Heegoogoo1

Hi, does my cayenne coupe 2021 model keeps circulating oil and water even after the engine is shut down for cooling? Or its only the cooling fan ?

Thanks .

Schnave

The oil pump is mechanical, so no oil circulation after engine is shut down. However, the engine utilizes the electric fan and an auxiliary electric water pump for post-shutdown cooling. Excerpt from my post in this thread. (V8 pictured — Similar system in V6’s)
https://rennlist.com/forums/cayenne-...room-temp.html

​​​​​FAN
The noise is coming from the engine compartment purge fans (AKA radiator fans). If the ignition was switched off at an engine compartment temperature > 113° F (45° C), the DME control unit enters an “extended motor control unit run-on” mode for up to 25 minutes. Outside air is sucked through the front grill into the engine compartment. During this cooling, note that your horizontal active cooling air flaps in the center grill are open while the vertical side grill flaps (used for turbo intercoolers) are closed. The center flaps will close once the fans shut off.



WATER
One other thing making noise — an auxiliary water pump to cool your turbochargers. Oil-cooled turbos typically require a 3-5 minute cool-down prior to engine shutdown, since the oil stops when the engine stops. Manufacturers realize this is impractical and have adopted water cooling for turbochargers. While many use passive post-stop circulation called thermal siphoning, VAG uses a 12V after-run coolant pump to provide 132 gallons per hour of positive water flow after shutdown. The pump will typically run 10-45 minutes after shutdown and you may hear a humming noise during this time.

Heegoogoo1

Thanks, very helpful information, but my grill never closes back even after the fan is off.

thanks again.

Schnave

Hmm. I don’t think that is normal; you may wish to have that checked. Unless . . . maybe your Cayenne’s grill flaps are coded differently since it was delivered in Kuwait. I remember how hot it was at Ali Al Salem Air Base. Maybe the flaps are coded to always stay open in hot climates.

Heegoogoo1

Yer you are correct only in summer they stay open ,in winter they close .