Yesterday was the first hot day I've driven on since my November ownership. I have always thought that the engine ran a bit hot but the guage ran too far to the right for comfort. The fans were making an industrial din I could hear over the X-piped RMBed sound.
Checked the flaps and the buggers were shut so there's a fault somewhere.

I believe that when the ignition is off then they should be open, and then will do a cycle test on startup?

Dan

 

I just unplugged that stupid flaps and manually opened them. There is such thing called a thermostat.
Steve

 

Model year?

 

Correct - should be open when ign off.

They just close when you turn the ignition on with a cold engine.

Quick solution is to unplug then adjust manually open (**** under the rubber cover over the flap motor on the pass side of the flaps)

 

Dan,

These flaps are an unnecessary complication. They apparently offer very a slight advantage aerodynaimically when going flat out but logic suggests they are more likely to be open when the engine is working hard.

Porsche deleted them on the GTS. On cars imported here the main agents disengaged the flap mechanism. On my late S4 we also removed the slats to help improve cooling air flow [a tip from Marc Thomas of Devek].

As long as thye work not a problem in the UK but if they do not then doubtless you will be in trouble on hot summer days. In fact I believe that the UK was hotter yesterday than Oman [but then we were hit by a tropical storm that dumped a huge pile of rain here]- the temperature dropped to about 25C- we even had some cold [coolish] water!

Regards

Fred

 

Thanks for the replies, folk.

Just checked them on cold start this morning and:

ignition off: flaps closed
ignition on: flaps fully open
engine running: flaps fully open
engine running, AirCon on: flaps partially open

Work perfectly but the wrong way round.
Something is reversed somewhere!

But where?




PS it's a 1990 928GT

 

you can manually open the flaps all the way and simply pull it's fuse.

 

I like the flaps on my S4's Faster engine warm-up, and its just plain cool that they also close to improve drag at high speeds.

 

as cwiert said get the flaps open then pull the fuse,
leave the connector connected it keeps dirt out of the connection

 

When I got my s4 the flaps had been disconnected from the actuating arm and cable tied fully open. The car came to me from Hong Kong and I guess they needed all the air they could get. I replaced the arm but then they fouled on the inside of the bumper broke the little crank that goes from the motor to the arm. If fixed the fouling issue etc and now they work well. I do kinda like them.

 

The flaps work perfectly, just the opposite way round...

I want keep them connected as its a great feature of the 928.

Is it just a case of reversing the polarity?

 

I doubt that the connector isn't keyed in some way to make it difficult to connect backwards. On the other hand, we all know the super-human powers of a PO.

My GUESS would be that the crank (928 575 053 00 - item 12 on PET illustration 105-06) on the shaft of the control motor is installed or connected incorrectly.

Installed 180 degrees out would make the flaps act exactly reversed without requiring the electrical parts of the system to be running backwards.

 

Take a look and see if you can take the motor linkage off and move the linkage so that the flaps are open when you replace it.

 

Done some further investigation and:

ignition off: flaps closed
ignition on: flaps fully open
engine running cold: flaps fully open
engine running, AirCon on: flaps partially open
engine running hot: flaps closed!!

Just can't work out why they work the opposite way they should.

I have removed the linkage and power then set them open, adjusted to correct position with the **** under the rubber then reconnected, and the motor rotates it all the way back to shut.
In fact it seems to constantly check: with the ignition off I can rotate the adjustor **** up to a point when it will suddenly spin and close the flaps!
And with ignition on, if I rotate **** to shut flaps it will kick in and shut them again.
I admire its ingenious ability to restore its own setting but wish it did it the correct way round.


Have now removed fuse and set to open, but would love to get to the bottom of this as a matter of principle.

Please help!

 

no real proof that they help drag at speed. in fact, with a hood vent, I would say its the opposite. even without it, the air only has to penetrate the radiator, and then travel under the car. them being closed, means the air has to bunch up , up front, and then go under the car. interesting drag analysis challenge though, but a rounding error in the entire scheme of things I would imagine.