Hi all,


This in on a 2003 S40, 150k miles.


I have noticed a metallic rattle coming from the PS pump, alternator, a/c compressor area. It sounds just like the rattle from shaking up a can of spray paint. I used a long piece of vacuum hose as a stethoscope and it is almost definitely coming from the alternator. I'm guessing a bearing is going out, but I have never had an alternator do this so who knows.


I plan to pull the belt off and spin the alternator to see if I get a noise that way, check for play in the pulley.


has anyone replaced the alternator on a 2000-2004.5 S40? I watched some videos on youtube and they were pulling a lot of things off to get to it, including part of the upper radiator? The general issue was no room to pull the alternator out. But those were not on an S40. Just need to figure out the best approach (from above of below), and don't want to remove anything if I don't absolutely have to.


Thanks for reading

 

Does the rattle change if you add a load (such as the high beams,blower and rear defogger etc) to the alternator?

 

I'll check tonight or in the morning. I didn't think there was anything "mechanical" in an alternator related to load... anything you are suspecting in particular if the noise does or doesn't change?


Its a pretty $ part, and not the easiest to replace judging by what I've read... Either way before I pull it out I'm going to wrap a cable around the pulley and spin it up 'lawn mower' style to recreate the noise.


Now on top of this it has a really bad miss when cold. I've replaced the vacuum lines around the throttle body, they were dry rotted pretty bad... but it still misses when cold and I can feel a loss of power overall (could be drag from the bad alt?). This winter has been pretty rough on my poor old Volvo.

 

I think replacing the alternators on our earlier S40 is pretty rare, I have not heard of them going bad. Given this, you could probably find a used one easily at a fraction of the cost and odds are good it would last a long time.
If you wanted, you could find a rebuild shop for the unit you take out.

 

agree - most of the time when an alternator fail these days its the voltage regulator not the bushings or bearings - most shops just swap out the whole unit...

 

Nice weather today, 65°F and sunny so I got to look at the alt issue. Took the belt off and wrapped some string around the pulley and pulled to spin it up. Smooth and no knocking noise. I started the engine with the belt off and no knocking noise coming from the engine.

Also spun the a/c compressor, smooth too. The power steering I couldn't get the string on it, I just spun it by hand. Hard to tell without getting it up to speed. I'm thinking it must be the PS pump, there isn't anything else around that area.

I'll keep looking.

 

I suspect it may be either the AC clutch mechanism rattling (trying to engage or floating?) or the alternator decoupler pulley (PN 30782701). I haven't looked at how that's set up or how you'd test...

 

The belt tensioner?