I posted a few weeks ago how I thought my fan clutch was stuck...well, only if I run the A/C does it stay on constantly even on the freeway..but if I don't run the A/C it won't even run. Is there a bypass I can do to cut it off or come on very selectively? Such a drag when I run the A/C and my mileage sucks...

 

What fan are you talking about?
The electric one in front of the rad?

 

Yes it seems it run sway too often when having the A/C on. It immediatly turns on and runs until I shut off the A/C and then some.

 

a/c condenser fan .......suppose to do that

 

Yep, and don't worry it's not robbing any power that you would notice.
btw It does not have a clutch and is not for cooling the motor.

 

Doesn't rob power my butt....truck can't even move hardly when it is on. I guess it's a faulty design.

 

may have something to do with your a/c check idle up setting and hoses for leaks

 

That fan is there for the sole purpose of cooling your condenser when your a/c is on. Its not the fan that is robbing power. When your a/c is on, the compressor is being turned by the crank shaft via a belt. That where your losing your power. Thats why high end drag cars run an electric water pump, no power steering and alternator disconnects. Its for less power loss. Thats if they even run coolant

 

If it's not the fan that's robbing power, then why when I turn OFF the A/C the fan still roars and I lose power?

 

Does it really take rocket science to explain why a fan running can pull horsepower from the engine?

The fan roars and you lose power when you turn the AC off because it runs until the pressure in the AC high-pressure side drops enough so the fan is no longer needed. In the mean time, it draws power from the electrical system of the vehicle and the alternator controls that so... more power draw means more alternator output is required which in turn means more drag on the engine.

Common sense, not rocket science.

 

I understand that, but what you missed was it stays on long past shutting A/C off and I was wondering if that wasn't normal.

 

Best I can suggest is hook a high-pressure a/c gauge to the system and see how the a/c pressure is while the fan runs. It may be a delay built into the fan switch that keeps it running for X minutes for all I know.

 

Do you actually see the electric fan in front of the rad run when you turn off the A/C, or do you just hear the roar?

 

Actually not finding a condenser fan at all on my truck, what I am hearing is the main engine fan in fact. Like maybe it didn't come with A/C from the factory and someone added it later...i don't know, it looks factory though.

 

At the beginning of the thread you said it was the electric one.

Sounds normal, don't think truck has the problem.

 

Yeah I couldn't tell at first, I'd rather have a smaller electric fan running than the engine fan taking all the power and sucking the mileage off. You would think a 4 cyl engine like these would have 2 fans as to reduce drag.