Fan clutch question

[90idahoblazer]

I just drove home tonight from work...approx 10 miles.......Just for kicks I wanted to see what you folks were talking about when the engine is hot the fan should be stiff to turn....well mine spun like a pixie wheel in the wind.....what temp does the clutch tighten up......will it make that much of a difference at high speeds or only at low speeds....does the clutch engauge or help with 60 MPH airflow across the radiator.....I know this is basic maintenance...ask me about an aircraft engine and I can help you....thanks in advance

 

[prjt_blzr]

The cluthc fan should be fully engaged when the engine is hot (about 220*). Most engines do not need the airflow at 60mph as there is sufficient airflow to cool the rad. My clutch works rather well on my K30 and quite often I can spin the thing freely when it is "hot". If your vehicle is not running hot I wouldn't worry about it as it is working.

 

[90idahoblazer]

thanks

 

['73 K5]

Look on the front of the clutch itself. If it has a spring thing on the front then that means its a thermostatic one and should be hard to turn if your engine is hot. Get a new one if it spins easy.
BUT if your clutch is sealed in the front with just plain metal, then that kind is an RPM activated fan and you can't really test those at rest...they're cheaper so I usually avoid them. Whether they are good or bad, they always spin freely at rest since they're RPM controlled.

'73 K5
Chevy good...Ford bad

 

[Smitty]

Keep in mind that the thermostatic type won't react to temp changes as fast as the guage in your dash. It will work off the temp of the air coming through the radiator. I put one of the heavy duty ones designed for low geared vehicles on mine and when I was breaking my new camshaft in (running my engine at around 2000 rpm for around an hour) you could really tell when that fan kicked in. It sure had a way of getting my attention in a hurry, especially when I was watching to make sure everything was staying together.

Smitty

 

[90idahoblazer]

Good Advice guys thanks....I will look ad see what I have...I believe its the sealed version