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Discussion Starter · #1 ·
Hi guys.

Back with questions.

My bird has a flex fan on it, and when its sits at idle it heats up fast. Driving it runs right at 180.

I have a guy who has a clutch fan he will sell me for 35 bucks. My engine is from a 72 GTO, he said he thinks it will fit.

I currently have no shrouds, this car was a stock 6cyl but the radiator was replaced in 2003. Do you know if all engine model firebirds in 67 used the same shrouds?

I think running a 160 thermostat, clutch fan and shrouds should help stay cool.

Thanks!
Stan
 

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IMO u need a fan shroud not a clutch fan, maybe a new radiator, when's last time you flushed engine and heater

Mine would boil over if idle to long, new rad, flush everything and new 50-50 coolant, fixed
 

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Another option is to get an electric cooling fan that mounts right up flush with the radiator. You can mount it on either side of the radiator, just make sure it spins so the wind from it goes through the radiator the same

direction the wind coming through the grill when your going down the road - that is, towards the engine. Not sure what shrouds are going for these days, but with an electric fan, you get a few ponies freed up, don't have to mess with fan spacers, and an electric fan can be spinning fast while your car is just sitting at idle. Whereas a belt fan can only spin the same speed as the engine, that is, slow fan speed at idle, when you really need the fan the most, is not the best set up to keep your engine cool.
 

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According to what I see in the pic, the rad is a narrow one--maybe a 2-row ? I'd buy a cheap alum 2-row, with at least 1 inch wide tubes. These are said to cool as good or slightly better than the factory 4-row rads. The cheapest one I've seen listed is the American Eagle brand, made by Champion.

http://www.ebay.com/itm/1967-1969-Chevy-Camaro-Sm-Block-Aluminum-2-Row-1-Tubes-American-Eagle-Radiator-/272172320720?hash=item3f5ebc07d0:g:H~gAAOSwvgdW6JPm&vxp=mtr

http://www.ebay.com/itm/American-Eagle-AE337-Pontiac-Firebird-2-Row-1-Tubes-/121892759559?hash=item1c615fe807:g:Rh4AAOSwG-1WvexH&vxp=mtr

http://www.jegs.com/i/Champion-Cooling-Systems/166/AE337/10002/-1

It appears that your fan is at least 5 inches away from the rad. Therefore it can not be pulling much air thru the rad. It would help slightly to use a fan spacer, to move the fan closer to the rad. But, as mentioned, a good shroud would be better. I've read that if you use a shroud, you should position the fan so that it is aprox half in and half out of the shroud. Any farther up inside the shroud results in less air flow. I don't understand it, but I've read that, in a LOT of online cooling info.

http://www.jegs.com/i/OER/691/9788883/10002/-1?parentProductId=

Many use a clutch fan in order to free up some power, after the vehicle gets up to speed. Some don't like the extra noise of a HD flex fan. But Hayden makes a 7-blade flex fan which is said to pull lots of air. Or, you can go with a factory 7-blade clutch fan , and a Severe Duty Hayden clutch.

http://www.amazon.com/Hayden-Inc-3718-Flex-Fan/dp/B000C3F3H0

http://www.amazon.com/gp/offer-listing/B000C3F3D4/ref=dp_olp_new?ie=UTF8&condition=new

http://www.ebay.com/itm/New-OAW-12-G2797-Thermal-Fan-Clutch-for-GM-Chevy-Buick-Ford-Pontiac-/150968234681?hash=item23266872b9:g:l1UAAOxyQyJRm~7B&vxp=mtr

Some have good results with the electric fans. But, they come with their own set of problems. I've read that, for a performance Pontiac engine, you need a fan or fans that will pull near 5000cfm of air. MOST electric fans won't pull that much air. :no Some truck fans will. One popular junkyard option is a fan from a Mark VIII Lincoln. These are said, by some, to pull 5000cfm when functioning at max performance. There are usually some for sale on Ebay.

http://www.ebay.com/sch/Lincoln-Mark-VIII-Fans-Kits/33600/bn_1429207/i.html

BUT, a fan or fans that will pull that much air also take a lot of amps to operate. So, they require heavy duty wire, relays, etc--must have an adequate electrical harness and set-up to run HD fans safely and efficiently.

Also, if you haven't already done it, the divider plate to water pump impeller fin clearance should be reduced to a minimum. Some have been found to have nearly 1/4" gap, which will not allow the pump to move the coolant efficiently.

http://www.wallaceracing.com/water-pump-mods.php

http://www.firebirdnation.com/forums/topic/17258-water-pump-mod/

 

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We had all kinds of overheating problems. A 160* thermostat is too low. We're running a 180* or 190* (can't remember which one!), I think 180* is stock. Have you pressure tested the cooling system? We had a very small leak that was letting air into the system. Also make sure you have the right radiator cap.
 

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I think even just a shroud would really help out. Your basically circulating hot air around the engine compartment instead of "pulling" air thru the radiator. I like my electric fans with aluminum radiator. Was a cheap conversion for me. <$200 bux.
 

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Discussion Starter · #8 ·
Thanks guys!

Im ot sure how many rows the radiator has, i hope 3. This carbis still at my dads, i live abot 20 miles from him and its still not safe to drive that far. I will count the rows tomorrow.

The radiator, pump and fluids have less than 500 miles on them, but they were all replaced in 2003. I plan to flush the system when i get it home.

My dad says it always ran hot at idle with this set up, i can see why.

With all your input i think i settled on: new clutch, new fan, new 180 thermostat and new shrouds. He has no documentaion on the radiator he put in, but if it still doesnt cool i will be springing for that aluminum one.
 

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Looks like a 6-cyl radiator with no shroud...no way it's gonna cool that 400.
A 4-row (I have no experience with the 2-row aluminum radiators mentioned) and a shroud should take care of it.
 

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Many pontiac over heating are timing issues.Retarded timing will cause them to run hot.I alway start there.I have been building and driving pontiac for more than 50 years.I have 4 in my garage right now,4 bolt water pump.8 bolt water pump and 11 bolt water pump.All factory pumps.Have never check clearance.I alway try to use the factory flex fans with a shroud.I use 160 thermos.My 421 SD tempest has a alu radiator just because with my engine placement I could not run a factory one.None over heat at idle or on the highway.Just lucky I guess.My 69 bird has a 366 NASCAR RA V engine with a factory 350 auto radiator with a factory shroud with no issue either.Tom
 

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Take off cap look in rad, if you see white crusty stuff, rads part of the problem, I suggest buy a shroud and mount bracket, go from there, check timing , dwell etc. That's free
 

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...

Many use a clutch fan in order to free up some power, after the vehicle gets up to speed. Some don't like the extra noise of a HD flex fan. But Hayden makes a 7-blade flex fan which is said to pull lots of air. Or, you can go with a factory 7-blade clutch fan , and a Severe Duty Hayden clutch.

http://www.amazon.com/gp/offer-listing/B000C3F3D4/ref=dp_olp_new?ie=UTF8&condition=new

http://www.ebay.com/itm/New-OAW-12-G2797-Thermal-Fan-Clutch-for-GM-Chevy-Buick-Ford-Pontiac-/150968234681?hash=item23266872b9:g:l1UAAOxyQyJRm~7B&vxp=mtr

....

Also, if you haven't already done it, the divider plate to water pump impeller fin clearance should be reduced to a minimum. Some have been found to have nearly 1/4" gap, which will not allow the pump to move the coolant efficiently.

http://www.wallaceracing.com/water-pump-mods.php

http://www.firebirdnation.com/forums/topic/17258-water-pump-mod/
ponyakr, this is very informative, an excellent summary! And while this subject is there, I would like to ask couple more questions. I have that Flexfan (see pic) and yes the noise bothers me totally it sounds like truck really so I will upgrade to clutch fan. Could you add a link to compatible fan? Because clearly I cant mount the same Flexfan on the clutch. And generally I would like to go through the cooling on my 400 Firebird anyway, it all needs to be reviewed and cleaned up at least. I will pull the pump and check the clearance too. Any other parts besides the gasket need to be replaced if I pull the pump?

Yeah and thermostat, so the stock is 180F? Which one you recommend? I dont know how it affects engine and performance - going with cooler thermostat or hotter. I just know that aluminum engines run hotter like for BMW the cooland tems go up to 230F. Would be interesting why manufacturers stick with different temps, there must be a reason.

Thanks,

Neal

firebird_fan.png
 

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I am running the stock x blade fan that runs constant, measure the shroud opening and how deep from pump to shroud and hit the bone yard, I would think a second Gen should fit
 

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"...I will upgrade to clutch fan. Could you add a link to compatible fan?..."

There are usually some factory 7-blade Pontiac clutch fans on Ebay.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2051541.m570.l1313.TR0.TRC0.H0.X7-blade+Pontiac+clutch+fan.TRS0&_nkw=7-blade+Pontiac+clutch+fan&_sacat=6000

Can also find some with an ad on the PY site.

http://forums.maxperformanceinc.com/forums/forumdisplay.php?f=446

"...Any other parts besides the gasket need to be replaced if I pull the pump?..."

Need to make sure the divider plates and transfer tubes are in good shape. They, and even the timing cover itself, can corrode and deteriorate, reducing efficiency. Can even get so bad it'll allow coolant to drain into the oil pan. :(

"...measure the shroud opening and how deep from pump to shroud and hit the bone yard, I would think a second Gen should fit..."

I suppose one might possibly be modified to work. But in stock form, the 1st and 2nd gen shrouds are nothing alike. :no

http://www.ebay.com/itm/1970-1981-TRANS-AM-FIREBIRD-RADIATOR-FAN-SHROUD-PONTIAC-ENGINE-/182065988363?hash=item2a63fa830b:g:HVQAAOSwQjNW9Fie&vxp=mtr

http://www.ebay.com/itm/NOS-GM-1967-69-Pontiac-Firebird-Trans-Am-Camaro-RADIATOR-FAN-SHROUD-9788883-/252209491235?hash=item3ab8db6d23:g:BTsAAOSwbdpWU8A~&vxp=mtr
 

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1968 Convertible 400, 200 4R, 1971 Formula 400 M-22 Rock Crusher, 1984 Trans Am...........
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If it helps you, mine overheated with a flex fan and shroud. I had to switch to clutch fan.
 

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Discussion Starter · #17 ·
Im in the process of removing the flex fan and installing the clutch fan. Im hoping my 3 row radiator is good enough, if not ill pursue a good 4 row.
 

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I just thought of something else we did that seemed to help. We put a fill valve in the heater hose between the heater core and the engine. While not necessary, it did make it much easier to make sure the core, the block, and radiator were all full of coolant before we started troubleshooting.
 
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