Oldracerjones

Isn't the fan on a 1970 442 supposed to turn freely when the engine is stopped? I thought the fan clutch allowed it to rotate when the engine was stopped but mine does not move.

tru-blue 442

It should turn freely with
the engine off. If your's won't
it is locked up. Bad bearing.

OLD SKL 69

x2

Time for a new one.

tru-blue 442

I may have a used one in the stash
if interested. Of course it's used, may last
a long while or not. You never know
with the clutches in those.

Nop

If I may ask... I got a 350 with AC, a 5-blade (or 6? Definitely not a 4-blade) fan with shroud and I can also turn my fan with the engine off.

By "I can turn it", I mean I can move it with one finger when cold but it won't really rotate "free" and stops as soon as my finger leaves a blade more or less.

Hard to describe, it's not locked on the water pump shaft but when revving my engine it sounds and blows as if it has no slip at all.

Can anyone somehow describe how it's supposed to "feel" or are there any testing procedures? I already have a new clutch and I'm thinking about replacing it now or keeping it for later...

Thanks

nsnarsk65cutlass

If it's roaring when driving cold it's locked up.It should turn without too much effort or wanting to turn the pulley when turning by hand.Nick

MDchanic

Nop, you are describing the normal feel of a fan clutch.

It should roar and blow your hair back when first started, then settle down and blow less after a few minutes, then roar again if the engine gets hot (like sitting in traffic for a long time on a hot day).

- Eric

Nop

It's definitely not roaring, bearings of the water pump and the clutch seem OK. I was wondering why the sound of the fan goes up instantly when revving (still cold engine), although it has slip and is not locked up.

So it just sounds like it's running about 1:1 with the engine when cold. I'll check the sound difference when it's warmed up.

Thanks

MDchanic: Aren't hair comparisons here forbidden by forum terms and conditions?

MDchanic

The clutch function sounds okay.

When it's cold, the fluid inside is thick, and it engages more than it should, then the fluid warms up and it settles and works off of its thermostatic valve. As the valve gets hotter, the clutch tightens up, as it cools, it loosens.

- Eric

Miles71

Great tips, Ill check mine this spring when the snow melts and the chemicals wash away.
I am still running the factory original clutch (350 4bbl, with AC, Shroud, 3-core-orignal).
I have noticed that on an 80F day, in traffic with AC on, the engine temp will hit 210+F.

Cold morning first start, fan will spin almost 1:1 (at idle)
Engine warm, not hot, fan will spin slower than water pump shaft.
Engine Hot, on a Warm-Hot day, fan will spin almost 1:1 (at idle)
Is this correct?

tru-blue 442

Miles, it sounds like yours
is going South. Do you notice
any slung looking oil on the back side
of the clutch or fan blades on the engine side?
These are good indicators that it is loosing it's oil.

Also Nop, I agree with Eric. Yours is working as it should.

Miles71

[QUOTE=tru-blue 442;663023]Miles, it sounds like yours
is going South. Do you notice
any slung looking oil on the back side
of the clutch or fan blades on the engine side?
These are good indicators that it is loosing it's oil.

Hi Tru-Blue:
I have not noticed any oil leaking issues in that area, however I will take a closer look at the clutch shaft the next time I start the car.
I will assume that my original radiator is on its last legs. The previous owner did not change the radiator fluid for 20+ years.
I have flushed the radiator a few times in the past 24 months.

tru-blue 442

Miles, another indicator, if
you can grab hold of the fan
on both sides and wiggle it back
and forth a little, the bearing is
going bad or it has lost a good bit of it's oil.

This could also be a bit confusing though if
a waterpump bearing is going bad. But if that
was the case, you would see the pully wiggle
with a bad pump bearing.

oldcutlass

In most cases, no funny noises, no wiggling, no leaking fluids, and not overheating = good.


I don't have enough hair on the top of my head to perform the above scientific test.

Oldracerjones

Thanks guys, that's what I thought.

Koda

I have used the "it should rotate a few inches when spun by hand hard" test when engine is cold.

Funny thing is I have a AC 442 67 that does NOT have a 6 blade clutch fan. I did buy a used one to put on, but right now it has 4 blade no clutch.