hissing sound

[amolak]

Hi,
After a few minute intervals, I keep hearing a hissing sound, like somebody is sucking air through a straw. It seems to be coming frm the air ducts. Is this the air con?
Is it normal?

thanks

Amo
S280 1998

 

[Koolvin]

sounds like a vacum pipe has come loose somewhere, lift the hood and see if you can hear anything there.....

 

[Alps]

air con

 

[Brian WH]

Originally posted by amolak
Hi,
After a few minute intervals, I keep hearing a hissing sound, like somebody is sucking air through a straw.
Amo
S280 1998

It's the Girlfriend/Wife taking a breath at the sheer power of the Acceleration.

 

[clegsr]

Or it could be the headlamp self-levelling control - this works via a vacuum as well - try adjusting it to see if the sound changes. - Has anyone been changing the headlamps etc?

 

[amolak]

Another guy has said:

its the AC compressor cycling - perfectly normal when the AC is running

is this true?

Amo

 

[Brian WH]

Originally posted by amolak
Another guy has said:
its the AC compressor cycling - perfectly normal when the AC is running
is this true?
Amo

Have you tried switching off the AC when the noise is present?
Or turning down the blower speed to eliminate, or otherwise the AC from the equation?