Replacement interval for accessory and timing belt tensioner and pulleys?

Post by **abscate** » 05 Jul 2023, 04:11

Wizechatmgr showed me a great trick. Pack heavy grease around a “sealed pulley”, warm it with a torch and the grease flies in like magic

Post by **foggydogg** » 05 Jul 2023, 05:56

V50M66 wrote: 04 Jul 2023, 23:09 My serpentine belt tensioner was absolutely cooked at 170k. I'd do it. Not worth risking the engine over a hundred bucks or so.

Doing just the timing belt is a HORRIBLE idea. Do it once, do it right. If it's coming that far apart, why cheap out?

He mentioned above that he will change all the timing components, it is the accessory belt tensioner under discussion here.
I agree with Dr. Abscate on this matter, change the belt and leave the tensioner alone unless it feels wonky on inspection. My '00XC has its original serpentine pulley hardware on it at 325k.

Post by **FireFox31** » 05 Jul 2023, 11:38

Thanks for all of the advice. I will pull the belt, move the accessory tensioner to see how it feels, and spin its pulley to check for free movement. Should I expect the bearing to have a stiff drag to indicate health, while freely spinning indicates wear? The pulley is easily available for around $30.

V50M66 wrote: 04 Jul 2023, 23:09 If it's coming that far apart, why cheap out?

This is a great point. When doing timing, I will already have the coolant tank and more removed to give me access to the belt area, and be on the lift, set up, and ready to work. Do I want to do that preparation a second time to replace the accessory belt hardware when it fails? Proactive replacement can save that repeated use of time if the price is reasonable (which it's not with my double-priced tensioner).

It's easy enough to check the tensioner and its pulley so I'll do that. Might proactively replace the pulley as a compromise and inexpensive investment in not repeating the work.

Post by **erikv11** » 05 Jul 2023, 13:00

Freely spinning indicates the pulley is dry (no or minimal grease inside), doesn't tell you much by itself about bearing wear though if it's been run dry a long time the bearings are likely more worn. Healthy pulley has some drag yes.

454cid · Post by **454cid** » 05 Jul 2023, 13:09

No Volvo specific experience here, but on my truck I don't replace them by a schedule. I just check them by hand when the occasion arises. I had one that was short lived, and I've had one that went almost 300K miles. The short lived pulley started making noise as it ate the brass bushing up.... new one has a ball bearing. The ~300K mile pulley just had a notchy feel to it when spun by hand, no real slop.

The belt gets replaced when it starts getting cracked and I feel like doing it.... never had one break.

I do need to take an up close look at the belt on my S70.... my first time for a two sided belt. I did replace the serpentine belt on the 850 when I did the timing set, but kept the rest of the system.

If the serpentine belt fails, the nice thing is that you don't lose the water pump, like my truck would. The engine could safely continue to run until the battery gets too weak. Steering shouldn't be too bad while rolling.

Post by **Krons** » 05 Jul 2023, 20:57

Just did it on my kids 02 at 187k miles. Could bearing have went longer? Maybe but it felt rough and seemed silly to not change for $8.

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V50M66 · Post by **V50M66** » 05 Jul 2023, 22:03

454cid wrote: 05 Jul 2023, 13:09 No Volvo specific experience here, but on my truck I don't replace them by a schedule. I just check them by hand when the occasion arises. I had one that was short lived, and I've had one that went almost 300K miles. The short lived pulley started making noise as it ate the brass bushing up.... new one has a ball bearing. The ~300K mile pulley just had a notchy feel to it when spun by hand, no real slop.

The belt gets replaced when it starts getting cracked and I feel like doing it.... never had one break.

I do need to take an up close look at the belt on my S70.... my first time for a two sided belt. I did replace the serpentine belt on the 850 when I did the timing set, but kept the rest of the system.

If the serpentine belt fails, the nice thing is that you don't lose the water pump, like my truck would. The engine could safely continue to run until the battery gets too weak. Steering shouldn't be too bad while rolling.

Problem is, more often than not the serpentine belt will get sucked into the timing belt on these engines and grenade the entire motor. Which is why serpentine belt replacement is almost as important as timing belt replacement on these

Post by **FireFox31** » 05 Jul 2023, 22:24

V50M66 wrote: 05 Jul 2023, 22:03 Problem is, more often than not the serpentine belt will get sucked into the timing belt on these engines and grenade the entire motor. Which is why serpentine belt replacement is almost as important as timing belt replacement on these

That's a solid tip, thanks. I bought a new accessory belt tensioner pulley and will check the existing equipment to determine if I replace the whole tensioner or just the pulley. The belt will be replaced, of course.

Darn, $8 for a P2 tensioner pulley. The P80 INA one cost $30. Still cheaper than a ruined engine from belt failure.

V50M66 · Post by **V50M66** » 05 Jul 2023, 23:33

You’re already in there, and I’d much rather spend another hundred bucks on stuff that won’t even take much more time to put in if it means not potentially spending thousands for a new engine down the road

Post by **abscate** » 06 Jul 2023, 04:14

That’s a BMW thing, serp belt wiping out the timing belt. It doesn’t apply on the P80 and P2 platforms unless you are really unkarmic