engine fan

[ricg]

Ok so i live in Texas and i know the temps are hot down here, but my engine fan kicks on when i start up my truck. Im reading my gauges and its showing 160-180 on ECT. Does this have to do with the A/C pressure?? I'm not loosing any coolant. any ideas?

 

[713Diesel]

I am in Central Texas and mine kicks on too. Does yours kick on immediately at start up? Mine kicks on usually after about 4-5 minutes after start up only if it is 95 and it is ideling or in heavy traffic and it is 95 or above. If it comes on any time other than that I don't notice it but that thing is LOUD so I figure I would notice it.

 

[ricg]

thats what mines does.. and when i get moving it will shut off.. so thats why i was thinking it had something do to with the A/C system and pressure??

 

[713Diesel]

I think it just gets to the coolant temperature that the fan is slated for to kick on. I imagine that running the AC does not help since I think it is dissipating heat with air moving from the fan through the condenser...... maybe I am mistaken though...... Once upon a time I learned how all the stages of AC systems worked but I can not recall exactly what is what.

 

[tbsimmons]

I have not looked at the schematic for the cooling fan operation. But I bet that one of the signals is from the high side pressure switch of the AC.
Higher pressure more heat needs to be removed.
That is why vehicles with electric fans have one turn on automatically with the AC, the other runs off of AC Pressure, Engine Temp, etc.

 

[Dzchey21]

Yes that's the a/c kicking the fan on don'tworry about it. You will notice the fan turns on more if you let the truck sit and idle with the ac on

 

[Dzchey21]

The pcm takes signals from the ac high side pressure to turn it on. These trucks don't have thermal fan clutch like the older trucks did. The fan won't even turn on until 220 degrees coolant temp

 

[ricg]

thats what i figured, but just wanted to make sure thanks.