AC making a noise

[goldfinger]

Over the past couple weeks I've noticed a noise coming from my car that hadn't been there before. I don't know much about cars, but I want to say it almost sounds like an exhaust leak.

It ONLY happens after the car sits overnight and is started again the morning. I thought maybe it as piston slap or valvetrain noise. I've narrowed it down to it ONLY happening when it's started with the AC on. With the AC off there is no noise, the engine runs smooth and quiet.

As soon as it's warmed up a little, the noise goes away.

Any ideas? I've checked the belt and it's not loose or anything. What could possibly be the source of the noise?

It's a 97 Grand Am with the 2.4 DOHC.

Thanks

 

[outrun]

I know this 1st hand....correct me if I am wrong but your vehicle should be equipped with the V5 compressor.

There is a strong possibility theough a minute leak or failure of the A?CC canister drier pellets that water has infiltrated the system causing your valves to wear out and hence noise.

The prime culprit of this will be obnoxious high pressure line readings ~300 psi or so!!

Have it profesionally checked and our dye tested.

I just choked 700$ for a thorough A/C job....425 for the compressor itself...identical symptom at the beginning noisy compressor

 

[goldfinger]

Just for the record in case anyone else has a similar problem.....

I also noticed that it just didn't cool near as well as it used to. I took it to the shop and they checked it, put dye in it, and added 1/2 can of R134. The noise has went away completely and it blows much cooler.

I was even more amazed that they only charged me for 1/2 the can. Most places would charge you for the whole thing and use the rest in somsone else's car.

 

[Ugly3]

Never would have guessed that was the problem - thanks for the follow up info.