Engine Fan Staying On...

No damage, but a proper operating system needs no help !!!!!

 

Thanks. I am doing it for just to avoid over heating,other than engine runs about 200F with heavy load going up hill.with out the fan on.

 

if your fan sensor system is operating properly, you are just wasting fuel by running the fan more than the system really needs.

 

and 200 degrees is nothing nowadayz !!!!!!!

But honestly, lots of us turn it on manually, no biggie !!!!

 

I know its a waist of fuel to keep it on much. During the 90 deg. plus days here I keep it on in traffic to keep the air moving under the hood. I would think it would help the alternator, sensors, and a/c parts keep cool. Before it put a switch on I would go through two gallons of oil in 15k miles now I'm down to one. When the fan is on I don't get above 1400-1500 rpm's. It also keeps the fan off when traffic clears, it will stay on for miles of the ecm cycles it on.

 

congrats tkilby. sounds like your shop knows what they are doin.

 

I have a 97 Pete with a cat and all of a sudden the engine fan started to stay on! I have changed the air switch on the fire wall and have noticed that it has constant power? The switch is suppose to be normally closed according to Peterbilt? I have talked to Peterbilt and they told me to change the way it was plumbed to normally open still not working? I have jumped the high pressure and let it run for 45 min and still runs, could this just be the manual switch in the dash? i am going to change the relays and try to figure out why it has power all the time?

Thanks Dan

 

Which switch is the high pressure switch I have 2 on the ac one is blue and one is red I take it the red is high pressure .

 

Yes Red is high pressure side and blue is low another is size red diameter is bigger so bigger cap fits on it then lower pressure side.