fan
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Elder User
Joined: Oct 2004
Posts: 585
Likes: 1
From: Ct.
fan
I have read in some of the post here about the fan coming on, I am missing something, isn't the fan fixed to the water pump and there for is on all the time.
Or i just don't know how it works. all who wish to enlighted me. thanks
Or i just don't know how it works. all who wish to enlighted me. thanks
Post Fiend
Joined: Jul 2005
Posts: 14,582
Likes: 12
From: 21791
the fan has a clutch between the actual fan and the input shaft to the pump. usually it doesnt run. that is under normal operating temperatures. you cant hear it. as the air passes through the radiators, it hits the blades on the fan, and spins it at the relative speed of the air in the engine compartment.
but, when the engine senses an unusually high temperature, it kicks on the fan. this happens when you are experiencing a high load, (IE pulling a trailer WOT up a steep grade or after a long WOT drag race.) the fan can be heard screeching (it is the clutch kicking in, bringing the fan speed up to engine speed. it is a VERY audible and loud howl, you can almost tell it is it, because nothing else on the truck makes a sound of a cowled 3' wide fan spinning 3200 rpm. it is quite scary the first time you hear it. but now you know it is normal. the fan will also run a little bit when you first start it up, it will run for some odd reason until about 1400 rpm. i have heard it come on coming in my driveway after a brief encounter at 3300 rpm on a steep hill with a 15,000 pound trailer. if you hear it, you know the engine is working properly.
but, when the engine senses an unusually high temperature, it kicks on the fan. this happens when you are experiencing a high load, (IE pulling a trailer WOT up a steep grade or after a long WOT drag race.) the fan can be heard screeching (it is the clutch kicking in, bringing the fan speed up to engine speed. it is a VERY audible and loud howl, you can almost tell it is it, because nothing else on the truck makes a sound of a cowled 3' wide fan spinning 3200 rpm. it is quite scary the first time you hear it. but now you know it is normal. the fan will also run a little bit when you first start it up, it will run for some odd reason until about 1400 rpm. i have heard it come on coming in my driveway after a brief encounter at 3300 rpm on a steep hill with a 15,000 pound trailer. if you hear it, you know the engine is working properly.
Senior User
Joined: Aug 2004
Posts: 135
Likes: 0
From: California
Originally Posted by strokin_it7.3
but, when the engine senses an unusually high temperature, it kicks on the fan. this happens when you are experiencing a high load, (IE pulling a trailer WOT up a steep grade or after a long WOT drag race.) the fan can be heard screeching (it is the clutch kicking in, bringing the fan speed up to engine speed. it is a VERY audible and loud howl, you can almost tell it is it, because nothing else on the truck makes a sound of a cowled 3' wide fan spinning 3200 rpm. it is quite scary the first time you hear it.
Also, should the clutch really be screeching? Mine does (only rescently) and it drives me crazy. No $40,000.00 vehicle should screech like that in my opinion.
And yes the first time the fan kicked on I should have had a lump of coal where the sun don't shine. I would have had a diamond
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