Northstar Engines and System Technical Discussion Discussion, Witnessed some component fail, what to do? in Cadillac Engine Discussion; Something under the hood started making a rhythmic squealing sound, at a pace slightly less than two per second.
Something under the hood started making a rhythmic squealing sound, at a pace slightly less than two per second.
I was trying to locate the sound, which sounded like it was coming from one of three places -- serpentine belt, power steering pump, or passenger side of engine.
While I was listening, the squeal changed over to a "tink", "tink", "tink" sound at the same rhythm. And then all of a sudden, it sounded like something metal broke off and clanked around a little, during which time I jumped around the door as fast as I could and turned the engine off.
Can anything metal in the engine "snap off"? Perhaps a lifter or something related on a cam (I've always though I had a lifter noise, but never able to confirm). A timing chain maybe? (Are there two, and are they on the passenger side?)
Any suggestions of what to do now? I dubious about even turning the engine on.
All this happened when I returned home from some heavy driving, testing the car and A/C, which was ice cold since I just finished installing a new compressor over the weekend (using advice from this forum; professional vacuum test and refrigerant charge). I don't think the A/C was the culprit here because it was off when I was listening and it seemed to work great when on over the last day. Just thought I'd mention it in case though.
Hints on what to look for? Advice on how to try and diagnose? Toe to dealer?
Sounds like something with the serpentine belt - tensioner, idler pulley, or A/C compressor clutch assembly has fallen apart. You would probably not hear a squeak-squeak or tink-tink coming from inside the engine.
Check the water pump tensioner pulley too. I had one come apart on me on the highway at 80mph. Thought it was a headgasket when the temps started to climb. The bearing had seized and come apart....that could definitely make some noise. I would suggest removing the belt. The spin each pulley by hand. The alternator, tensioner, and idler pulleys (as well as the compressor pulley, if the clutch isn't siezed) should spin over nice and easier with just a little effort. If any of them are hard to turn, or don't turn, or wobble..then there's a problem. Start with that and let us know what you find.
OK I found the source of the problem: the plastic fan blades behind the alternator pulley shattered and got caught up in the serpentine belt, ruining the belt
I hope the damage is limited to the belt and the plastic alt fan. I hope the blades weren't partially destroyed for a while, perhaps contributing to a premature alt failure. I'll also check the other pulleys on the serpentine line for damage.