Norcalphoto

I was out driving for about 40 minutes today in 92 degree weather and when I got home and shut off the engine I noticed the fan in the engine compartment was running. No error lights on my dash and everything was fine while driving. The engine temp was just over 180 the whole drive. I parked it in the driveway in the sun. I've had other cars that have had the fan cycle on and off after a drive and with the car turned off? I'm just checking to see if this is normal for a Porsche. I thought I read somewhere that the fan will cycle on for up to 30 minutes with the ignition off but I can't remember where I read it. Any insight would be appreciated.

peteb3

Totally normal

Cuda911

^^^ Yep. Normal.

I think every person who buys a 996 wonders about that after their first drive or two.

Norcalphoto

Thanks guys! I've had a few other cars that have done this but since this is my first Porsche and car of any kind with over 100,000 miles I'm being extra cautious. I'm sorry to say this is just the first of many questions that I'll have.

996Ray

I have never heard mine run.......I hope it is functioning properly. Is there any way to force it to run without a Durametric to turn it on. Thanks, Ray

Torontoworker

Yes, pull the plug on the fan wire off and hook a 12v power supply up to it.

The controlling temp sensor for the engine bay fan is a small probe that is attached with a rubber grommet between the two closest intake runners on the passenger side bank. The sensor heat probe detects the ambient heat rising off the engine and the fan starts up using battery power (when ignition off) to run the fan until the preset temp (can't recall what it is) is below the threshold or x number of minutes since engine was running.

FYI: Durametric's can't turn the fan on or off - only tell you the engine bay temp's.

9964runner

So if the fan is running with ignition on, when the ignition is turned off should the fan continue running?

Ahsai

If memory serves, Durametric can turn the engine fan on/off. It can also turn on/off the radiator fans and SAI pump, and fuel pump, etc.

You can probably test the fan by using a hair dryer to blow hot air on the sensor. When engine is turned off, the DME still keeps monitoring that sensor.

Kazual99

Correct , you can turn on the engine compartment fan with the Durametric

Torontoworker

Not all ver's can do this. Only 6.0 and up can do this for 98-05 996's. Fault code for purge fan is P1675

From Renntech

Engine Compartment Purge Fan

To reduce the temperature of the engine compartment, a fan actuated by the DME control unit is installed under the ventilation grille of the engine cover.
If the fan is active, fresh air is fed into the engine compartment. The fan can only be actuated 100 seconds after the engine has been started.

Functioning

1- With engine running or ignition on:
If the engine temperature is higher than 102° C and the engine compartment temperature is higher than 60°C, the engine compartment fan is switched on for 30 seconds by the DME control unit and the engine compartment is thus ventilated.

2 - Engine compartment fan if vehicle is stationary and engine is switched off (after-running of control unit):
If the engine compartment temperature is higher than 60° plus C when the engine is switched off (ignition off) or if the engine stalls (engine speed: 0 rpm), after-running of the DME control unit lasting 20 min. begins. The DME relay remains active.

After-running of the fan continues until the programmed time has expired (20 min.) or until the next engine start after which the engine runs for more than 100 seconds. If the engine compartment temperature is higher than 84.75° C during after-running of the control unit, the engine compartment fan is started and runs for 30 seconds.

If, at the end of the operation period (30 seconds), the engine compartment temperature is still higher than 84.75° C, the engine compartment fan is started and runs for another 30 seconds, etc. If the temperature now drops below the threshold (84.75° C), a polling pause lasting 10 seconds occurs.

Note: If the engine temperature has not dropped below 80.25°C after the engine compartment fan has been running for 25 seconds, a fan fault is registered and the coolant level warning lamp is activated (flashes)."

Dstutler

In response to OP of where he read it - it's in the owner's manual.

trendy996

Take the engine compartment sensor off the manifold and lay it close to the engine while driving. That'll set the fan off. It will also cause your coolant warning light to flash bc it's indicating the compartment temp is to high. I removed my fan bc as some of you mentioned it hardly comes on. The stock gt3 doesn't even come with one if my memory serves me right.

Torontoworker

Depending on what your comparing - the GT3 engine (M96/76) is a highly modified vers of the M96/01 - M96/02 specs as found in the 99-05 C2 and C4 models and is much closer in design to the M94 then it is with the normal Carrera engine. (all sorts of cly treatment differences, material type changes)

There were all sorts of cooling changes incorporated as the car was homologated for racing based upon the equipment delivered as spec. A third rad was added up front, (59% more cooling surface) oil/coolant heat exchanger is larger then the 01/02 engine types, larger diameter exhaust (45mm) pipes and less back pressure from the cat's (shorter length and a new tri metallic layer) along with a different dry sump set up with a larger oil tank at the front of the engine all helped reduce heat in the engine bay and then there is that rear deck design that flows far more air into the engine bay for intake purposes and heat reduction. That's why that little fan getting in the way had to go and wasn't needed anyway. It's only required for a car that puts out 100hp less!! (Go figure.)

crashclint

I know this is an old thread but after searching it seemed the best place to post. It was 100 degrees today and I was in traffic a lot. Pulling into my garage the Engine Compartment Fan Failure came on but the fan was running fine. The engine compartment temp gauge looks to be in place. Running temp is normal, coolant is fine but one thing that seemed odd, the fan is pushing air out of the compartment up through the spoiler, shouldn't it be pulling air into the engine compartment through the spoiler?

Rubik

I've put my hand on on the spoiler a couple times while the fan is running and it's definitely pulling.