collapse restricting flow. Doesn't happen at low speeds so it's difficult to spot. If it has started recently and nothing else has been changed, it's a place to start.

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TC Gold #92/ACES #1709
67 SS & 67 Elky
GR8PMKN (http://www.dalesplace.com/images/chevelle/more_pics/p001182.jpg)

Dale's Place (http://www.dalesplace.com) Team 67 (http://www.team67.com)
Midwest Chevelle Regional Governing Council (http://www.midwestchevelles.com)
Integrity: If you have it, it doesn't matter - If you don't have it, it doesn't matter.

First I would check all the less expensive usual things like the Thermostat, hoses, etc, If everything checks out OK you may want to just go to your local reputable radiator shop and ask them about a "dimple core" to put on your existing tanks. These will cool MUCH more than what you have. Many prefer these to the aluminum types. I've been very happy with the one I've put on my car.

--Jim

I don't understand the high rpms, with the 270s, thats about what I run with the 3.73s. I'm using 4 core with shroud and 4 blade running the ac. 396 4speed 180 ripping, 200 traffic. I'm for checking hoses and belts first.

I'm running a 350 a/c radiator in my car now,,,3 row with a shroud and stock clutch fan...it does not even overheat...something aint right with your car.

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Bob West 1972 Malibu
454+.030/3900 lbs.
TH350-3.73's
1.66 60 ft. 7.47-91.68 11.78 @ 114.59
1/8th 1.66 7.46@91.70

72,
(Are you guys ashamed of your real names ?? )
If your tach is correct, and you really are running at 3400 rpm with 2.72 gears...I think that is where your problem is. With those gears and a normal size tire, I would guess you should be in the 2200 rpm range. Given the information you have posted...it sounds like your transmission is slipping badly, causing the excess heat. My 71 had a fairly stout 350 with 3.73 gears and the stock single core radiator and 4 blade fan and made the 500 mile trip back and forth from Md to Mass many a time back in the mid 70's without ever breaking a sweat. Back then the speed limit was 75 the entire way.
I say figure out why the rpms are so high and you will solve the problem. http://www.fordmuscle.com/calculator/rpm.shtml

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100

Mod. must be sleeping today, should be in the Heating and cooling forum http://www.chevelles.com/forum/smile.gif

Mike

The only other reason he could be turning that many RPMs is having a stall speed converter that might stall that many RPMs. All that slipping can cause an engine to get hot as well as the tranny. I always drill a couple of 1/8" holes in the thermostat now just in case it does not open all the way or gets stuck shut.

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69 Malibu 406 3680lbs Turbo 350 2400 stall, 3.73,XE274, Performer RPM Q-JET, 800 Q-JET, Sportsman2 64cc 11TO1 12.65@105.5 mph

ACES Member #3635
Tri-State Chevelle Member# TSC-010
Larry G.

Another one of my shot in the dark solutions: Do you have an air dam? Also all gaps between the radiator and radiator support, top, bottom and sides should be sealed to insure all the air goes thru the radiator not around it. Personally I think you have more serious problems, but one never knows. As mentioned before start cheap, you might be suprised.

Whoops, forgot something! At speeds over 45-55 (depending on the car) there should be more airflow through the radiator than any fan can provide. So what I'm saying is that overheating at freeway speed should not be a fan issue.

BillK has a good point about RPMs. My 69 Camaro with 15" wheels 70 series tires runs around 3100 at 70mph....and I have a 3.55. Either your rear end is NOT what you think, the tach is wrong or you have major issues with the tranny.

None the less, I don't think a hot tranny will drive your temps up to the range you mention by itself. The efficiency of the radiator increases exponentially as speed goes up. One poster got it right....this is NOT a fan issue whereas you should be outstripping your fans ability to produce productive airflow at around 25mph. So, I think this is either a collapsing lower hose, so make sure you have a spring and no kinks, or an overly lean condition which can easily out demand the best radiators. Check and read the plugs. My guess is that it's lean too.

Go to Jack'Stands Cooling Tips (http://www.inccn.net/techforum.htm) for more cooling tips.

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Steve "Jack'stands" Jack
Tech forum at www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)



[This message has been edited by HOTRODSRJ (edited 12-09-2002).]

Lol, you guys might find this funny i have a 180 degree stat and, manual 2 core radiator with a 454 backed behind it stock fan long water pump and shroud gets 190 all day hehehe

Tom, that doesn't surprise me at all. The 454 is one of the easiest blocks to cool with very large coolant passages. Flow is king, remember. I have a friend with a 500hp+ 454 and his car is a piece of cake with an aluminum radiator/high flow pump etc. Some of the small blocks can be a real pistol to get flow thru and thus you have to be on your toes to do it correctly. They are not all created equal. And..let's not even start to talk about the 502 marine block. Small coolant passages, all cylinders siamesed together, large quenching masses....just a nightmare if you don't get it right on.

Things that affect the ability of your cooling system to cool are;

Radiator finnal area and media type

water pump capacity

airflow thru the radiator

water content of the coolant

pressure capability of the system

block type (have differing coolant jackets)

head type (aluminum heads have smaller coolant galleries)

intake outlet designs

horsepower (more hp....more gasoline....more waste heat.....more heat to be carried away...even at idle)

tuning (too lean conditions at idle or cruising)

front opening of car

airconditioning and/or tranny cooling integration

total system volume/capacity

hose design and size

So, as you can see there are alot of anomolies at work here.

Just some fun stuff to think about.



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Steve "Jack'stands" Jack
Tech forum at www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)

Hey guys! Sorry I couldn't get back to you guys befor now to rectify this problem with the rpm's thing. I'v been out in the field the past few day's so i havn't been anywhere around a computer to check this but my car actually runs at 2800 rpm's at 75 mph. I was thinking about something totaly different. I'm sorry about that guys. I'v looked at the entire system and i'v replaced all the hoses because it was getting ready to be needing it. Other then that I havn't really had a whole lot of time to mess with just yet though but I will keep you guys informed if I do find something. Sorry about that again and I really appreciate all the help you guys have given me.