A "What the Heck" Noise Fix
So I just fixed one noise on my '93 T/A (fuel pump) when another one pops up. This one is a grinding/squealing type bearing noise from under the hood, and it is somewhat annoyingly intermittent. Between three of us car guys, we can't figure out if it's the alternator, the power steering pump, or the A/C Compressor pulley bearing (with the A/C on or off the noise is the same). We use the long screwdriver method to listen...a long wooden dowel...and a mechanics stethoscope. One guy thinks it's the alternator for sure...then changes his mind that it's the power steering because the noise changes sometimes when you crank the wheel...the next guy is certain it's the power steering...but it might be the A/C pulley...and I'm sure it's the A/C pulley, except that it might be the alternator. So off comes the drive belt. The alternator spins freely with no rough spots or wiggle. The power steering pump spins freely with no rough spots or looseness...but the A/C pulley (which we know is not engaged) will not turn freely on one revolution, but will turn okay on the next revolution...something not right here. I didn't want to break the system apart if possible, so I got the right tools and removed the A/C clutch face plate and the pulley without removing the compressor (kind of tight, but do-able). With the pulley off, it was clear that the bearing was partially frozen and the seal was melted on one side. So off to the local parts store, where I am amazed that they actually have a part in stock that I need...and the bearing is made in "Japan"...and not China! Wow...I feel like I just won the lottery. I come home and press out the old pulley bearing, and press in the new one. It spins perfectly until I start to put it back onto the compressor. When is is about an 1/8 " on, the pulley will not turn. So I wiggle it off...see that it spins in my hand, and then ever so carefully begin to push it back onto the compressor. When it's barely on, the damn thing won't spin anymore...what the heck!...I do this on & off crap several more times with the same result...by now I'm getting real uncomfortable under this freakin' car...and it's dark now, so that everything I drop rolls into the darkest corner of my entire property which wastes more time...so I go to my bench and mic the new bearing. It is .004 smaller on the ID then the old one. Just to be sure I press the old bearing back into the pulley, and push it back onto the compressor. It spins like it did before (still worn out, but it does turn). So back to the parts store...they tell me a 3 day wait for another bearing (who knows if the POS will even work, anyway)...a 3 day wait for a $90 clutch/pulley assembly...or $180 for an in- stock new compressor with clutch/pulley. This is my daughter's car and she needs it for work the next day...so I come home with the new compressor...put everything together, evacuate & charge the system...start up the car, and wall-la...cold air!...and no bad noises...everything's great for about 30 seconds...and then suddenly, without warning...comes the original, sunuvabitchn bearing noise! I can't find a stick of dynamite close by...and I'm too tired to lift my biggest sledge hammer...so I calmly diagnose the noise as the alternator, for sure, and I haul ass back to the parts store before they close...I buy an alternator...and a power steering pump (just in case)...I put on the alternator, and the noise is gone...I stand there for a few moments holding the power steering pump up for the car to see as a challenge...the noise remains gone, and I can finish off my six pack before I go to bed to a happy ending. What spooks me most on this fiasco is that if I had just replaced the alternator in the first place, and not hand-spun the A/C pulley, the noise would have been gone, but the A/C pulley would have soon crapped out and left my kid stranded on some highway...moral of the story?