I've been using this forum ever since I got my Magna back in 2009 but this is my first post!

Everytime the AC compressor engages or disengages there is a short squeak which becomes louder and more prolonged with more revs.

The auto climate control seems to turn the AC compressor on or off very often, e.g. every 1 minute so the squeak happens quite often.

Anyway it has been doing it since late 2009 but I still have not figured out what is causing the noise. Any ideas?

How is belt tension - if its not correctly tensioned then it will squeak.

Go out to the car, and press on the belt that drives the AC compressor with your finger, if it moves (deflects) a lot and easily, time to adjust the tension.

While you are out there check the condition of the belt itself, is it hard and brittle and shiny? or still feels like a new one? Does it have any cracks? How old is the belt?

I find with my car - when the AC is on, the belt / compressor will occasionally squeak once when Im pushing the car hard (making it rev reasonably high in the range) - I will get a quick chirp and then the AC compressor is disengauged (I assume this is to protect the compressor from being spun up too high / too much stress)

Totally agree with doddski! A/C/power steering belt problem. The belt might need replace.

The belt does flex a little, probably about 0.5 - 1cm reasonably easily. I looks in okay condition though, possibly a tad brittle. Where is the tensioner?

The chirp you describe is exactly what I'm getting except at idle, and at higher RPMs it is a long screech.

Is it normal for it to engage and disengage so often? It doesn't seem like it would be a good idea engineering wise if this is normal.

Cheers.

Im not quite certain myself where the tension adjustment would be for the AC - Possibly on the compressor itself - loosen the bolts off and shift the AC slightly away from the crank then retighten.
I have not done this myself on a Magna (only on old ZL Fairlanes etc - and this is how its done on those) so please do not take my word for it on adjustment side of things.

If its brittle - replace it.
If its not able to grip the pulley on the AC - it will slip and chirp.

New belt from Mitsu is only $26 bucks anyway - and cheaper if you go to Autobarn / Supercheap I am sure..

Pesonally when I hear screaching / chirping from belts in a car, I first start with checking and replacing the belts and checking adjustments - They are cheap and relatively easy to do. (belts have to be replaced at some point anyway on cars)

Is the AC still cold? What temp are you setting it at?

On hot days - the ac/cc obv has to work harder to reach and maintain a set temp - so the CC will be cutting the compressor in more often.

Yeah the AC is still cold. I usually have it set between 20 and 25 but even if it is on its lowest setting on a hot day the AC still seems to cut in and out which is quite annoying. Just while I'm sitting at the lights it seems to alternate a few times.

Might try tensioning it first and then a new belt. It doesn't seem there is that much room to work so it would seem just changing the belt would be a chore?

Just looking at the ellery workshop manual it appears that there is an adjustment pulley with an adjustment bolt which can be turned clockwise or anticlockwise to achieve the desired tension.

I've just done this - replaced both belts. Checking adjustment, and making adjustment is an easy thing to do first, and its free.

When it comes to replacing them - the AC/Alt belt is ridiculously easy. Did it with one hand. But the power steering belt is tricky... you're going to need two hands at least, and a large vocabulary of swear words.

I replaced both belts and both idler pullies on mine - $97 for the lot. Shop around for the best prices, but dont stimp on quality either. AND, dont spend any cash until after you've determined the bets are shagged, or you're out of adjustment.

Belt numbers should be 4PK900 and 6PK1195. Though, I'm running a 6PK1220 from Gates on my AC/Alt.

Magna TL 2004
Hi guys, don't know if this was the best place to post but it's my first post so here goes.
My problem is that the alternator tension pulley / idler pulley has come free. It now sits against the car body and the end of the bolt that it should be on!!
Now it has been making a noise ever since it's last service. I checked the workshop manual and the mechanic would have needed to loosen the fixing nut to this pulley when adjusting the new belts. Is it possible that they never tightened the nut again, and if so should I be taking it back to them???
Keep up the great work guys, love the forum