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Serpentine pulleys

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
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mar601
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Serpentine pulleys

Post by mar601 » Wed May 20, 2020 1:27 pm

Need to place an order for parts today and one final thing --
98 S70 with 160K and wondering if the the serpentine belt idler pulley and/or the tensioner pulley generally need to be replaced? a good idea? -- thank you

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misha
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Re: Serpentine pulleys

Post by misha » Wed May 20, 2020 1:35 pm

If they don't make noise and have no play....i would leave them alone.
Mine are still original and i'm on 3rd serpentine belt replacement...from new.
I just inspect them when i'm replacing the belt.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

mar601
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Re: Serpentine pulleys

Post by mar601 » Wed May 20, 2020 2:41 pm

Thanks! that's the answer I was looking for.
Let me ask this, I remember at one point during the cold winter, I was getting some noise from one of them -- the one that's enclosed which I imagine is the tensioner pulley, and I very carefully sprayed a bit of WD40 inside of it through that slit. Ever since then, no noise at all.
But then again, does that make sense or not? Didn't spray much in there and it was whining pretty bad. Like I say, no problem since and that was a couple of years ago. (!) ? -- thanks for the help

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Re: Serpentine pulleys

Post by misha » Wed May 20, 2020 2:55 pm

The bearing on the tensioner pulley have protective membrane(seal).Wd-40 couldn't get into it without dismantling.
If you want....you can remove tensioner arm,it is bolted with 2 bolts to the engine and then remove the pulley which is held with big torx bolt....but first release the tension and remove the belt....or just pull it off from power steering pulley.

Be carefull with that torx not to strip it and carefully pry out the protective seal from the bearing,put a lot of grease in it on both sides...one by one.Just regular lithium grease(green) for bearings.
Grease and close one side at a time.

If it have no play,re-grease it and it will last forever.
These users thanked the author misha for the post:
mar601
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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Re: Serpentine pulleys

Post by erikv11 » Wed May 20, 2020 3:29 pm

Release the serp belt.

Spin the pulley by hand, if it spins freely and does not slow down quickly, it could benefit from maintenance (see misha suggestions) or replacement. Most are freewheeling by now and need service.
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'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 145k
'98 S70 NA, 220k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 286k
'06 S60 R, 167k
'99 Camry V6 :shock: 125k
gone: '96 NA 850 210k, '98 NA V70 182k

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Re: Serpentine pulleys

Post by June » Sun May 24, 2020 3:54 pm

One thing nobody has mentioned, if the serpentine belt jumps it is highly likely to take out the timing belt. So a few bucks saved now by not just replacing a questionable tensioner may cost you a engine. Below are photos of another users engine who's belt took out the timing belt. June
Attachments
20200524_174253.jpg
20200524_174114.jpg
My Volvo cars owned
1989 740 GLT ordered
1994 850 4door standard shift ordered
1996 960 ordered
1998 S90 ordered totalled after 3 weeks
1998 V70 GT dealer stock car
2002 S80 T6 ordered totalled
2004 S80 T6 dealer stock car and current car owned

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misha
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Re: Serpentine pulleys

Post by misha » Sun May 24, 2020 4:33 pm

That scenario is possible but that is rare.

It usually happens when serpentine belt is old and damaged,have cracked channels,and it start to slice itself on the crankshaft and ac pulleys,then it breaks and enwraps itself around the crankshaft blocking it,which leads to timing belt failure.

There is a little protective plate under the crankshaft which protects timing belt route from this possibility.
Owners or mechanics usually remove it and throw it away when they do a timing belt job,not thinking that it's there for a good reason.

Serpentine belt must not have cracks on it and it's replacement interval is the same as for timing belt.

It never breaks without a warning(squeal,humming) and if neglected...it can lead to failures like this.

If tensioner fails it will light up a battery warning light and it will lead to immediate loss of power steering.
Serpentine belt idler pulley will also not fail unexpectedly without a loud warning of dry bearing.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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June
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Re: Serpentine pulleys

Post by June » Sun May 24, 2020 4:53 pm

misha wrote:
Sun May 24, 2020 4:33 pm
That scenario is possible but that is rare.

It usually happens when serpentine belt is damaged,have cracked channels,and it start to slice itself on the crankshaft and ac pulleys,then it breaks and enwraps itself around the crankshaft blocking it,which leads to timing belt failure.

There is a little protective plate under the crankshaft which protects timing belt route from this possibility.
Owners or mechanics usually remove it and throw it away when they do a timing belt job,not thinking that it's there for a good reason.

Serpentine belt must not have cracks on it and it's replacement interval is the same as for timing belt.

It never breaks without a warning(squeal,humming) and if neglected...it can lead to failures like this.

If tensioner fails it will light up a battery warning light and it will lead to immediate loss of power steering.
Serpentine belt idler pulley will also not fail unexpectedly without a loud warning of dry bearing.
Not rare according to Volvo as the later 2.5T get a serpentine belt tensioner suggest with the timing belt service due to common failures taking the timing belt out. I personally have overheard customers getting the bad news too many times while I was in for service for it to rarely happen.

You nor I can predict what will happen WHEN his old failing tensioner let's go. Also the tention portion can be weak at this point and allow the belt to jump. I felt the OP should be aware of the possibility of engine damage from saving a few bucks now. Assuming it's not a junker on its last leg that is.... June

p.s. that belt pictured had 12K on it. So no cracked old belt shredding, but failed tensioner did take it out.
Attachments
20200524_173825.jpg
My Volvo cars owned
1989 740 GLT ordered
1994 850 4door standard shift ordered
1996 960 ordered
1998 S90 ordered totalled after 3 weeks
1998 V70 GT dealer stock car
2002 S80 T6 ordered totalled
2004 S80 T6 dealer stock car and current car owned

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misha
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Re: Serpentine pulleys

Post by misha » Sun May 24, 2020 5:04 pm

But OP asked about serpentine belt tensioner pulley and idler pulley...not the tensioner itself.

Pulleys are both replacable and maintenable as a regular service on proper mileage interval.

Off topic a bit...
I had brand new Gates serpentine belts failure in a 6 months on some of other cars...but NEVER with Conti or OE belts.

Idler pulleys and tensioners were not the culprits because Conti belt installed after Gates failure is still on....2 years after with no sign of wear and tear.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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