Can anyone identify what probable kind of a fan/clutch arrangement I have? Conditions are: Cold/not running - blades turn easily by hand. Hot (220F)/not running - Same. When hot(220F)/running - tried stopping fan with rolled up newspaper in case it was just coasting, but it chewed the paper -- looked to me like it was being driven with good force. Jeep, 1987, Wagoneer LTD, 4.0. Islander.
Do you also have an overheating problem? Replace the clutch. I love your paper test, but it takes more power to move sufficient air for your cooling requirements than it does to chew up a newspaper. ;o)
Earle
Just a heads up.
You will get more responses if you post in a format everyone can read. Lots of folks here are on mainframes or just plain don't use windoze so your HTML posts show up blank or so full of code symbols they are not readable.
If you change you formatting or composing to 'text only', then everyone can see it.
I test a fan clutch by heating up the engine good and watching the fan when someone shuts off the engine. If the fan keeps on spinning after a hot shutdown, it is toast. It should stop almost immediately.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sIslander wrote:
You can also rely on the "100,000 mile" test and the "ten year" tests. This is a disposable, maintenance item type of part, not meant to last. Just replace it if you get suspicious...
Earle
"If you change you formatting or composing to 'text only', then everyone can see it." Thanx for the heads-up & advice. Islander.
Would the symptoms of a burnt fan clutch include overheating? When I replaced my fan clutch it seemed like the temp gauge ran slightly lower (maybe a 1/16th to an 1/8th). Does anyone have any idea how many MPG a fan clutch actually saves? I'd imagine Chrysler didn't put it in there for nothing.
-Bill (remove "botizer" to reply via email)
Exactly
Probably none. I suspect that its main utility is to facilitate faster warm up of the engine and thus reduce hydrocarbon emissions. A cold engine is a polluter, and a warm engine is less so. This isn't such a bad deal for the consumer either. A warm engine experiences less friction than a cold one, wears out slower, and prevents harmful water build up in the oil. When you are moving along at highway speed, the fan isn't doing much work anyway.
Earle
Earle, you're old enough that you should remember when they started using the clutched fans. The first one I ever had was on a '57 Ford and pollution was not an issue. AIR, the original claims for milage were fairly small but noticable - something on the order of 1-2 mpg (when gas was $0.25/gal) - but the emphasis was not so much on the fuel efficiency as on the benefits gained as the higher reving V8's hit the street. Noise levels were certainly a factor at highway speeds and that unsightly hole in the hood when a fan let go at high speed was not insignificant. The use of the clutched fan pretty well coincided with the increased availability of air conditioning as well. The fan pitch required to push enough air at low RPM needed to handle a/c made it impractical to run at high RPM - sounded like a freight train and had a nasty tendency to either sling blades all over the place or pull the fan into the radiator. Fuel efficiency gains, small as they were, became a more significant factor a only when the gov't started the CAFE program and gas prices started to rise.
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