Help me find the noise

My Malibu is about to drive me crazy:screwy: . I have a noise under the hood and between four of us we can't figure out or agree on what or where the noise is coming from. One time it sounds like a vacuum line off and air sucking in then it sounds like a belt slipping. I have checked the belt tensioner, alternator, ps, water pump, and ac for bad bearings. The funny thing is is does it worst when the engine is under a load like when you are going up a hill or when you or really laying your foot to it in 2nd gear after it has changed out of first and you can hear a little better.

how many miles you have ? it could be the serpentine belt or the idler wheel / automatic tensioner. Noises are difficult to track down, they sound like they are coming from one place and may not. I use a very long tunnel or building to reflect the noise with all the windows down. I have also done stuff like taped a cheap microphone ( uses painters masking tape) hooked to a cassette recorder inside the car. Every new location I placed the microphone i would speak the location so i would know for sure when I listened to the tape back home. If the malibu idles ok, starts ok and accelerates ok , I would have to assume that it is not a vacuum leak or not caused by motor as long as it is not pinging you are hearing or knocking rapping. It could be something like a manifold exhaust leak or the trans. Is the trans to the correct level. ? could also be the drive axels.

It has 187K on it. The belt tensioner I don't think is it good and tight took off spun no noise. I hear a grinding in the alt through a broom handle but I get the same sound on the PS pump and water pump so I figure it is sound traveling the belt. The only thing I found different over the week end was the PS pump pulley moves in and out about 1/8 -1/4 in but is leaking no fluid and I stuck a magnet in the tank and saw no metal.

do you hear this in park or only while driving?

It is worst under a load and pulling a hill we have rode with our heads out the windows so much going to try the microphone idea tractorboy come up with.

that's a lot of miles , have you ever had your drive axels serviced, if not they either need it or might be causing the noise. although noise under load and lugging, my first thought is ignition ping ?

I am going to try that idea with the tape player got a new belt on it checked to make sure all the pulleys was tight and I put my finger in the wrong hole it's 127K.

I put my finger in the wrong hole it's 127K what ?

what ?
I hit the wrong key I hit the 8 instead of the 2 it has 127K on it. I found my problem it was the PS pump where the squeal was coming from and the deal with the up hill under a load making it sound worst I think was two bad plug wires. I checked them found they was not quite up to par so I got a new set put on a PS pump and belt cured that problem. I have had this car a while not done to much to it except change oil filters and such so when I saw the belt was a GM I guess it has never been changed. BTW who was the crack head at GM that came up with the way you have to put the belt on a side winder V-6. My goodness on my Blazer or pickup I carry a spare belt and wrench just for that sort of emergency but on my Malibu you have to prop the motor up take the front motor mount loose something you just could not do in 5 or 10 mins on the roadside like in most other cars and trucks.

Ummmm serpentine belts are not supposed to break like old v belts. I have never had one break. Always replaced them when they looked bad. I have to agree the motor mount deal is bad, then so what, hoe often do you replace the serpentine belt ?

I have never replaced this one. I bought this car at a sale and fixed front end damage on it this was a thief recovery. After I fixed it I drove it my youngest Daughter drove it we got to driving it here around the shop to town get something to eat next thing I knew I guess we adopted it and now after driving it and putting some miles on it getting parts going to get titles and things I having to start do some work on it beside regular service.
Answer to your question in relation to my other vehicles I keep a check on the belt for cracks but I change at 50K usually anyway.

...then it is not that big of a deal ?, undoing the motor mount if it only happens at 50 k. Do not go by the cracks on the ribbed side, new ones have just as many cracks as used. Maybe you could put Armor all all over a belt and wrap it in plastic , loop it over the motor mount for emergency. Then if the other one brakes , just take off the plastic.:naughty:

I had a serpentine belt disintegrate on a Lumina, with less than 60,000 miles on it. Not pretty. It sounded like pebbles bouncing off the hood when it happened. Little bits of rubber and cord got into the alternator, and it had to be replaced too.

After that, I replace my serpentine belts at least as often as the manufacturer suggests. I agree, the design of the Malibu, with an engine mount going through the area encircled by the belt, does seem a tad strange. I paid to have the belt replaced on mine, rather than go through that frustration.