Drive belt replacement - parts needed

ylwgto · Post by **ylwgto** » 28 Apr 2023, 16:01

Gonna do the drive belt on my '09 XC90 3.2 (140K). Will also replace the water pump and replace brake vacuum pump seals while I'm at it.

Here are the parts I believe I need:

Drive belt tensioner
Idler pulley
Alternator decoupler pulley and cap
Belt
Water pump with gasket
Water pump coupler
Brake vacuum pump re-seal kit

Am I missing anything? Does the Alternator decoupler hub wear out as well (the belt thing inside) or do I just need to replace the decoupler pulley?

Anything else that can be addressed while all that stuff is off?

chitownV · Post by **chitownV** » 29 Apr 2023, 01:13

All the 3.2 info you need here. Also read the detailed sections after the table. Post #7.
https://www.swedespeed.com/threads/the- ... st-7332383

ylwgto · Post by **ylwgto** » 29 Apr 2023, 12:11

A great thread, I've read it many times!

I specifically want to know if I should replace the Alternator decoupler hub and the belt thing inside (on the alternator side of the block bearing) or do I just need to replace the decoupler pulley (on the drive belt side)? And/or the decoupler pulley seal?

I've read the pulley can wear out and fail right around my mileage, but have not seen anything about the actual decoupler failing...just want to know if I should deal with it while everything is apart.

chitownV · Post by **chitownV** » 29 Apr 2023, 13:12

The alternator can be done completely independent of the serpentine work. Since the serpentine service is extensive, focus on that for now.

In addition to what you listed earlier for the serpentine,
- cooling thermostat (you might already see traces of seeping from the rubber gasket). Can be changed without removing the intake manifold.
- large radiator coolant hoses
- coolant small hose and o-ring for oil cooler
- Volvo coolant or G48 European coolant
- A/C side decoupler pulley (bolted onto engine & has ribs matching the belt), cap, seal, bolt, special tool. (why Volvo lists this decoupler under the alternator section in the parts list is a mystery to me). This decoupler drives the entire serpentine system and does go bad, usually ~120k-130k miles. Requires serpentine removed to gain access.
- Maybe need an A/C bracket alignment tool. Please read the 3.2 post as it describes how to avoid needing the tool, but be prepared in case you accidentally turn the alignment spacers. The A/C bracket is removed to gain access to the decoupler.

The separate alternator work requires you to remove the intake manifold (replace rubber gaskets). If you do that later, I would not just change the decoupler attached to the alternator; I would change the entire alternator as it comes with a new decoupler as well. Since the alternator bearing can wear out and the voltage regulator can go bad, changing the entire alternator is advised. (Why Volvo lists this decoupler bolted onto the alternator under the serpentine section in the parts lists is a mystery to me.) This decoupler is a cog design, or has teeth.

ylwgto · Post by **ylwgto** » 29 Apr 2023, 13:55

Got it, I understand now. I really appreciate the insight!

I've already done many of the other things you list as they have failed:

- cooling thermostat...mine had the broken tabs on the inside, terrible design
- large radiator coolant hoses...mine were swelling and ready to fail
- coolant small hose and o-ring for oil cooler...had a seepage leak here from cracked plastic insert, replaced this when I did the thermostat

is "A/C side decoupler pulley (bolted onto engine & has ribs matching the belt), cap, seal, bolt, special tool" the first item listed below:

https://www.partsgeek.com/ss/?i=1&ssq=x ... ler+Pulley

chitownV · Post by **chitownV** » 29 Apr 2023, 14:24

Ah, I see you already experienced the pre-Volvo recommended service interval (150k miles) parts failures, thus why all this work is suggested to do closer to 100k miles based on real-world owners’ feedback like yourself. People try to justify or argue against doing it earlier than 150k miles like it’s an opinion, but the real-world ownership experience is not an opinion, lol.

There’s a link to the correct decoupler pulley in the 3.2 post I shared earlier, under the decoupler section. But here you go.

I like INA bearings because it’s the quality factory brand used on all European engines. Look at this kit, but don’t buy the kit. You don’t need the metal seal install tool as the seal has a plastic tool/guide already (look at the pic). Get the individual parts, minus seal tool, and add the bolt. I used the bolt/pulley tool listed when I did mine.
https://www.fcpeuro.com/products/volvo- ... 31316803kt

ylwgto · Post by **ylwgto** » 29 Apr 2023, 14:48

Yes, all those things failed between 120-135K.

is this the bolt for the decoupler pulley?
https://www.fcpeuro.com/products/volvo- ... lvo-988566

Thanks!!

chitownV · Post by **chitownV** » 29 Apr 2023, 15:02

Just an FYI, you can cross reference (or double check) Volvo part numbers at any one of the Volvo dealership parts stores. Just do a Google search for Volvo parts. I am not a dealership parts store, lol.

ylwgto · Post by **ylwgto** » 29 Apr 2023, 15:47

I'm aware. Sometimes they list parts in VERY weird categories.

All the decoupling pulley bits are listed as transmission parts??
https://usparts.volvocars.com/a/Volvo_2 ... D352775D1A

Anyhow, I assembled all the Volvo part #s needed so I'll post here:

Engine decoupler pulley Bolt
Part Number: 988566
Engine decoupler pulley
Part Number: 31316803
Engine decoupler pulley cover
Part Number: 30777012
Engine decoupler Crankshaft Seal
Part Number: 30711317
Accessory Drive Belt Tensioner
Part Number: 31401286
Accessory Drive Belt Idler Pulley
Part Number: 31401193
Serpentine Belt
Part Number: 30757007
Water Pump Kit. Coolant Pump
Part Number: 31219000
Water Pump Coupling
Part Number: 31219096
Repair Kit. Vacuum Pump
Part Number: 31401556

Momackin4U · Post by **Momackin4U** » 23 May 2023, 05:45

Drive belt replacement