High Temp Resolved!!
Safety Car
Joined: Mar 2009
Posts: 4,191
Likes: 951
From: Corpus Christi, TX
Jeff:
You may be right about the opening size in the reproduction fan blade; it is for a 71-73 AC big block. Unfortunately, no one else seems to have any reproduction 7 blade fans. Until a few years ago, Paragon Reproductions made a 64-67 AC fan, but no more.
You'd have to use a 71-73 model fan clutch. God only knows if the water pump flange bolt pattern is the same as on mid years.
You may be right about the opening size in the reproduction fan blade; it is for a 71-73 AC big block. Unfortunately, no one else seems to have any reproduction 7 blade fans. Until a few years ago, Paragon Reproductions made a 64-67 AC fan, but no more.
You'd have to use a 71-73 model fan clutch. God only knows if the water pump flange bolt pattern is the same as on mid years.
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
Burning Brakes
Joined: Jun 2007
Posts: 945
Likes: 8
From: Miami FL
Haven’t had much free time lately but I did finally spent some time on my overheating problem. Turns out I had two issues. The car was running much hotter than expected after I installed VA. Turns out my clutch fan was going bad (less than 2 years old). That explains why playing with the clutch adjustment didn’t do squat. I decided to step up to a 7 blade fan and found one locally (’72 GM big block which required I also upsized the fan clutch). Car ran about 10* cooler… which is good. The rest of my problem was my refurbished temp gauge was no longer compatible with my sending unit. So the gauge reads about 17* warmer than what’s really happening. Based on IR test, I’m running about 185 to 190… I’m happy. I’ll try to roll the dice with a new sender to see if I can get a more accurate reading but at least I know my temp is in the ballpark.
As always, thanks for all the info and support!!
Joe
As always, thanks for all the info and support!!
Joe
Thread Starter
Burning Brakes
Joined: Dec 2006
Posts: 768
Likes: 1
From: Round Rock Texas
Thread Starter
Burning Brakes
Joined: Dec 2006
Posts: 768
Likes: 1
From: Round Rock Texas
The only harmonics I heard was the sound of my exhaust while I was cruising down the highway with a cool engine!! The new fan worked great!! sorry, no wooow wooow's here!
Team Owner
Joined: Aug 2007
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Army
That article is the one I posted a while back: http://forums.corvetteforum.com/c1-a...utch-fans.html.
Likewise I run a 6-blade fan and I don't notice any howling, etc.. Also replaced the fan clutch with a 1" spacer and, again, no noticeable increase in noise. Of course, with a solid lifter engine the whirring of the valve train sorta overrides all other noises...
Frank
Likewise I run a 6-blade fan and I don't notice any howling, etc.. Also replaced the fan clutch with a 1" spacer and, again, no noticeable increase in noise. Of course, with a solid lifter engine the whirring of the valve train sorta overrides all other noises...
Frank
Cruising
Joined: Aug 2009
Posts: 12
Likes: 0
From: Wakeman Ohio
I have a 1960 with a 1967 327ci stock 1960 radiator, and a stock 1960 4 blade fan. I feel she runs hot. A lot of under hood heat also. IR reading on the upper hose is 210ish. Do you think a fan swap would help?
Also what pound radiator cap should I be running?
Also what pound radiator cap should I be running?
Last edited by After U; Aug 21, 2009 at 06:49 AM.
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Team Owner
Joined: Aug 2007
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Army
First you have to define 'running hot' ... if the temp creeps up after idling then I would suggest first and foremost that you insulate all the gaps around the radiatior shroud. There are massive 1"-2" gaps that I closed in with foam pipe insulation. I would investigate the fan clutch next... I had two fail so I just replaced it with a spacer from Jeg's. Important to make sure the fan blades remain 1/2 in and 1/2 out of the radiator shroud for proper cooling after this change. Then, if there is still a problem you could certainly go for a more efficient fan replacement. I run a 13lb radiator cap with my aluminum radiator.
Cruising
Joined: Aug 2009
Posts: 12
Likes: 0
From: Wakeman Ohio
First you have to define 'running hot' ... if the temp creeps up after idling then I would suggest first and foremost that you insulate all the gaps around the radiatior shroud. There are massive 1"-2" gaps that I closed in with foam pipe insulation. I would investigate the fan clutch next... I had two fail so I just replaced it with a spacer from Jeg's. Important to make sure the fan blades remain 1/2 in and 1/2 out of the radiator shroud for proper cooling after this change. Then, if there is still a problem you could certainly go for a more efficient fan replacement. I run a 13lb radiator cap with my aluminum radiator.
By "hot" I mean that after a 15-20 mile country road drive, upper hose temp reads about 210 with my IR gun. Manifold temps are 220-230.
Burning Brakes
Joined: Jun 2007
Posts: 945
Likes: 8
From: Miami FL
There’s a lot of overheating threads (even just recently) that will give you a lot of information. Having just gone through a similar problem, I would suggest starting with the JohnZ article referenced earlier in this tread…a lot of excellent info and it covers all the basics. The temps you quoted are high. Unless you’ve made some recent change and these are your ‘normal’ temps, I would consider your rad…. might be time to give DeWitts a call.
Team Owner
Joined: Jul 2008
Posts: 23,419
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From: In limbo
St. Jude Donor '13-'15, '17 thru '22
I have a 7 blade fan with the "fingers", and it does make an audible "whoosh" when I get on it on hot days. Cruising down the road isn't so bad, but I can hear it.
I had no idea that you could adjust a fan clutch! Good info there.
As far as thermostats, I took mine out and shoved it up the passenger's side tailpipe. Now my engine runs so cool that I stick a six-pack under the hood before I go out cruising so I can have a cold beer when I get back. That's my experience, so take from it what you will.
I had no idea that you could adjust a fan clutch! Good info there.
As far as thermostats, I took mine out and shoved it up the passenger's side tailpipe. Now my engine runs so cool that I stick a six-pack under the hood before I go out cruising so I can have a cold beer when I get back. That's my experience, so take from it what you will.
