TRouble with the 540

[Oxidefilm]

Here's the situation: Couple of months ago there was a heluva rattle. After much diagnosing it was coming from the alternator. I let it ride as I thought it was the ac compressor and didnt want to deal with it. ( had i known at the time it was the alternator, i would have replaced it.).

Flash forward. The rattle is gone and has been replaced by a steady vibration that i could initially eliminate by revving the engine. That no longer works and the AC doesn't work anymore. Also, the battery and parking brake lights on the warning panel come on all the time--sometimes dim sometimes full bright.

What should i do?

[Dagunster]

my experience has been, when a noise gets real loud, then dims, get ready for something to go flying out with explosive force.

You have to start digging or get it to a mechanic.

[Trasportador]

If your battery light is on, check the charging rate on your alternator, free at any area parts store I'm guessing. If bad(most likely the case) change the alternator, the car is starving for juice while it's running.

Not sure if the alternator's performance can affect the ac, but if the ac still does not work after changing the alternator, I'd get that system checked out, may have ran out of freon. If the AC clutch does not engage at all, then the system is most likely depressurized and will need to be checked for leaks.. Good luck with the repair..

[jfj707]

You can also just put a multimeter on the positive under hood connection and the other on the shock tower and measure the voltage output while car is running. Should be right around 14v. Or unlock the obc and run the battery voltage test inside the car. Ac problem is probably not related. I also say test the pressure and pressure switch, also check fuse 9, if compressor is not coming on. Also the compressor bearing can grenade and take out the clutch coil, rattling and causing extra load on the engine bc the bearing is no longer spinning smoothly - it is basically being dragged along.

[KyleCleveland]

Initial diagnosis says the alternator is failing and needs to be replaced before it seizes up and takes out a water pump or something else with it. Inspect your serpentine belt before you do the job, may as well replace it while you're there if you see any cracking.

An alternative and less likely theory is that you have an A/C leak which caused the compressor to seize up and your system is working very hard to keep everything spinning. This would probably be worse than described above.