fan on with airconditioning question

[nukegm]

comrades! my 18 6.7 fan normally comes on at 206 degrees. however when i run the air conditioning, the fan comes on at 190 degrees. is this normal?

thanks in advance for any replies. cheers!

 

[TCDiesel]

Yes.. The New Programing has coolant and evap/condense programing, either event will cause the fans engagement, You may experience engagement at any time under certain conditions.

 

[Cummins12V98]

Never had mine come on under 200. Towing heavy with AC.

 

[MConyers]

My fan seems to run intermittently in warm weather with the AC on, unlike previous trucks. Sounds normal to me.

 

[JR]

Completely normal operation. All vehicles operate this way, at least ones that have electric controlled fans. Without air being pulled across the condenser your a/c performance would be poor. Many (especially older) vehicles are simply on/off or on/low/high speed, but in our trucks case I believe the ecm controls the fan speed based on refrigerent pressure, among other parameters.

 

[kthaxton]

Yeah, perfectly normal. AC won't work well at all without airflow across the condenser.

 

[Tuesdak]

The upper limit of AC is a condenser temp is 160 degrees with R134a or 300 Psig. Cold air out the dash falls off and Psig rises quickly over that. The fan starts to come on in the mid 200's for Psig and as mentioned this is independent of engine temperature. Sometimes you get enough ram airflow to keep the condenser cool without the fan.