98 V70 Serpentine belt tensioner question

[cn90]

Hummm,

Serp belt, when broken, will:
- cut the PS assist
- cut the alternator
- no AC

It is the alternator that will strand you.
So yes, serp belt maintenance is important.
Pulleys are pulleys, they rely on bearings to run, most bearings are due for replacement at 150K or so.
If one is short on budget, one can argue gently lifting the seal and inject some grease inside the bearing.

[98v70dad]

Thanks for the comments folks. The OEM Serp belt tensioner at the volvo dealer with new pulley installed on it is $68. The pulley alone is $34.00. To me its worth the extra $30 +/-. I appreciate the fact that the consensus here is that the tensioner seldom fails and would agree with that based on the little bit of research I did. I went to lunch with one of my gear head friends and asked him if he ever had a serpentine belt tensioner fail and his response was an emphatic YES and it was an inconvenient PAIN to deal with! He runs an older BMW which is a very well made machine like the volvo. Of course its a different car and a different part entirely but ..... I also asked the Volvo parts guy where I shop and I really respect his opinion (in six years he has never given me bad advice or pushed to sell me parts). He said "You'll probably be OK with out it and they are not a common failure item". He also said has seen plenty of failed ones over the years. His last comment was "they do fail"

[jcdillin]

Every time I have my serp belt off I give the 2 idler pullies a spin, if they spin for a long time or sound crunchy at all they get replaced. I just grab tensioner units from the pick and pull since they only charge $10 for the whole unit and it's easy to tell if the pulley is going bad.

Also when you change your belt if the old belt is halfway decent it's not a bad idea to throw it in with the spare tire, nice to have in the event you snap a belt in the middle of nowhere.

[rspi]

Is the "serpentine belt tensioner" also referred to as the "idle tensioner"? I've heard both used, now I'm wondering if they're synonymous.

No, the timing belt has 2 rollers, the tensioner roller and the idler roller.

[erikv11]

Be sure to replace the windshield. They do fail. Also the rear coil springs.

I'm just kidding! Some preventive maintenance can go a long way.

[cn90]

...No, the timing belt has 2 rollers, the tensioner roller and the idler roller.

Yes and no.

Belt is belt, whether it is TB or SB.

For the TB setup: tensioner pulley and idler pulley. The tension is achieved by the hydraulic tensioner.

For the SB setup: also has tensioner pulley and idler pulley. The tension is achieved by the mechanical tensioner.

So similar idea, slightly different setup.
As mentioned, most bearings go dry at 90K, then free-wheel at 150K or so.

[98v70dad]

I took care of a fleet of about 250 vehicles (airplanes) at one time for many years. Most parts that have typical failures fail around the same age or number of uses. Some go much longer. Some fail much sooner. You weigh whether or not to replace something early against the consequences of a failure. In my case being without a car even one day is something I can't live with. There is literally NOBODY close by to hitch a ride to work with. I have to take a days vacation if I'm without a ride and then spend it getting the car back on the road. $30 bucks for an extra part I may not need doesn't really phase me. That said the new part could fail in three days just like a windshield.

[benpineapple]

I took care of a fleet of about 250 vehicles (airplanes) at one time for many years. Most parts that have typical failures fail around the same age or number of uses. Some go much longer. Some fail much sooner. You weigh whether or not to replace something early against the consequences of a failure. In my case being without a car even one day is something I can't live with. There is literally NOBODY close by to hitch a ride to work with. I have to take a days vacation if I'm without a ride and then spend it getting the car back on the road. $30 bucks for an extra part I may not need doesn't really phase me. That said the new part could fail in three days just like a windshield.

5+ TRUTH

Especially considering the nature of high-stress parts to fail with little to no warning.

[rspi]

...No, the timing belt has 2 rollers, the tensioner roller and the idler roller.

Yes and no.

Belt is belt, whether it is TB or SB.

For the TB setup: tensioner pulley and idler pulley. The tension is achieved by the hydraulic tensioner.

For the SB setup: also has tensioner pulley and idler pulley. The tension is achieved by the mechanical tensioner.

So similar idea, slightly different setup.
As mentioned, most bearings go dry at 90K, then free-wheel at 150K or so.

HUH? Try to answer his question not my reply.

[dosbricks]

Tip: Do not buy INA tensioner assembly which is supposedly OEM. Example below:
https://www.fcpeuro.com/products/volvo- ... m-1275380s

Ten months old and it's chafing the belt ribs because the bearing in the roller has play (rocks back and forth) and so it does not track straight. Notice there is one review from April (I purchased the previous January)--one star--and returned for the same reason. I will be returning this one which I just pulled off the car today.

Better to pay $33 USD for the Volvo OE roller and put it on your existing tensioner mechanism.