whirring sound from behind dash
01-09-2018, 10:41 AM
#1
Rennlist Member
Thread Starter
Join Date: Jan 2018
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
whirring sound from behind dash
1992 928 GTS Auto -Developed intermittent mid pitch whirring sound from behind dash.
Increases with engine revs, decreases when AC turned on ( ? just lowering engine revs ) AC working normally noise not related to AC fan
Any ideas ?
Mike
Perth West Australia
Increases with engine revs, decreases when AC turned on ( ? just lowering engine revs ) AC working normally noise not related to AC fan
Any ideas ?
Mike
Perth West Australia
01-09-2018, 11:31 AM
#2
Rennlist Member
Couple of things come to mind:
1st " Increases with engine revs, decreases when AC turned on ..".
One of the vacuum pods has a hole in it, depending on the size of the hole will determine the pitch of the noise.
2nd " whirring sound from behind dash...".
What side of the dash, this could ne the Inside Temp sensor fan motor.
3rd " mixing motor,
Behind the Pod and lower than the Ignition Key.
My first check would be to see it the system still holds vacuum with the Key on and a Vacuum tester, test can be done at the Firewall next to the brake booster.
Welcome to the Shark Tank
Dave K
1st " Increases with engine revs, decreases when AC turned on ..".
One of the vacuum pods has a hole in it, depending on the size of the hole will determine the pitch of the noise.
2nd " whirring sound from behind dash...".
What side of the dash, this could ne the Inside Temp sensor fan motor.
3rd " mixing motor,
Behind the Pod and lower than the Ignition Key.
My first check would be to see it the system still holds vacuum with the Key on and a Vacuum tester, test can be done at the Firewall next to the brake booster.
Welcome to the Shark Tank
Dave K
01-22-2018, 12:40 PM
#3
Rennlist Member
Thread Starter
Join Date: Jan 2018
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for your reply Dave,
Sorry I haven't replied earlier, I've been unwell for the past week or so.
Sound seems to be coming from the central dash behind the air vents.
Very intermittent, sometimes there constantly, other times fades after a minute or two, I guess that does sound like a fan noise.
Not particularly mechanical myself but have a friend who has some gear, will try a vacuum test.
Many thanks for you help
Mike
Sorry I haven't replied earlier, I've been unwell for the past week or so.
Sound seems to be coming from the central dash behind the air vents.
Very intermittent, sometimes there constantly, other times fades after a minute or two, I guess that does sound like a fan noise.
Not particularly mechanical myself but have a friend who has some gear, will try a vacuum test.
Many thanks for you help
Mike