alternator pulley Topic is solved

[tahoetripper]

Noticed a clatter or clacking sound coming from around alternator when starting, getting louder in reverse gear and then subsiding when driven. A mechanic advised the noise was from the alternator "clutch" and that a new alternator would fix the problem. I've noted no issues thus far with battery or charging or any other performance problem.

So, two part question. 1) Should I try to replace just the alternator pulley or replace the alternator unit as suggested? 2) Online searches of parts suppliers show alternators for the 2002 S60 AWD in 120A, 140A, and 160A. How do I find the proper amperage of the alternator prior to removing it? Point is, I would like to order the replacement prior to removing the existing alternator as it may take as much as a week to get the new one delivered.

[oragex]

I've never heard before of an alternator to clatter. When the engine is idling, does the tensioner shake ? You can remove the serpentine belt and have the engine run at idle for 30 seconds see if the sound goes away. Also with the belt off you can check the pulleys: tensioner for play, a/c compressor for roughness and the alternator one (Youtube shows how to test it).

[vtl]

At this age it makes sense to replace alternator. However, most of cheap alternators (up to half of original price) are built with cheapest parts available. It makes sense to spend same or less money on rebuilding your own with good bearings, OEM pulley and voltage regulator, etc.

[jimmy57]

The one way clutch on alternators equipped with it can fail and make noises. If you remove belt and grab alternator pulley and sharply move it in both directions you should feel effort in one direction and it will slip in the other direction.
Most Bosch alternators have pulleys made by INA and you can find those sold online by several suppliers.
If you get a mirror and look at the black plastic back cover, I think towards bottom as fitted on engine, you can find current rating. It will usually be shown like "70->120A" where the low number is the approx output idling and 120 is maximum output rating at higher speed.

[93SCMax]

My recommendation would be to just replace the alternator pulley.

I had a failure last September, and after all the research and determining the cost of an alternator replacement, I opted to just do the pulley.

You can get the pulley from FCPEuro. For a 2001 V70 T5, it was $35.99 (PN 30667878)
You will need a special tool to remove the pulley...Metalnerd.com had it for $29.00 (PN MN3400).

I could not get the pulley off with the alternator on the engine, so I had to remove the alternator...not too bad if you have standard tools and patience.

I'd also recommend changing out your multi-belt at the same time for peace of mind. FCPEuro also has those.

A new alternator can be pretty pricey. Mine is a Bosch and has given me no issues so I stayed with it and just did the pulley. Interesting that when I was doing the research, the pulley manufacturers recommend the pulley be replace every time you change the serpentine belt. Volvo doesn't offer that opinion.

Good luck!

So, two part question. 1) Should I try to replace just the alternator pulley or replace the alternator unit as suggested?

[tahoetripper]

I'm going to give the pulley replacement a shot. Worst case, I end up pulling the alternator twice. Thanks for the responses and info.

[93SCMax]

You may get lucky and be able to remove and install the pulley while the alternator is still on the engine. I tried but couldn't remove the pulley since it was seized on the shaft. I needed to remove the alternator to get leverage to do the pulley install properly. Hopefully, you will have more luck than I. If you have the specialty tool, the pulley is much easier to remove. Good luck.

[cn90]

- My 2007 V70 with 104K runs fine, zero issues, but I am wondering...

- Does anyone know the lifespan of alternator decoupler pulley?

- How do you diagnose a bad alternator decoupler pulley?

[abscate]

Very few failures noted here but they are P2 items starting with the 1999 model year I believe

I wouldn’t recommend replacing with the serpentine belt since Volvo doesn’t. I have the tool if anyone wants Tom borrow vs buy but it’s close To shipping costs.

About all you can do to test it is take of the SERP belt and try turning the alternator in both directions and feel mechanical trauma

[93SCMax]

- My 2007 V70 with 104K runs fine, zero issues, but I am wondering...

- Does anyone know the lifespan of alternator decoupler pulley?

- How do you diagnose a bad alternator decoupler pulley?

I don't know what the design lifespan of the decoupler pulley is, but mine failed (seized) at 139k after 15 years of use. As I mentioned in my previous post, my research showed the pulley manufacturers recommending replacement every time the multi-belt was replaced. I think that's too often, but it certainly would be a preventative maintenance move...much cheaper than replacing the alternator.

To diagnose a bad decoupler, follow the advice give by abscate. When mine was starting to fail, it would make a noise when I started it up...usually only at idle. If I reved it, I couldn't hear it. I originally thought it was my power steering pump since it sits above the alternator. Eventually the noise got worst, the pulley seized, and I lost the multi-belt and all electricity.

My advice, to be proactive, replace the pulley when you put on your next multi-belt (assuming it's in the next few years). Waiting for it to fail would be a mistake. I imagine waiting until failure is what most folks do, and then they just change out the alternator.

By the way, my alternator and replacement pulley are running just fine two years later. Good luck.