P2 Alternator pulley—thoughts on solid? Decoupler counterhold 30667878

[leapdragon]

Hi all,

I have a 2002 V70 XC with 170k miles on it. Recently had an alternator diode (presumably) go bad, leading to odd electronics behavior and no charging. Bought a new replacement alternator, installed it, went ok, car now running apparently pretty well for a few days, all voltages and behavior check out.

During install, I noticed a difference in the pulleys but didn't think too much about it. Then I started to google.

So, turns out I've installed an alternator with a solid pulley. The one that came out has a decoupler pulley on it. I was not previously aware of the difference. The decoupler on the old one is frozen solid, i.e. it's behaving like a solid pulley, old alternator rotor turns freely but the pulley and rotor are 100% bound together, no play between them in either direction.

I'm reading all kinds of scare stories about replacing a decoupler pulley alternator with a solid pulley alternator—it's going to destroy the bearings in the other units on your belt path, it's going to throw belts every 10 minutes, kill your tensioners at an alarming rate, harm your crankshaft, etc.

My question for the group: True? Does the solid pulley matter in a significant way? If I hadn't been running with an effectively solid pulley for who-knows-how-long (at 165k, alternator was original, and apparently decoupler pulleys are only expected to last 50-60k?) I'd be pulling this alternator and installing a decoupler pulley on it. But the car seems to be running fine, and I presume I've been driving with a seized pulley for at least tens of thousands of miles (daily driver).

Does any of this matter? I do tend to replace my serpentine belt about every 30-40k, though tensioner only once in the life of the car so far. Point being: should I break it all down, pull the alternator, and replace the solid alternator pulley with a decoupler pulley, or should I just forget about it and move on seeing as how the car seems to be running happily?

Opinions and rationales?

[93SCMax]

My OAP pulley seized @ 135k miles, not 50-60k. It shredded the serpentine belt but nothing else was damaged.

I'm of the opinion that Volvo designed the system specifically with the OAP pulley, so it's the only way to go. Why take a risk changing the design? I believe a new one was only $35-$40 4 years ago.

If you decide to install a new OAP pulley, you will need a specialty tool to install/tighten the new pulley. You may even be able install it with the alternator on the car.

[xHeart]

This may help a little https://youtu.be/U7MD85ogCEo

Our 2001 V70XC alternator is OAP design, more here viewtopic.php?f=9&t=92790

[pgill]

Is your tensioner moving excessively at idle?

Look at this video

Solid pulley

OAP

OAD

Full disclosure my Volvo 3.2 came with a OAD and I replaced it with a OAP.

I did this because the OAD was seized solid prior to the 150,000 mile maintenance interval.

In the video you can see that the Tensioner movement is reduced significantly by installing a OAP and that it is reduced a little more with the OAD (I ignore the comments from the people that made the video, who are trying to sell me on the OAD)




Good luck

Paul

[cn90]

The P80 cars (1993-1998 850, S70, V70 etc.) run on solid pulley for alternator.

[abscate]

The P80 cars (1993-1998 850, S70, V70 etc.) run on solid pulley for alternator.

...except the bastards.....1999-2000

[leapdragon]

Hi everyone,


Thanks for the input! I watched a few more videos on YouTube about OAP vs. OAD vs. solid today... And I did have an OAD pulley delivered and it's sitting here.

I went out and idled the car w/all the electrics I could think of running and then peered at the serpentine path for a while with a flashlight as it ran. Not a lot of vibration anywhere, including in the tensioner. Tensioner moves slightly every now and then, but nothing like in the videos, and there's really no belt shake/flap. I drive it every day so paid special attention driving today, no particular thoughts or impressions, no squeal, weird sounds, or weird motions on shifting.

I'm thinking I'll plan to get to it sometime over the next few weeks and install the OAD pulley on a weekend when I have a couple hours since I have an OAD sitting here, but won't rush as if it's life-or-death as the car doesn't particularly seem to mind.

Had another fiddle with the old alternator that came out due to not properly delivering current, and the OAD pulley is definitely frozen solid to the rotor, no play in either direction even with a fairly decent amount of force. No idea how long I've been driving like that. Last serpentine change was probably 20k miles ago but I honestly never check the alternator pulley (and didn't know to do so) so who knows.

[xHeart]

I'm thinking I'll plan to get to it sometime over the next few weeks and install the OAD pulley on a weekend when I have a couple hours since I have an OAD sitting here, but won't rush as if it's life-or-death as the car doesn't particularly seem to mind.

Impact tools are NOT recommended for pulley work.

[goldxc70]

My alternator pulley self destructed just before Christmas and shredded the serpentine belt in the process. I actually did mange to replace the pulley without removing the alternator. Before this happened, I never even knew about decoupling pulleys.

[abscate]

I'm thinking I'll plan to get to it sometime over the next few weeks and install the OAD pulley on a weekend when I have a couple hours since I have an OAD sitting here, but won't rush as if it's life-or-death as the car doesn't particularly seem to mind.

Impact tools are NOT recommended for pulley work.

Nice counter hold technique. XHeart!

Added part number and counter hold to title for search