Humming Noise - C900 Saloon

Hi All,

there's a funny electrical "humming" or "whining" noise coming from the under the bonnet of the Saloon. Further investigation shows it to be coming from a largeish cylindrical object, which has vac hoses going to it. This object is situated in the drivers side inner wing, just below the power steering resevoir. The humming stops if I take one of the vac hoses off, or turn the engine off (obviously!) It's not apparent at idle..

So.. my question is..

what is this thing? why is it making a noise? how can I stop it?

Thanks!

Mike

Reply to
Mike P
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Hi, Mike. I assume on your car the driver's side is the right of the car as it's facing forwards, right? But, the PS reservoir on my '88 900 was on the left side, so I bet you'll get better answers if you say which side of the car and what year c900.

Reply to
Dave Hinz

Hi Dave,

Indeed... it's a 1984 C900 Saloon, 16 Valve Turbo. Right hand drive, so yes, the drivers side is on the right as you are facing forwards. The object in question is a white (light grey?) cylinder, about 3" in diameter and 7" long. It is attached at an angle and has some vac hoses coming out of it. When I pinch the vac hose, the noise stops. Leaking vac resevoir?

BTW, I found the hissing noise from behind the dash, and put the heater control rod back on - thanks to you and Grunnf :-) The spidery thing with all the hoses attached that fixes to the rear of the vent controls was completey detached...

Cheers Mike

Reply to
Mike P

"Mike P" skrev i en meddelelse news: snipped-for-privacy@uni-berlin.de...

It's a vac resevoir, which help holding vac, for temp-controls a.s.o. Reg. the noise, it's either a cracked hose or the cylinder itself has a crack.

Cheers!

Reply to
Henrik B.

Damn:-( I'll have to find a s/h one then I suppose.. what else apart from the heater controls does it operate? Any effect on the APC operation?

Cheers Mike

Reply to
Mike P

In article , snipped-for-privacy@privacy.net spouted forth into alt.autos.saab...

Mike. I replaced mine. the original one quacked. So I took apart and re-tensioned the spring, and it quacked worse, so I swapped the hoses and it still quacked, so i swapped the bottle for a second hand one, and it still quacks. Seems some cars do, and some don't. It connects to the underside of the interior blower filter housing, on a very small nipple that you might find tricky to see unless you really look for it.

Reply to
MeatballTurbo

Will this resevoir being knackered lead to my heater controls not working? They only blow on max setting (the 8 0'clock setting). None of the vents move.. I've put the pipework back on the distribution valve as it had been disturbed. The hissing from in the dash has gone. Also got the heater control rod on and can regulate heat. Can't get it to go where I like though.

Cheers Mike

Reply to
Mike P

Solved all the problems in one go - I'd not pushed the vac hose attachment onto the back of the air distribution control properly. A good shove, put the metal clip on and no more strange noises, and *most* of the heater vents work. Whatever I do though, air always comes out the side vents - what's wrong?

Thanks Mike

Reply to
Mike P

In article , snipped-for-privacy@privacy.net spouted forth into alt.autos.saab...

Don't know whether it should, but mine always does that too.

What have you found is the easiest way to get to the back of the ditribution switch? never figured that out yet.

Reply to
MeatballTurbo

I took out the very long screw that goes fromin from the bottom of the dash on the passenger side, made sure the radio cage was out and I found I could bend the dash enough without damaging it to at the rear of the distribution switch enough to put the plastic thing with all the pipes back on, and push the metal "clip" on to hold it on.

Just sorted the washers and cleaned it twice inside today. It's now almost habitable. MOT time on Tuesday, it'll fail on a rear tyre and the handbrake, but I'm not sorting those until I know what else is wrong with it :-) Looking through the old MOTs, it's been averaging around 20K miles per year for the last 3 years, so there can't be that much wrong I hope.

MIke

Reply to
Mike P

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