Random squeal and vibrations
 

Hi everyone,

few days back something strange started happening with my 2002 V70 - something that could be described as "oscillating vibrations". Couldn´t really determine the source, but it feels like it´s coming from the engine bay. This noise/vibrations seem to be constant, regardless of the rpm.

Little later – perhaps a day or two – an awful squeal occured. I´m pretty sure it sounds like a belt squeal. This, however, is not constant, it comes and goes. For instance on my 15 min drive from work I started without a squeal, halfway through the noise started, and when I got home it was gone again. I haven´t been able to determine any pattern for when it occurs and when it disappears. Except that WHEN it´s happening, it squeals above 1500 rpms.

Additionally, the check engine light came on at that time as well. I have a basic OBDII code reader, but when I plug it in it doesn´t find any error codes (I´ve used it in the past without any issues, so I know it works).

I replaced the serpentine belt and the tensioner pulley about 2k miles back, the timing belt was done about 35k miles back.

I´d be happy about any ideas or input about those issues.

Thanks in advance.

little change to the previous post - the oscillating vibration noise goes up in both frequency and volume with the rpms. It is always present, unlike the squealing noise which comes and goes randomly.
It really doesn´t sound healthy.

Update nr.2

I looked under the hood yesterday, took the timing belt cover off and listened to everything that was going on there for a bit. It sounded like the vibrations are coming from the alternator, the squealing from the timing belt / camshaft pulley. Took off the serpentine belt off, started it, and voila, both noises were gone. Which was kinda surprising, since I could have sworn the squealing comes from the timing belt. I swapped out the serpentine belt tensioner pulley some 2k miles back, so I was pretty sure it was alright. Checked all the other pulleys and the alternator one had a pretty good wobble and was loose to turn in both directions (which it shouldn´t as far as I know).
Little later my buddy came by with a professional OBD reader and pulled the code that my reader didn´t display - something about camshaft synchronization being off. Another surprise - I always assumed that if the camshaft was off, you would feel knocking or shaking or simply could tell that the car isn´t running as it should.
Anyways, I´m gonna try pull an alternator from a scrap yard (or buy a new one if nothing is available) before the weekend, switch them out and see if it made a difference. Fingers crossed it will.

I´ll post an update when it´s done, whether it was really the alternator pulley going bad.

last update to this thread

yep... it was the alternator pulley. Found out the hard way, on the highway. Ironically enough I was going to a garage to replace it. Long story short - the bearing of the pulley disintegrated, damaging the knob on the alternator, flying off and melting into the plastic cover between the engine and the right front wheel.
What really threw me off in the first place was the intensity of those vibrations. Never would have guessed a failing bearing on the alternator can make this much noise.
also, I did something between 200 - 250 miles between when it started and when it broke. So if you should encounter problem, make sure you start fixing it rather quickly.

https://cimg1.ibsrv.net/gimg/volvofo...5194566865.jpg
grinded alternator pulley knob
https://cimg2.ibsrv.net/gimg/volvofo...5a089000dd.jpg
https://cimg4.ibsrv.net/gimg/volvofo...47aa4a3a3b.jpg

How many miles were on your '02's alternator when its freewheel pulley died?

When my '02's regulator went out at 185K I gladly had the entire thing rebuilt at a local alternator/starter shop.

New bearings, pulley and regulator. Hope you got a good quality replacement.

161k miles on that thing..

yep I´ll see to have it rebuilt as well. But as I needed it back on the road quick, I went with a new Bosch alternator