[67GTONUT]

Well..... looks ok to me....

I would look at that waterpump.....

[geeteeohguy]

The fan is too far into the shroud. Should be half in, half out. Too far into the shroud can cause turbulence issues and effect cooling. Also, it seems that the newer clutch fans are designed for newer cars with operating temps that are about 220. The fans seem to be calibrated to come on above 220 degrees. There are threads here about the do's and don't's of thermal spring tweaking. Be advised that running at 220 at idle on a hot day is not a real-world problem, since the temp drops when you start moving again. Because the temp is normal when driving and heats up at stand-still, you are not pulling enough air thru the radiator core. Since your focus is on a 190 constant operating temp, I'd re-mount the fan and calibrate the clutch to engage sooner. As an aside, are you running the bra on the front of the car? That could restrict airflow and cause your problem, as well.

[fiesta62]

Originally Posted by george kujanski

Welding a plateto the impeller is ok, but if the clearance from the face of the impeller to the inside surfaceof the pump housing is too large, the coolant recirculates around the impeller rather than get sucked in from the radiator to the cooling passages, and hence there is not enuf coolant flow thru the radiator.

Check that gap and insure it is at a minimum.

George

ok i will ask my mechanic about this and see if did it correct but i think he would have....thanks

[fiesta62]

Originally Posted by geeteeohguy

The fan is too far into the shroud. Should be half in, half out. Too far into the shroud can cause turbulence issues and effect cooling. Also, it seems that the newer clutch fans are designed for newer cars with operating temps that are about 220. The fans seem to be calibrated to come on above 220 degrees. There are threads here about the do's and don't's of thermal spring tweaking. Be advised that running at 220 at idle on a hot day is not a real-world problem, since the temp drops when you start moving again. Because the temp is normal when driving and heats up at stand-still, you are not pulling enough air thru the radiator core. Since your focus is on a 190 constant operating temp, I'd re-mount the fan and calibrate the clutch to engage sooner. As an aside, are you running the bra on the front of the car? That could restrict airflow and cause your problem, as well.

i have read many times fan should be half way to 2 /3rds in the shroud , its right on 2/3rds in but i will run it by my mechanic today as he is going to look at adjusting the spring on the clutch...he thinks the hayden is set to come on at 190 but we are checking on this...also the hayden severe duty clutch i bought is listed for a 67 gto so i assume they have designed it correct, but we will look at this spring adjusting idea...
i got the bra but only use it on long freeway drives never around town.

[fiesta62]

ok geetee i had another look at fan distance into shroud , fan as u suggested was quite far into shroud, my mechanic noticed the spacer a said remove it, so spacer is gone and now fan has moved out of shroud a bit over half inch so now blades are not as far into shroud as u can see in pics....so we will see if it makes any difference

also we adjusted the spring on the clutch to open sooner, i will test drive tomorrow my mechanic used a heat gun and thermometre to adjust but said its trial and error....i'm betting he got it right first time, fingers crossed

if this dont work i am considering a larger fan 19.5 inch and larger shroud....

[scorpio ps]

My story. 70 Judge I purchased ten years ago. From day one the car ran hot. How hot? Very hot. I'm certain that if i kept driving it would peg the temp gauge. As a result I didn't want to drive it. I have three other cars that run cool so I always have something to drive. Fast forward one month ago I decided to do something about the overheating problem on the Judge. First thing I did was to confirm the temp by purchasing a good quality under dash temp gauge. I live in Hawaii so I took out the thermostat. My stock radiator was in good shape. All I did was flush it out. Timing was fine. Blocked the wheels, placed it in "D" turned on the A/C wide open and let the car idle for 45 minutes. Guess what. Under dash gauge reads 185-190 while the in dash gauge was pegged. Then I took it for a drive and got caught in heavy traffic, standing still cause of construction up ahead for a long time. My sphincter was working overtime needless to say. Never went above 195. I'm not saying that is the same problem you are having. I'm just saying that not all is black and white. Listen to Charles, he's on the right track. Go slow and methodical. Confirm and move on to the next step. You can always spend $$$$$ but try to get the most bang for your buck. Alooooha......

[68 Firebird]

when I first got my Firebird it only had an idiot light in the dash. i drove it as a play car for a year and thrashed it hard and never thought about the temps. Then I installed a nice
auto meter gauge setup and found myself staring at the oil pressure and temps.

Good Luck

Gerry

[geeteeohguy]

Yes, the spacing looks much better now, Tony. Years ago, I had a '66 GTO that ran hot all the time, too. 230-245 in traffic. Never seemed to overheat, but the factory gauge would get waaaay up there. I sold the car, and before I let it go I cleaned up some of the hacked wiring under the dash.....and re-installed the disconnected ground wire to the dash cluster. Whammo....the "temperature" went from 230+ to 190. The car never WAS running hot all that time.

[scorpio ps]

Originally Posted by geeteeohguy

Yes, the spacing looks much better now, Tony. Years ago, I had a '66 GTO that ran hot all the time, too. 230-245 in traffic. Never seemed to overheat, but the factory gauge would get waaaay up there. I sold the car, and before I let it go I cleaned up some of the hacked wiring under the dash.....and re-installed the disconnected ground wire to the dash cluster. Whammo....the "temperature" went from 230+ to 190. The car never WAS running hot all that time.

Thats what I had. Wiring... Would any other gauges in the dash be affected or does the fuel gauge have its own ground.

[fiesta62]

its not a gauge issue, i have stock gauge and aftermarket both read similar, car runs 190 driving which is as expected, temp goes up only while sitting for 5 minutes or more...we have narrowed it down to fan not pulling enough air in thru grill....we put a towel in front of my grill and in front of my friends 66 gto, my towel hardly moved his towel got sucked in tight over the grill, he has a 19.5 inch fan off a chrysler that he modified, i have a stock 17.5 inch fan....the obvious answer is i need a bigger 19.5 inch fan and larger shroud , i know shroud will need to be modified, problem is i called ames and py they dont sell 19.5 inch fans only 17.5, can anyone advise where can i find a 19.5 fan ? thanks

[scorpio ps]

"we put a towel in front of my grill and in front of my friends 66 gto, my towel hardly moved his towel". ......

Thats funny. I see why you need more inches. Was his towel dry or wet. Lol

[FrankieT/A]

I was looking at your pics. What I noticed was the paint on your radiator looks to be real thick. How does it look in the core area? Thick paint hinders heat transfer. As far as aluminum radiators go, aluminum dissipates heat way better than brass. Big time! Warm a piece of brass and a piece of aluminum where it's a little too hot to touch see which cools faster. This is retorical of course, aluminum radiators cool far better than brass recored or not.

[fiesta62]

Originally Posted by FrankieT/A

I was looking at your pics. What I noticed was the paint on your radiator looks to be real thick. How does it look in the core area? Thick paint hinders heat transfer. As far as aluminum radiators go, aluminum dissipates heat way better than brass. Big time! Warm a piece of brass and a piece of aluminum where it's a little too hot to touch see which cools faster. This is retorical of course, aluminum radiators cool far better than brass recored or not.

core replaced with a max flow it has not got thick paint over it....problem we feel is fan not pulling enough air....i need a larger fan but where can i find a 19.5 inch fan...

[scorpio ps]

Can you do something with this.

http://www.ebay.com/sch/sis.html?_kw...r+Part+No+1319

[67GTONUT]

I dont know..... not buying the bigger fan idea.

The reason for the bigger fans was to help pull air thru the a/c condensor and the radiator.... Your car should not be running hot because of a 17" fan....

I would still replace that waterpump with a cast impeller with the proper clearance to the divider plate, and start there.....

[fiesta62]

Originally Posted by 67GTONUT

I dont know..... not buying the bigger fan idea.

The reason for the bigger fans was to help pull air thru the a/c condensor and the radiator.... Your car should not be running hot because of a 17" fan....

I would still replace that waterpump with a cast impeller with the proper clearance to the divider plate, and start there.....

well car is cool when moving as its got air coming in, when still no air, the towel test proves how week my fan pulls compared to my friends larger fan on his 66....seems like if i pulled more air with bigger fan as i would when moving then problem should be solved....

[FrankieT/A]

The rest of us have 17" fans. If changing to a 19" was the fix all trust me(us) we'd all be doing it. I for one live in south Florida have A/C and use it. I've battled hot Pontiacs for years. On this build (455 10:1+ and a ram air IV cam) I have no cooling problems what so ever. Here's my recipe, take it for what it's worth. My water pump has been clearenced, it uses the crappy sheet metal impeller, Champion cheapie aluminum radiator, 160* thermostat, severe duty fan clutch out of a big block duallie truck, a 15lb. rad cap and all stock pieces intact, fan shroud, fan, etc. Never runs hot even idling with A/C on. On the highway it runs at about 180* with 43* at the vents. And if I had to say what the biggest factor is, its "the radiator". All my other cars have four core radiators in great condition and none of them run as cool as this one, and they all have the same tricks.

Keep in mind that not only does brass not shed heat like aluminum but the thicker the radiator, like 4 core, the less air flow. More tubes equals more restriction. Not a big deal over 40 MPH, but at a stand still your fan has to deal with that. Ever notice a lot of aftermarket aluminum radiators (and factory ones for that matter) are usually 1 row maybe 2? Granted the tube is an inch thick. Just my opinion, I hope this gives you some more ideas.

[geeteeohguy]

Tony, I'm with you on the fan not pulling enough air at idle. Fans vary in blade pitch as well as diameter. A bigger diameter does pull more air. I was able to get a good used fan off of a 1970 Pontiac (19.5") on ebay a couple of years back for $20. I would suggest the py classifieds or ebay. A fan should pull enough air to hold a dollar bill or a towel tight against the core at idle. You're on the right track, IMO.

[68 Firebird]

there are many 7 blade A/C stylr fans on ebay, thats where I got mine to try.

Mine is from a 1970 GTO with ac and 400/TH400. When I put it on to test even
crusty I saw a difference, even with old std duty clutch. Went to the HD hayden
just to be safe. I only have a 3 row stock style copper radiator and feel a larger unit
would be even better yet. Either 4 row or aluminum when a replacement is needed.

Gerry

[fiesta62]

i have spoke with my mechanic friend and he has actually made a test bench to test fans , he can measure how much air a fan pulls, he has the 19.5 factory 7 blade fan, and others including the ram air fan, he said the 19.5 factory 7 blade was one of the poorest performing fan in his test, mostly because of the low pitch blades, its not just the fan size its pitch too, he had a whole bunch of fans to show me and test results, one of the better ones was the 19.3 inch flexalite flex fan, i am considering removing the clutch and trying this fan or similar, my shroud opening is 20 inch so should fit ok.....anyone tried the flex fans ?