engine temps in Southern Cal?

[CJ_Boxster]

Do the radiator fans in the front of the car turn on when the car reaches a certain temp or do they only turn on when the AC is turned on?

[subgraphic]

My needle stays on the 8 in the 180° mark, no matter how hard I drive...

[CJ_Boxster]

Originally Posted by subgraphic

My needle stays on the 8 in the 180° mark, no matter how hard I drive...

Do you ever hear your radiator fans infront of your car turn on while your AC is off?


I called the Porsche Service and they told me that they are suppose to click on in the 180 range...estimation*** and also if the AC is turned on, They said it im reaching the 190 to 200 range without them turnin on, then he said something is wrong... They also said that the fans have 2 stages... regular and high...I guess they will spin faster if the car continues to get hotter.

[MNBoxster]

Originally Posted by CJ_Boxster

Do the radiator fans in the front of the car turn on when the car reaches a certain temp or do they only turn on when the AC is turned on?

Hi,

The Radiator Cooling Fans have two different speeds and are controlled by the DME. The operation of the Fans, or the selection of the Fan speed, is not temperature dependent alone. The DME uses several other variables to determine the Fans operation.

These include: Ambient Temperature (determined by Intake temperature from the integral Temperature Sensor in the MAF), Driving Speed (from the Wheel Speed Sensors, to judge the airflow through the radiators - another reason why keeping the Radiators clean is important), Engine Speed (to judge the vol./time of the Coolant flow - Coolant Pump flow is rpm dependent), Immobilization time since "Ignition OFF" (to judge heat buildup), AC Refrigerant Pressure (from the AC Pressure Switch, to judge load placed on Engine, affecting Engine Speed, especially at idle).

So, you cannot judge the proper operation of the Fans by the Temperature Gauge alone. In one instance, at one displayed temperature, the Fans may operate, or may operate on either High or Low. In another instance, with the same temperature displayed, the Fans may not operate at all, or may operate at a different speed.

For example, at idle, say at a Stoplight, the Fans may operate on High speed at Coolant Temperature X, while at 65MPH, at that same Coolant Temperature X, the Fans may operate at Low speed, or may not operate at all. There is a Temperature Default in the DME software which will override the other variables given the following conditions:

The Fans will always work on Low speed: When the AC is switched ON, or if the Coolant Temperature exceeds 96.75°C (206.2°F).

The Fans will always work on High speed: If the Coolant Temperature exceeds 102°C (215.6°F), or the AC Pressure Switch is CLOSED (when Refrigerant Pressure exceeds 16 bar or 232 PSI).

The caveat here is that the Fans may indeed work in the Default Mode, but due to a failed or failing Switch or Sensor, may not work optimally under normal driving conditions. This may account for some of the varying operating Coolant Temperatures some owners report having, but there are so many variables involved, that it's impossible to say for sure.

Hope this helps...

Happy Motoring!... Jim'99

[CJ_Boxster]

Originally Posted by MNBoxster

Hi,



The Fans will always work on Low speed: When the AC is switched ON, or if the Coolant Temperature exceeds 96.75°C (206.2°F).



Hope this helps...

Happy Motoring!... Jim'99

THanks, this is the peice of information i was looking for, When i get home Ill let my car idle for awhile until it reaches 96.75 cel and see if they turn on at all. Cause i dont ever recall them turning on at all UNLESS i turn the AC on. Thanks Jim

[MNBoxster]

Originally Posted by CJ_Boxster

THanks, this is the peice of information i was looking for, When i get home Ill let my car idle for awhile until it reaches 96.75 cel and see if they turn on at all. Cause i dont ever recall them turning on at all UNLESS i turn the AC on. Thanks Jim

Hi,

Be sure to read my ammended post, because even though the Fans come ON in the Default Mode, doesn't mean that they are necessarily operating properly outside the Default parameters. The only 2 things which the Default Mode really tells you is that the DME is recognizing the Default parameters, and the Fan Motors work. Hope this helps...

Happy Motoring!... Jim'99

[CJ_Boxster]

Originally Posted by MNBoxster

Hi,

Be sure to read my ammended post, because just because the Fans come ON in the Default Mode, doesn't mean that they are necessarily operating properly outside the Default parameters. The only 2 things which the Default Mode really tells you is that the DME is recognizing the Default parameters, and the Fan Motors work. Hope this helps...

Happy Motoring!... Jim'99

Ok, got it, Im just worried weather not they are turning ON at all when the AC isnt on...cause sometimes i know i get really high temps in slow traffic on hot days but all i hear is the engine fan turn on. but never the radiator fans, I just would like to see if they trigger Low Speed at least when the temps reach over 96-97 celceius at a stand still...

[CJ_Boxster]

Ok Jim,

Heres what i learned...

My radiator fans will not turn on at 96 celcius, They turn on at 103, and stay on until the coolant temp reaches 100. If it matters, the Ambeint outside Temp was at 61 degrees.

Why would the fans turn on so late? i checked them twice, during idle they will turn on only at 103 celcius until temp goes down to 100 celcius. Can the dealer program it to trigger at 96.75?

[MNBoxster]

Originally Posted by CJ_Boxster

Ok Jim,

Heres what i learned...

My radiator fans will not turn on at 96 celcius, They turn on at 103, and stay on until the coolant temp reaches 100. If it matters, the Ambeint outside Temp was at 61 degrees.

Why would the fans turn on so late? i checked them twice, during idle they will turn on only at 103 celcius until temp goes down to 100 celcius. Can the dealer program it to trigger at 96.75?

Hi,

If I had to guess, and this is essentially what I'm doing, I'd say that either your Coolant Temperature Sensor or your Cooling Fan relays are showing their age and not operating at 100%. The Software in the DME didn't suddenly start looking for 103°C instead of 96.75°C. Ambient Temp would have nothing to do with the Default Parameters, though it would with normal operating ones (1 component the DME uses).

We're only talking about 6°C here and that could well be within any innacuracies of the Temp Sender or the Gauge or Climate Display. It's not affecting anything. I doubt the MAPs are affected, nothings going to melt, you're not creating appreciably more emissions or suffering any reduced performance. I think you're just obsessing. But, if it bugs you that much, start by cleaning the radiators, replacing the Fan Relays, and changing the Coolant, and see what effect that has on the readings. Hope this helps...

Happy Motoring!... Jim'99