fan clutch question....

[Odlaw]

About once a week my fan clutch engages when I first crank up in the morning (ambient temps around 80 F) and stays engaged while I drive the 9/10ths of a mile down my driveway running about 10 mph. It always disengages before I reach the highway. Anybody else experiencing something like this?

Back in the day when I drove a tow truck my old 94 F450 PowerSmoke would do this every day....was really annoying.

Thanks
Smitty

 

[Grendahl]

That is normal. My truck does the same thing.

 

[BoostN]

About once a week my fan clutch engages when I first crank up in the morning (ambient temps around 80 F) and stays engaged while I drive the 9/10ths of a mile down my driveway running about 10 mph. It always disengages before I reach the highway. Anybody else experiencing something like this?

Back in the day when I drove a tow truck my old 94 F450 PowerSmoke would do this every day....was really annoying.

Thanks
Smitty

Yep, completely normal.

 

[Odlaw]

That's what I was hoping to hear - thanks for the quick response guys.

Smitty

 

[Mad Maxx]

Mine does it too.

 

[BIGR]

Mine does it also. Sounds like its about to take flight.

 

[THEFERMANATOR]

Yep, normal. I've got an HD fan clucth on mine and I think it helps to pull itself down the road for the first mile or so.

 

[Odlaw]

Yep, normal. I've got an HD fan clucth on mine and I think it helps to pull itself down the road for the first mile or so.

lol, that's one way to improve fuel economy.

 

[THEFERMANATOR]

lol, that's one way to improve fuel economy.

Not really, I think it pushes enough airflow through the engine compartment that it lifts the hood up some. And I don't even have the new style 06+ DMAX fan that is even bigger and more efficient.

 

[btfarm]

That's been like that on my '03 8.1, '05 LLY, and the LBZ. I believe it used to be referred to as "morning sickness".

 

[THEFERMANATOR]

That's been like that on my '03 8.1, '05 LLY, and the LBZ. I believe it used to be referred to as "morning sickness".

ALL fan cluthces functioning properly should do this actually. A fan clutch uses a viscous clutch, and that viscous clutch fluid is pretty thick when cold. Until you drive far enough for it to warm the fluid, the fluid is thick enough to hold the clutch even with the thermal valve open.

 

[Odlaw]

ALL fan cluthces functioning properly should do this actually. A fan clutch uses a viscous clutch, and that viscous clutch fluid is pretty thick when cold. Until you drive far enough for it to warm the fluid, the fluid is thick enough to hold the clutch even with the thermal valve open.

yeah, I knew why it did it, just thought it was weird that it only does it about 1 day a week.

 

[RI Chevy Silveradoman]

Mine does the same thing, and usually does not engage until I hit about 35 mph, then releases. That fan does throw a lot of air!

 

[WarWagon]

"Morning Sickness" depends on the position the clutch stopped in and if it was locked in or not before engine shutdown.

Position: some positions leak more fluid into the working chamber when off - locking up the clutch for the next cold start.

Hot shutdown - well the clutch was locked in when you shut off the engine and it will stay that way - until a few min after start-up slinging the working fluid out of the chamber.

 

[schulte]

It's a good thing. Helps warm the engine by putting a little load on it :hihi:.