Cooling Fan Doesnt Shut Off

[Aaron.M]

I have a 69 Dart 340 I just picked up. It runs and drives but as soon as the engine fires up, the fan runs and doesnt shut off. It looks like a clutch fan. Do these go bad and just need to be replaced over time? It's been sitting for 15 years in a shop but I'm not sure how long it sat for it's previous owners before that.

 

[toolmanmike]

Yes the clutches can go bad. They will spin a bit when they are cold but should almost stop when they get warmed up 10 min. or so. If it roars and won't settle down you need to replace it.

 

[RustyRatRod]

It's normal for a belt driven to run until you shut the engine off.

 

[toolmanmike]

It's normal for a belt driven to run until you shut the engine off.

Exactly! But not be locked up and roar. The fluid in the clutch will make the fan spin at a low speed. It is a fluid coupler like a torque converter for a automatic transmission.

 

[RustyRatRod]

Exactly! But not be locked up and roar. The fluid in the clutch will make the fan spin at a low speed. It is a fluid coupler like a torque converter for a automatic transmission.

Yup, very similar.

 

[Dana67Dart]

The fan will spin with the engine running when cold but not at the same speed as when the engine is hot.


Can you spin the fan by hand when the engine is cold and not running?

As the airflow through the radiator heats up, the fan should be harder to spin by hand, with the engine not running.

IMHO if the fan is hard to spin by hand when the engine is cold the thermostatic clutch would need to be replaced.

 

[RustyRatRod]

The way I read it is, he is saying when he starts the engine, the fan never stops. That's the way it's written. This is normal operation for a belt driven fan. It will not stop until after the engine is cut off.

 

[Aaron.M]

Thanks guys. Sounds like it's normal for it to run while at an idle with a cold engine. I havent driven it yet so I'll see if the fan speed kicks up when it's hot.

 

[Dana67Dart]

Post some photos of your new find.

 

[Aaron.M]

Post some photos of your new find.

340 4 speed.

 

[Dana67Dart]

Very nice, looks largely rust free in the engine compartment