Fan...tastic (FAN QUESTION)

[Guest]

Just to fill people in... my earler post relating to a MAF sensor was ok today by a porsche specialist... but i'm now panicing over the fan... below you'll find what I posted on my MAF sensor post.

Any advice would be greatfully appreciated...

Right guys... heres the analysis.... car was found to be OK... after the check over at the specialist (it was just me []) yes, you can all laugh at me now!

BUT, and it is a BUT! whilst driving home the 20 miles from the garage during the rush hour... after 10 mins of good driving, I had the pleasant experience of being sat in traffic, never noticed until about 10 mins into this traffic that my temperature gauge had reached something in the region of about 92 (needle pointing at the right handside of the zero of the 80 mark or a mm past it, when it normally fluctuates around 82 or left hand side of zero on the 80 mark...) obviously once i began moving briskly it naturally dropped slowly back to its normal area.

Is this the norm... Porsche Guru aka Richard do you have any answers..? Guys, any thoughts?

Once home I sat on the drive with the spoiler raised to see whether the fan would kick in, again it reached 91ish after 10/12 mins but the fan failed to kick in,.... at what temperature does it kick in? (at this point the down pour deterred me any longer staying outside, and could not be bothered to move cars around to put it in the garage... hence why Im on here seeking some advice (again)

NOTE: THE FAN IM REFERRING TO IS THE ONE ON TOP THE ENGINE BAY/LID.

How often do the front fans kick in? what temperture?
Any checks etc...?

God, i'm beginning to break into cold sweats over this now.... or is this a case of LAUGH AT ME AGAIN?

I appreciate any help...
Cheers
Chris

 

[Richard_Hamilton]

Chris

DON'T PANIC. I don't think you are experiencing anything abnormal. It has taken me a while to find it, but here is what the workshop manual says about the fan cut-in conditions:
Switch-on conditions for coolant or condenser blower motors: Stage 1 is switched on when the coolant temperature is >100 °Corthere is an A/C 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 °Corthe refrigerant pressure is >16 bar. Switch-on conditions for engine compartment fan: The engine compartment fan is switched on when the engine compartment temperature is >80 °Corthe coolant temperature is >102 °C. After-running of engine compartment fan If the ignition is switched off and the engine compartment temperature is more than 60 °C, the DME control module remains in readiness for another 20 minutes. During this time, the engine compartment temperature is retrieved every 10 seconds. If the engine compartment temperature is >85 °C, the engine compartment fan is switched on for 20 seconds. If the engine compartment temperature is still >85 °C after this time, the fan remains on for a further 30 seconds. 80 degrees C is a very high temperature to be inside the engine compartment. Also, the light on the temperature gauge would flash if the compartment is too high. The front fans won't come on until the coolant temperature gets up to 100 (or if you have the A/C on and a power supply [terminal 15]). I don't think the gauge reading is too high as a result of stop-start traffic for 10 minutes. Edit: Typo correction - "coolant OR condenser blower motors"

 

[Peter_Bull]

What an excellent reply Richard. You are truly a genius and a real help to us all.

PS Don't move on to a 997 just yet please!!

 

[Guest]

(Wiping the sweat from my brow) Thanks Richard... thats great news... but alas - the car is going back in tomorrow for peace of mind!

This is becoming quite expensive for something that isn't wrong!

Thanks Richard... I think I speak for us all when I say that you an expert of these matters and a great help!

 

[Guest]

So what happened yesterday wasn't abnormal...?
Normally the highest i have ever seen was 85... will all 996's react like this and creep up? Would leaving the A/C on improve cooling - as far as im aware dont the front fans come on in conjunction with the A/C?

 

[Richard_Hamilton]

No it's not abnormal, and yes the fans will come on if there is an A/C demand. The fans running at stage one are fairly quiet, so you might not hear them in the cabin. You will hear them roaring when they switch to stage two.

I wouldn't worry unless the gauge reads over about 90 under normal driving conditions (ie not stuck it traffic), or the light is flashing. If it does read high when driving, it is probably something simple like the thermostat not opening fully. Remember that the water is not going to boil at 100, as it is under pressure.

 

[Guest]

Thanks Rich []

 

[Guest]

Last one... honest[] By keeping the AC on, will it ensure the engine temp will remain more normal as the fans are on? As I normally keep the AC on... i think yesterday was a rare time when it was generally left off.

Thanks again

 

[Richard_Hamilton]

I'm not sure, because I don't think there will be any demand for aircon if the outside temperature is lower than the cabin temperature.

 

[Guest]

Well after a hefty test with a/c on the car remained a constant 82... this was during normal driving, fast driving and of course leaving it simply idle.

So all is well... i didn't take the car back based on all this information - thanks again Rich!

So, i'll stop worrying and just enjoy the car............ well, stop worrying for now!

 

[C4S al]

Hi Chris,

This is where you are hiding!!!

I always keep my aircon on all year round. It apparently stops the seals from drying out and less hassel than being kept switched off apart from the 3 days in the summer when we need it!

Also in winter with the aircon on it will demist the windows quicker due to the vapourisation process.

Missed you Saturday, we had a good run out.

Cheers Alan.

 

[Ian W]

Just to add my 2p's worth...

Yes, it is absolutely normal for the temp to creep up a little in stop/start traffic with the aircon off. Yes, with the aircon on, the main fans on the rads are continually running in slow mode so the temp won't creep up as much. I agree with everything said in previous posts.

One thing to add though. The aircon condensers and rads get chock full of debris over time. In particular, the space between the condensers and rads can become blocked with leaves, sweet wrappers, all sorts of stuff!! Once this build-up of detritus gets too much, your temperatures will begin to soar which is not good for your engine. Have the rads cleaned out at least once every couple of years. (Front PU off, ducting off, release the condenser mounts and blow/vac as much out as possible - it's been documented quite well elsewhere on here).

Hope this helps

 

[Guest]

Hi Alan... yes I know... im a bit disappointed but as you can see I had a lot on my mind - which turned out to be absolutely NOTHING!

Which isn't a bad thing - I must learn to relax!

Well Alan, let me know of any further events and i'll be there! If you want an impromptu drink and chat let me know... Friday night is always good for me as my other half is normally tied up with paper work. (The pain of being a teacher - i did tell her)

Thanks Ian for the advice... great to know that others have experienced this, i'll make an effort one day and undertake the task of cleaning out any debris. Probably when it gets a little warmer