hissing noise coming from engine..what could it be?

[K321]

Dear all. i have checked the usually informative saab central website and found no answers.

My car when i start it up is making this hissing noise the sound i can describe it best as if a tyre is losing air- but its not the tyre, the noise is coming from the engine. When i take the key out, the hissing noise is the last noise I hear until the car dies. Last night, the noise was VERY loud, a quick prod of the throttle and the noise was subdued, the car runs otherwise excellently but I am just worried about this new noise i can hear.

ANy ideas what it could be? i have checked oil, coolant and fluids and everyting is fine. Noise seems to be coming from left hand side of the engine

[Prof Beard]

K321 said:

Dear all. i have checked the usually informative saab central website and found no answers.

My car when i start it up is making this hissing noise the sound i can describe it best as if a tyre is losing air- but its not the tyre, the noise is coming from the engine. When i take the key out, the hissing noise is the last noise I hear until the car dies. Last night, the noise was VERY loud, a quick prod of the throttle and the noise was subdued, the car runs otherwise excellently but I am just worried about this new noise i can hear.

ANy ideas what it could be? i have checked oil, coolant and fluids and everyting is fine. Noise seems to be coming from left hand side of the engine

Hissing noises are usually caused by air/gas escaping? Have you checked all hoses/tubes? Why not open the bonnet and stand next to lh side and get someone else to rev and turn it off?b

[cptsideways]

Idle control valve leak by the sounds of it!

[K321]

Prof Beard, i tried that, it does sound like gas escaping

what is idle control valve? how would i fix it? and the engine wont blow up would it?

[Prof Beard]

K321 said:

Prof Beard, i tried that, it does sound like gas escaping

what is idle control valve? how would i fix it? and the engine wont blow up would it?

It not easy to explain where it is but there is a good picture in the Haynes manual - it has a wiring connector going it and air tubes going in/out - it could there the air leak is...

Edited by Prof Beard on Thursday 20th September 22:08

[K321]

prof beard, well thanks for that, at least i now know what it is, i was so clueless i thought it was the head gasket

anyway, i will check the valves tomorrow etc, if i dont fix it now would it mess up the engine?
regards
K

[Prof Beard]

K321 said:

prof beard, well thanks for that, at least i now know what it is, i was so clueless i thought it was the head gasket

anyway, i will check the valves tomorrow etc, if i dont fix it now would it mess up the engine?
regards
K

I found this:

http://pages.infinit.net/mlbriand/saab/iac/page1.h...

It's actually about cleaning the IAC valve, but has good pictures of all hoses, locations etc

[tigran]

Could I ask what car it is?

[Prof Beard]

tigran said:

Could I ask what car it is?

I'm assuming it's the GM900 Cabrio in his profile...

[K321]

thanks a lot Prof

and tigran, yep its not the volvo..thank goodness..and still got the porsche - trying to sell the damn thing- its my one and only SAAB!