silentbob1234

Just got a new base 718 Cayman.

I am starting to notice a humming noise that tapers off after 3 seconds always after the engine is shut down. It is loud enough to hear through the door.

This noise is generated from maybe in between the intake and drive side door?

Things that I have read are either the cooling fan, Evap system or fuel depressurization.

Anyone else experience this?

ldamelio

Cooling fan will run for longer than that after the car has been run hard FWIW.

silentbob1234

I heard the cooling fan turn on before...this sounds like a farting (I am serious) hum...

spdracerut

Heat exchanger for the coolant for the air-water intercooler sits over there. Could be the coolant pump winding down.

Leicht

Hahahah, Occasionally I have this noise too...like slow humming/farting noise with tapering volume.

silentbob1234

Thanks for all the replies,

After looking through the schematics, like you guys, I suspect it is the auxiliary water pump winding down for the intercooler...I didn't even know there was three water pumps on the 718. I though I was going crazy.

I went for a drive for a couple hours, engine temp. are stable at 90 Celsius, oil temp is at 104 celsius (non sport mode), and no unusual noise with the window down or in the cabin. Just that tapering fart/hum when the engine shuts off for 3 seconds.

As someone new to Porsche, i am going to threat it like a Harley...might make a lot of unusual noises but if it doesn't effect performance, not louder than a running engine, and no check engine light, then ignore it.

Optical TDI

I have same noise. Thought maybe a fuel pump but looks like you figured it out. Glad to hear it’s normal. 👍🏼

Ricard

Same here with my Boxster 2016 do you know what was that noise now?

gcurnew

Currently on Porsche #4...all have made noises and emanate smells other cars don't (although current 992 is the least smelly of the lot). It's part of the experience.

Lou DeFino

I've heard that too. Pretty funny!

.2PDK

If I return home and hear nothing on shutdown I haven't driven it properly.

fantom

I know it's a base engine, but ya still gotta use 93 octane.

msacks

Both Porsche Dealership and Indy Mechanic told me its the Wastegate on the turbo bleeding off pressure, perfectly normal for these cars. Mine didn't make any noise when new, but now it does it all the time and lasts from 3-5 seconds.

.2PDK

Gotta love the mystery sounds/smells after shut down.

I keep telling my wife if I could bottle that "porsche smell" she'd be wearing it at all times.

I don't need to tell anyone what her reaction was...

Leicht

Just want to update that my local dealership said The farting or humming noise after shutting down the engine is apparently not normal.

Had to replace the actuator that’s causing the humming noise and costs less than USD200 I think.

Mine is base 2017 718 Boxster. Surprisingly my friend, who’s base 718 boxster was build earlier than mine, never heard of any humming or fart noise woth current mileage ~70,000km at the moment.