Strange hissing in my SL

[discoking]

Fired her up this morning to go to work and there is a strange hissing noise comming from the air vent to the right of the steering wheel.The hissing stops as I accelerate but as I ease of to cruise or back off completely then the hissing starts again.

Any ideas?

Oh it's a '92 300SL-24

 

[television]

You have a vacuum pipe off from the headlamp adjuster probably though it could be a heater control pipe

http://www.detali.ru/cat/oem_mb1.as...722.352722.500&GM=717.451&CT=F&Cat=515&SID=80

 

[discoking]

You have a vacuum pipe off from the headlamp adjuster probably though it could be a heater control pipe

http://www.detali.ru/cat/oem_mb1.as...722.352722.500&GM=717.451&CT=F&Cat=515&SID=80

Thankyou.

It looks like it is probably the headlamp adjuster pipe as when I move the headlight adjuster switch the hissing gets louder or quieter depending on position.

 

[television]

Thankyou.

It looks like it is probably the headlamp adjuster pipe as when I move the headlight adjuster switch the hissing gets louder or quieter depending on position.

If a pipe is off on the rear of the head lamps themselves, this can also give a hissing sound, on a good system though, you can hear the hissing from the headlamp switch when you turn it in one direction, but is should stop once you are not turning it

 

[discoking]

Strange cos after you posted I went to give it a quick check before my last reply and I've just gone out to the car now cos I got a a spare few mins and wanted to have a look-see and the hissing as stopped.Took her for a quick drive and no hissing at all even after playing with the adjuster.

Old cars a funny and I'll put this down to her having a little characteristic quirk