(COOLING)How does the Fan Clutch Work? - RX7Club.com - Mazda RX7 Forum

(COOLING)How does the Fan Clutch Work?


Old 08-24-07, 11:07 AM
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(COOLING)How does the Fan Clutch Work?

I have been troubleshooting a cooling issue on my 1982 GS for the past few weeks and I have replaced just about everything. Upper/lower rad hoses, OEM thermastat, thermastat gasket, water pump gasket, and boiled the radiator.

The day I put everything back together and ran it, the temp was perfect (It sat at about 3/8th on the Temp Gauge). That was after city and about an hour of highway driving. However, the next day the temp gauge was back to where it was before I replaced everything (5/8th on the gauge) after a less than an hour of city and highway driving. When I turned on the heater, the temp gauge went back to 3/8ths. Both days, I drove it around the same time and the outside temp was about 78ish.

I searched the best I could on the forums and looking in my Haynes manual. I found a few ways to troubleshoot the radiator fan. When the engine is cold, the fan spins freely and stops after about 3-4 times around. When the engine is at operating temp, the fan still spins 3-4 times around. Are there any other ways to troubleshoot it?

My questions are: Is my fan clutch/drive damaged/broke? And for my information, how does the fan drive/clutch work?

Note* I read another thread that mentions the need to have the lower engine compartment cover on to help the cooling system. I will placing that back on tonight.
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Old 08-24-07, 11:19 AM
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Here it tells you what to do to determine if the clutch is bad http://www.landsharkoz.com/tt/ttvfc.htm
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Old 08-24-07, 12:18 PM
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Your clutch on the fan sounds like its toast. Also that bottom cover helps to force the air through the radiator, without it your temps will rise. At 78 degrees ambient that guage should be less than 1/3. Get the fan working and the shroud back on and see whats next. You may need to replace the oil cooler lines as well. I found that magically cured my own temperature problem.

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Old 08-24-07, 12:34 PM
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Thanks for the info Bruceman.

T_G, I was hoping those lines were okay because it ran well the first day and the second day it was fine after I turned on the heater. I am saving for new oil lines, since I spent my monthly car project budget trying to fix this cooling issue.
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Old 08-24-07, 12:43 PM
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You said at operating temp, the fan will spin 3-4 times? That's a little too loose at temp. As the temp gets warmer, there should be more resistance in the clutch. However, not having that lower pan in place will compound the problem.
In stop and go traffic, the fan does all work. Once out on the highway, there should be enough airflow to keep it cool. Without the lower pan, the air can go under, rather than thru, the radiator.
Putting that back in place should help, but you may still need to replace the fan clutch.
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Old 08-24-07, 02:50 PM
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Old 08-24-07, 05:01 PM
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Your fan clutch is bad, end of story.
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Old 08-24-07, 05:19 PM
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Thanks everyone for your help/advise.

doc, +1 for archiving?
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