Fan clutch stays engaged pretty much all the time

JEFFREY BAU

MEMBER
1995 CHEVROLET 3500
7.4L
V8
2WD
AUTOMATIC
62,000 MILES

1995 Winnebago motor-home with a 454. As soon as it warms up the fan clutch will keep the fan engaged 95% of the time. I have replaced the fan clutch and the thermostat 195 degrees. When I drove it last year it worked like a dream. Not anymore. Any help? The radiator is really hard to get out so I'm hoping for another solution. There are no leaks of any kind. The problem is slightly worse with the A/C on but it really doesn't affect it much. Thank you

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Hi,

More than likely your fan clutch has failed.

I attached a document that helps explain how this works. Basically, there is a spring that as it heats up the silicone oil causes the fan to spin faster.

Unfortunately, it looks like there is an issue with the clutch because this is one of the more common failures with these fans.

Here is a guide that will help explain this. Let me know if you have questions.

https://www.2carpros.com/articles/fan-clutch-symptoms

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Sunday, August 25th, 2019 AT 12:18 PM

JEFFREY BAU

MEMBER
2 POSTS

I read in the Chevrolet P30 Chassis manual that this fan clutch s design to engage anytime the engine is above 150 degrees. Then progresses to more engagement as the temperature rises from there. Just so used to my pickup and every other vehicle in the world not having the fan running so much. I have added Purple Ice which is supposed to drop coolant temperature by up to 25 degrees. We'll see. I leave for California in the morning.

Thanks for your help!

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Monday, August 26th, 2019 AT 10:38 PM

KASEKENNY

MECHANIC
18,907 POSTS

Okay. I guess I should have clarified if this was a change in operation. Yes this fan is run off of a metal spring that once the temp reaches that point, it engages the fan. Then as this spring gets hotter the fan goes faster.

If this is how it is operating then it is normal. However, if the fan is making a loud roaring noise all the time, then most likely it has failed and needs replacement.

Let me know if you have any other questions. If not, have fun on your trip and come back if you have other questions. Thanks

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Tuesday, August 27th, 2019 AT 5:35 PM