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Discussion Starter #1
I have a 1994 sts that has started sounding like a mac truck. the noise is loud but not all the time, sounds like it's out of water or something but pump is not leaking, temp stays at normal range and no codes are popping! it is coming from engine not exhaust so something is wrong but haven't got a straight answer about what it could be. afraid to drive it much longer! please help!
 

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1997 Eldorado, 2003 Audi RS6
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Sort of a vacuum cleaner sound? Malfunctioning air injection pumps can do this on BMWs, never heard it on a Cadillac though... Usually the GM electric smog pumps just sieze up when they die, or they get water in them and it freezes and the motor burns out.
 

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Sedan de Ville, CTS
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Get or make a stethoscope. BE CAREFUL YOU DO NOT GET GOBBLED UP IN PULLEYS OR FAN BELT.

Good water pump will have almost no noise. Alternator will normally have a low vibration sound from (the equiv of) armature.

Test everything. (ps, smog, ac, tensioner, etc.)

You can use a broomstick for this. Again, be very careful.
 

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A good makeshift stethoscope is to use a piece of pliable heater hose, smaller if necessary, put one end in your ear, and use the other to point at things.
 

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Discussion Starter #5
het thanks for the info, have a stethascope, used to be in nursing so will try that if I can get to it! not a lotta room there. will get back to ya. any more idea's out there?
 

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White Diamond '03 DHS (with DTS floor shift)
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If you are using a medical stethoscope, remove the round pick up or whatever it is called and replace it with a length of copper tubing. I added a small rubber tip to mine and drilled a hole in it. That cuts down on noise when you touch it to anything.
 

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Sedan de Ville, CTS
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If you are using a medical stethoscope, remove the round pick up or whatever it is called and replace it with a length of copper tubing. I added a small rubber tip to mine and drilled a hole in it. That cuts down on noise when you touch it to anything.
Like my g/f used to say "Anything long will work."

I like the idea of the rubber (heater??) hose. I think a real stethoscope might get gobbled up in the fan belt or pulleys. Scarey. Broomstick or very heavy long screwdriver is also workable.
 

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White Diamond '03 DHS (with DTS floor shift)
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Many ways to skin this cat, but when I got hold of a medical stethoscope and made the conversion mentioned above, it was amazing what you can hear.
 

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Discussion Starter #9
new update, the noise is not coming from the pump on the drivers side. it's coming from the passenger side for sure near pulleys. all the pulleys look ok and belt is not worn at all. sounds like more from under them somewhere and almost but not quite like a vacuem leak! any thoughts?
 

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White Diamond '03 DHS (with DTS floor shift)
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Idler or tensioner pulley is most likely. Release the belt tension and spin them by hand. The culprit should show itself.
 

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Discussion Starter #11
Re: is it water pump noise or other? update.

:(me again, I was thinking tentioner or pulley too but I'm being told it's coming from power steering unit, it does make the normal noise you would here when steering unit is going but this noise is all the time, even when wheels are not moving or turning. could the pump make this noise too? and does any one know the best place to get a pump without breaking the bank!
 

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Discussion Starter #13
thanks for the info, still haven't figured it out but know it's not the water pump at least, noise is on opposite side from that, coming from passenger side near pulleys underneth them some where. are there any vacum lines under that area that would make noise? some one said it was my powersteering pump but the noise is under that area. not the normal whine you here from steering unit. gets louder if you take the car mor than a few miles. any idea's what it could be?
 

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White Diamond '03 DHS (with DTS floor shift)
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I think the vacuum reserve canister may be under the battery.
 
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