Serpentine Belt Stopped Spinning - Bad Read Overrun Pulley?

FrickinHek · Post by **FrickinHek** » 20 Aug 2025, 09:11

Hey guys,
I changed by serpentine belt/READ overrun pulley and all other pulleys and water pump on my 2013 3.2 2 years ago. Today as my wife was driving she lost power steering, AC, and then after she parked the high engine temp warning came on as she was on the phone with me. I told her to turn it off immediately.
When I inspected it the engine sounds totally normal, no weird noises from the READ area. The serpentine belt is in great shape and has good tension. When the engine is on, the serpentine belt doesn't spin at all. On the left side of the READ unit the alternator coupler spins with the engine on. When the car is off, the serpentine belt will move freely both ways, not just one direction so I'm thinking the overrun pulley must have gone bad?
What is throwing me off is that the alternator isn't working either. The car needs a jump after being on for a bit. Shouldn't it be charging while the engine is running since the coupler is spinning? Or did the alternator coupler bolt possibly come loose as well causing it to stop charging?
Thanks!
Eric

Vova585 · Post by **Vova585** » 20 Aug 2025, 16:24

If the left side is spinning-great news. I would take anything, but failed READ unit. I would start with removing intake, removing alternator. Check if the bolt holding the drive gear for alternator is fully tightened. Possibly vibration from failing drive pulley caused it to loose? On the right side it is once again, either not fully torqued(requires special tool) drive pulley(which i doubt) or failed drive pulley itself(way more likely scenario.
You can check the voltage at alternator at this time and if low-verify if drive gear

is tight to READ. If normal- totally different issue and then check voltage at battery, inspect for voltage drop on neutral and positive cable(fuse link isln there is a weak spot)

FrickinHek · Post by **FrickinHek** » 20 Aug 2025, 21:41

Thanks for the response Vova. I've been meaning to clean the throttle body and MAF for awhile and guess there's no better time than now while I check out the alternator. When my wife first told me what was going on I was really worried it was the READ unit since I replaced pulley's and stuff not too long ago but I'm glad it's looking more like a failed pulley.

"either not fully torqued(requires special tool) drive pulley(which i doubt) or failed drive pulley itself(way more likely scenario."
I have the special tool and torqued it to spec when I replaced the pulley but who knows. Which drive pulley do you doubt failed? You mentioned a drive pulley that is unlikely to fail and likely to fail right after each other.

Thanks!
Eric

Vova585 · Post by **Vova585** » 20 Aug 2025, 22:04

Sorry for my word mess. I am busy during the day, but at times like to check here and then try to rush to write responce before I loose train of thought.
Left side- gear from the Read needs to be fully seated and torqued. I heard about several cases where that bolt got loose and was a reason for no charge(some people replaced alternator just to later discover that it was perfectly fine). I believe that that gear should not rotate without engine running if bolted properly. I think that overrun pulley is attaches to the alternator and both

connect through a rubber sleeve. Check if your overrun pulley still works as it should(not seized)
Right side-drive pulley that attaches to the read unit. In perfect world you should be able to rotate the belt in 1 direction only(while engine is off). If you able to rotate it in both directions-pulley is not bolted(which i was doubting especially now knowing you had special tool) or the pulley itself failed(which is likely the case, and hopefully is the case cuz everything else is very expensive).
Good luck.

FrickinHek · Post by **FrickinHek** » 21 Aug 2025, 20:26

Thanks again for the responses Vova. I'm going to start digging into this weekend so we will see. Hopefully it's just the right side drive pulley that is bad!

FrickinHek · Post by **FrickinHek** » 23 Aug 2025, 21:48

Alright have a new issue. I got my new belt side pulley from FCP and am trying to put it on but I can't torque it to spec. When torqueing it it'll keep going and going because the pulley on the alternator side spins with it. Is it possibly something wrong with the alternator side pulley/coupler or possibly a bigger issue? I just got the intake off but have to run and haven't gotten the alternator off yet.

Vova585 · Post by **Vova585** » 24 Aug 2025, 00:26

First question- was the pulley bad when you got to it?
Second- are you trying to torque it to 60NM?
Lastly: man, I am really sorry for your struggles. I hate ford/volvo and their bastard step child read unit. I never did anything like this so will not pretend to be an expert. Following logic it should be a single shaft that connects front and rear ends of the unit(drive pulley and alternator end). I would make sure your torque spec is correct. Next I would remove the alternator and try to apply counter force at the bolt securing drive gear coming out of the unit. This way you will minimize chance of creating damage to the gear teeth inside of the unit(cam drive, axillary drive) and maximize your success rate. If my understanding of the unit is correct(not an expert, so consider anecdotal evidence) those gears are being pressed onto the shaft. So it is possible(just my assumption) that while you are trying to torque the drive pulley the force is too strong which causes those gears to "slide" .
Really wishing you success in this. Please keep us posted and share knowledge

FrickinHek · Post by **FrickinHek** » 24 Aug 2025, 11:16

The first pulley was definitely bad. The new one I just got seems fine. It only spins in one direction.
I used two different torque wrenches, both set to 80nm which is what was recommended in FCP Euro's video. The pulley starts spinning at about 45-50nm. I'll try counter force from the bolt on the other side.
Thanks again for your responses Vova. I appreciate your help!

Vova585 · Post by **Vova585** » 24 Aug 2025, 13:26

I dont have exact volvo torque spec for that bolt. FcP was wrong before on their recommendation(for example ac compressor for my 01 was listed as only to be used with 1234f refrigirant. After my independed research I found that mistake and fcp agreed it was wrong). My search came at 60NM for that bolt from independent rebuilder shop of read units
How the Volvo Rear End Auxiliary Drive (READ) Works and How to Maintain It - Automotive Tech Info https://share.google/P8xkwTgKTT0ldC0rN

FrickinHek · Post by **FrickinHek** » 24 Aug 2025, 15:52

Sounds good. I'll switch it to 60nm. Thanks!