engine cooling fan on after most drives

[morebhp]

I drive a 2004 996TT Cab and live in the south of Spain. Its about 30 degrees C most days at the moment (about 88 degrees F for those the other side of the pond).

I have noticed after pretty much any drive this time of year (hard and easy drives) the fan is starting shortly after I stop the car and running for a while.

It this normal?

Heres a few World Cup fun photos - http://www.facebook.com/album.php?aid=185921&id=633627862&l=1a4f0430ce she makes a Great Spain Flag! It was not driven like this!

All help appreciated

Cheers

Paul

[pierre]

Hi Paul,

We currently have the same sort of temperatures right now in Switzerland, up to 35°C... ;)

Yes, it's absolutely normal that the fan starts spinning the way you describe. Nothing to worry about.

Greetings

--Pierre

[Sunnyside]

Hi Paul,

Yes , it even happens here in Loch Lomond Scotland.

I wish more often. LOL

Frank.

[morebhp]

:-) hope you fan gets busy more often this summer Frank

[Danyol]

Very normal, sometimes even in the winter for me when I return to the garage and close it up. Car stays "alive" over 20 mins or so, fan goes on and off during this period. Summertime I go back to check as this makes me chuckle (i'm a tech geek)

Edited July 16, 2010 by Danyol

[Loren]

Very normal, sometimes even in the winter for me when I return to the garage and close it up. Car stays "alive" over 20 mins or so, fan goes on and off during this period. Summertime I go back to check as this makes me chuckle (i'm a tech geek)

Are you folks doing the Porsche recommended cool-down for turbos?

[Sunnyside]

:-) hope you fan gets busy more often this summer Frank

:thumbup:

Frank

[Danyol]

Very normal, sometimes even in the winter for me when I return to the garage and close it up. Car stays "alive" over 20 mins or so, fan goes on and off during this period. Summertime I go back to check as this makes me chuckle (i'm a tech geek)

Are you folks doing the Porsche recommended cool-down for turbos?

YES, 2 minutes

[pierre]

Are you folks doing the Porsche recommended cool-down for turbos?

Mostly useless. If you stop immediately after a hard drive, then yes. 30 sec to 1 min. But otherwise, I doubt you drive into your garage or parking slot at full throttle with the turbos spooling at full speed, huh? I guess that at least the last 2-3 minutes of your re-entry flight were at a rather low speed that didn't spool the turbos at all.:drive:

[Danyol]

Interestingly there have been those (a certain turbos expert) that have measured turbo housing temps at various stages of idle that still recommend 2 min cool down. I do take into account my "re-entry" speed prior to the stop (lights, neighborhood ect) but rarely turn off before 30 - 60 seconds (5 minutes at the track).

[morebhp]

Are you folks doing the Porsche recommended cool-down for turbos?

Mostly useless. If you stop immediately after a hard drive, then yes. 30 sec to 1 min. But otherwise, I doubt you drive into your garage or parking slot at full throttle with the turbos spooling at full speed, huh? I guess that at least the last 2-3 minutes of your re-entry flight were at a rather low speed that didn't spool the turbos at all.:drive:

Like the answer - makes a lot of sense - reminds me of a time when I had just bought a brand new Yamaha R1 1000cc sports motorcycle and I asked Clive Padgett (Team owner of the team which won all 5 Isle of Mann TT Motorcycle races this year) "Clive in these days of high accuracy engineering do I really need to run this R1 in" - his reply was a classic - "Paul, with all due respect you will always be running it in" :thumbup:

[OscarAH1W]

Paul- More nerdy-numbers for you from Adrian Streather's great book on the 996. In the 996 turbos, the fan comes on in 3 modes:

1: Ignition on or engine running: Turns on if booster resistance cable detects a buildup of heat from exhaust system.

2: Coolant temp of 105 deg C or engine bay temp of 78 deg C: Runs until engine bay temp below 40 deg C.

3: (I think this is where we all notice it) Ignition off/Engine bay temp greater than 25 deg C (system "armed") and temp rises over 78 deg C for more than 3 min.: Enters after engine shutdown protection mode. Fan runs until temp drops below 78 deg C; system monitors engine bay temp every 10 seconds for 40 minute cycle, running fan as necessary to get below 78 deg C. After 40 Minutes, system shuts itself off.

As for the cool down comments in the thread, I think Loren addressed it in a previous thread regarding the puff of white smoke some owners see on startup. If I let mine idle a bit prior to shutdown, I don't get it... If I don't, it farts. I'm surprised I don't see more turbo timer discussions if this is an issue.

I purchased the book on Amazon, if anyone is interested. It is a British-published book, so should be widely available on your side of the pond!

Cheers,

Oscar