Radiator Fans... What temp do they engauge?

[CJ_Boxster]

Hello again, I have 1 question, Do the radiator fans infront of the car turn on at a certain temp or only while the AC is on?

[Loren]

The radiator fans are two stage. The fans always go to stage two (fast) when the the AC is on.

They turn on as follows:

Switch-on conditions for coolant or condenser blower motors

Stage 1 is switched on when the coolant temperature is > 100 °C

or

there is an AC demand, the intake air temperature is > 8 °C and terminal 15 is switched on.

Stage 2 is switched on when the coolant temperature is > 105 °C

or

the refrigerant pressure is > 16 bar

[CJ_Boxster]

The radiator fans are two stage. The fans always go to stage two (fast) when the the AC is on.

They turn on as follows:

Switch-on conditions for coolant or condenser blower motors

Stage 1 is switched on when the coolant temperature is > 100 °C

or

there is an AC demand, the intake air temperature is > 8 °C and terminal 15 is switched on.

Stage 2 is switched on when the coolant temperature is > 105 °C

or

the refrigerant pressure is > 16 bar

Ok well all im looking for is Stage 1 to trigger, and heres what i got.

During Idle, ambeint outside temp at 61°F degrees... AC off.

Fans did not turn on until 103°C and remained on until the coolant temp lowered to 100°C.

Now Loren, whats all this mean? I got the °C reading from the Automatic Climate Control display section 6c incase your wondering.

[Loren]

What are you worried about - that sounds about right?

Is your car overheating?

[CJ_Boxster]

Well it bothers me that it is 3c off of when it should be triggering the fans, and also, someone also told me its suppose to trigger at 96.75 celcius rather than 100, my car is a 1997 2.5 liter motor......incase that makes any difference.

[Loren]

My quote above is directly from the Porsche service manual.

[CJ_Boxster]

Oh ok, then, I guess 3celcius off isnt too bad. Loren, what would cause it to trigger fans 3c late?

Remmeber triggers at 103, and disengauges at 100.

[Loren]

Do we know that the climate control measures that temperature at the same place as the DME?

Perhaps the climate control reads the temperature at the heater core inlet? and the DME reads it at the engine?

I may try to hook up my PST2 to my car and see what the DME temp says compared to the climate control.

[CJ_Boxster]

Interesting, I dont have a PST2, what if i hook up my ODBII scanner, will the scanner read temp from the DME?

[Loren]

Depends on the scanner... the Durametric Software will.

[CJ_Boxster]

Its a Solious...cost about $1500+

[Loren]

If it can show actual valves (from the DME) then you can compare - if not the Durametric software is only about $250 (vs. $3600 for a used PST2).