Fan Clutch
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Fan Clutch
Should there be a noticeable difference in drag, ability to spin the fan by hand, between when the engine is hot and cold? I noted some resistance when the car had been sitting over night though no noticeable change in resistance after running for a few hours.
I don't want to replace the clutch unnecessarily.
I just replaced the radiator with a DeWitts, made some improvement but could be better.
This is for a 70 LS5.
I don't want to replace the clutch unnecessarily.
I just replaced the radiator with a DeWitts, made some improvement but could be better.
This is for a 70 LS5.
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Should there be a noticeable difference in drag, ability to spin the fan by hand, between when the engine is hot and cold? I noted some resistance when the car had been sitting over night though no noticeable change in resistance after running for a few hours.
I don't want to replace the clutch unnecessarily.
I just replaced the radiator with a DeWitts, made some improvement but could be better.
This is for a 70 LS5.
I don't want to replace the clutch unnecessarily.
I just replaced the radiator with a DeWitts, made some improvement but could be better.
This is for a 70 LS5.
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
I haven't tried letting it idle for a long period.
It appears to be running hotter than the thermostat (180), tends to run around 200ish. I wouldn't say it's overheating, just seems to run hotter than expected.
The temps improved after installing the DeWitts radiator but did not drop dramatically as some have seen. I can drive on the highway now without seeing the temps slowly creeping up.
I'm slowly repairing items, replaced all seals around the radiator and shroud. I need to install a new air dam/spoiler, missing... Also need to install the seal between the radiator support and hood.
It appears to be running hotter than the thermostat (180), tends to run around 200ish. I wouldn't say it's overheating, just seems to run hotter than expected.
The temps improved after installing the DeWitts radiator but did not drop dramatically as some have seen. I can drive on the highway now without seeing the temps slowly creeping up.
I'm slowly repairing items, replaced all seals around the radiator and shroud. I need to install a new air dam/spoiler, missing... Also need to install the seal between the radiator support and hood.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
After driving the car, and getting the engine up to operating temperature, watch as the engine is turned off, and see how much the fan turns after the engine is turned off. If the fan stops quickly, maybe 2 or 3 rotations or less, then I would say the clutch is fine. If the fan rotates more than 5 or so rotations, then I might consider a new clutch.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
If it's 200ish all the time including highway, there's other issues. If it's just while stopped or in traffic, that's normal.
Le Mans Master
Joined: Aug 2006
Posts: 7,423
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
If you want to test the clutch start a cold engine and let it run for two minutes and shut the car off and check the resistance to turn the fan.
Restart the car and let it run for ten minutes (up to normal operating temperture), shut it off and you should have more resistance to turn the fan.
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Melting Slicks
Joined: Jan 2003
Posts: 2,713
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From: Shreveport LA
LA Events Coordinator
BUT, during the other seasons it runs in the 180*-190*
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
As new your car had a copper, but large radiator....A 180 stat should be correct....But don't remove one thinking it will run cooler...that wont happen....
Maybe flush the engine as the next procedure
Maybe flush the engine as the next procedure
