Topic: Help! Hvac compressor turns on and off and makes noise Update!

[Ironhide]

Yesterday we had temperatures in the upper 90's.

So I thought it would be a good idea to turn on the a/c.

When I started the motor everything was fine, then I accelerated and heard a loud howling noise from the compressor (the noise appears every time when I'm accelerating).

The compressor turned off several times with a "klack" and it didn't matter if I was accelerating or driving a constant speed.

Only when I stopped the compressor didn't turn off and I had cold air the whole time.

Anyone with the same problem?

[DeepBlueGXP]

The compressor turns off during hard accelerations.  There was a TSB for howling noise though.

[Ironhide]

The compressor turns off during hard accelerations.  There was a TSB for howling noise though.

OK thank you. 

But I've an update about the a/c.

My GM dealer checked and replaced the coolant.

When he started the motor and the a/c, it began immediately to turn on and off .

He thinks it might be the pressure switch or whatever that is called.

Oh forgot something.

When the motor is cold the a/c runs without any problem (low air temperature / cold motor).

[Gentleman Jack]

Compressor cycling is a sign of low system pressure.
Try topping off the AC with a can from the auto parts store. Get one with the oil and sealant in it. You may have a tiny leak.
FOLLOW THE INSTRUCTIONS when adding the refrigerant.

[Critterman]

If you don't use the ac regularly (at least once a month) the seals can dry out and leak. 

[Ironhide]

Little update!

The refrigerant has been replaced and the a/c has been checked for leaks.

The good news: no leaks and the compressor seems to be in a good condition.

The GM dealer tried to figure out what's going on with the a/c, but at temperatures in the upper 70's everthing is fine and the a/c is working properly.

The problem starts at temperatures in the upper 90's.

First the GM dealer wanted to replace a pressure switch / sensor, but he isn't sure if this will solve the problem.

He noticed that my first Opel dealer removed the 2008 refrigerant charge label and replaced it with a 2007 version.

[Ironhide]

Finally figured out what's wrong with the a/c.

Opel replaced the 2008 label with a 2006 / 2007 one when they replaced the wheel housing.
Last year I had a service for the a/c and the mechanic replaced the refrigerant, but he charged the a/c with 0,74 kg (26 oz / wrong label)) instead of 0,47 kg (16 oz).
So when we had nice weather with temperatures in the upper 90's  the a/c pressure got too high and the compressor turned off to prevent damage.

Today the GM dealer charged the a/c with 0,47 kg and the compressor is running without any disturbing noise and the a/c is working perfectly.

[DeepBlueGXP]

Cool, glad you figured out the dealer screwed up.  Hope they didn't charge you for the troubleshooting and repairs

[Gentleman Jack]

GJ is right once again!!!!

[Ironhide]

Thank you guys for your help!

By the way I had to pay nothing for the repair, thank god!

[Sly Bob]

Compressor cycling is a sign of low system pressure.
Try topping off the AC with a can from the auto parts store. Get one with the oil and sealant in it. You may have a tiny leak.
FOLLOW THE INSTRUCTIONS when adding the refrigerant.

Glad that Ironhide got this sorted out. AC refrigerant might not be available in Germany, it's not available here but the READ THE INSTRUCTIONS on your post made me laugh.

Years ago when you COULD  buy refrigerant here, I bought a can to charge a not so old at the time 1982 Pontiac Phoenix that I owned. Glanced at the instructions without reading them completely and proceeded to connect and fill the system. After a short period of time with the valve open and the engine running, the belt on the compressor started to slip pretty bad, I had seized the compressor.

What did I do? I cut the belt as I couldn't afford at the time to have someone look at it and I told my wife we'd have to roll down the windows.

Ah, memories...   

[Sol Asylum]

GJ is right once again!!!!

Um no actually he had too much freon, you suggested he add more.

[Gentleman Jack]

Um no actually he had too much freon, you suggested he add more.

Shut uppa you face