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overheating 427/400

 
Old 09-14-2011, 02:30 PM
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ZEEEE06
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Default overheating 427/400

When I first got it about 2 months ago, it would overheat on the highway and at idle. Now it overheats after 5+ minutes of idle. runs cool on the highway.

Things I've done:
Checked thermostat 160*...works fine
Confirmed guage is correct with IR gun.
Removed electric pusher fan
Flushed radiator and block
Fresh antifreeze/distilled water
Ran vacuum can hose from manifold vacuum
Installed Pertronix ignition
set timing at 8* initial, vacuum advance is working properly.
Water pump appears to be pumping fine
6 year old copper radiator with only 1800 miles, appears fine.
Compression is 170 or more in all cylinders
installed clutch fan eliminator

I drive for 1/2 hour or more (with Vintage a/c on) and it's running around 170-180. When I stop and let it idle, the guage slowly creeps up to the point where it's about to overheat.

Any ideas on what else I can do or check?

Last edited by ZEEEE06; 09-14-2011 at 02:32 PM.
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Old 09-14-2011, 02:35 PM
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JohnZ
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Define "overheats" - what does the temp gauge read, does it puke coolant from the overflow hose, does the temp come back down when you drive it? What radiator and fan do you have? Need more info on what happens when.
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Old 09-14-2011, 02:40 PM
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Originally Posted by JohnZ View Post
Define "overheats" - what does the temp gauge read, does it puke coolant from the overflow hose, does the temp come back down when you drive it? What radiator and fan do you have? Need more info on what happens when.
also if i may...is this a fresh re build or do you know??....if so did you re build it or the previous owner
these bb cars do not overheat if everything is up to snuff.....
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Old 09-14-2011, 02:56 PM
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Originally Posted by JohnZ View Post
Define "overheats" - what does the temp gauge read, does it puke coolant from the overflow hose, does the temp come back down when you drive it? What radiator and fan do you have? Need more info on what happens when.
Temp guage is headed for the red zone when I shut it down. IR at the thermo housing reads 240. It does puke. Temp does come back down when I drive it just after the overheat condition. copper Harrison radiator and stock 5 blade fan.
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Old 09-14-2011, 02:57 PM
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Originally Posted by midyearvette View Post
also if i may...is this a fresh re build or do you know??....if so did you re build it or the previous owner
these bb cars do not overheat if everything is up to snuff.....
Rebuilt by previous owner 6 years and 1800 miles ago.
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Old 09-14-2011, 03:04 PM
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Originally Posted by ZEEEE06 View Post
Rebuilt by previous owner 6 years and 1800 miles ago.
the approach to this issue is to first test the block and heads for an internal combustion leak providing you have faith in the cooling components installed already
napa sells a "block check" system detector that works with a fluid that turns colors to rule out the block and heads for an internal leak
with only 1800 miles on the build, one could suspect it did this with the previous owner and may have not been disclosed at the time of sale
anyway, that's where i would start the diagnosis....jmo.....good luck...

it could be something simple like head bolt torque or improper sealer used for the head bolts, etc.
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Old 09-14-2011, 03:10 PM
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i just noticed you installed a clutch fan eliminator.....some fans are not designed for use over 4000 rpm's....fyi
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Old 09-14-2011, 03:20 PM
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Originally Posted by midyearvette View Post
i just noticed you installed a clutch fan eliminator.....some fans are not designed for use over 4000 rpm's....fyi

I don't like the eliminators, on my driver big blocks I ran a 74-75 fan (7 blade and more pitch) with one of the same year HD fan clutch's, you could hear the fan kick on at temp...sounded like a prop plane. I also like to ad the AC lower shroud extension, and the ac upper rubber flap and seals to help. as for running hot at idle, it is lack of airflow through the radiator. kept my car cool even in a parade.
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Old 09-14-2011, 04:07 PM
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I installed the eliminator to rule out a bad fan clutch. The fan clutch will bo back on.
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Old 02-10-2019, 09:48 PM
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do you have a fan shroud

are the fins on the outside of rad clean

are all the foam pieces around the rad and support
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Old 02-11-2019, 01:35 AM
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It's a 7 year old thread😊
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