Serpentine Tensioner. Replace just the bearing or the whole thing?

c good

Original poster
Member
Dec 8, 2011
521
My belt tensioner/pulley is starting to make the little whine inherent to a failing bearing. Is it better to replace the whole thing? Or just the bearing? Thanks for any input.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
The couple I've bought at the aftermarket stores were cheap enough WITH the pulley. One of them needed the bearing pushed about 1/8" to make it match the OEM positioning, but a light hammer tap on the right size socket used as a pusher took care of that.
 

signalnc

Member
Dec 28, 2012
249
FWIW I had a shop install a tensioner pulley on my '00 cherokee, 2 months later it was screaming. i took it out--made in China bearings, I replaced it with a "made in Canada". Not saying everything China makes is crap, but if you have a choice spend $10 more for North American products. Just one of the many things I've replaced since the so called mechanics worked on my vehicles.
 

Sparky

Member
Dec 4, 2011
12,927
I got a new pulley for only 10 bucks or something for mine. The tensioner itself was OK so I saw no need to replace it.

Ended up it wasn't that pulley that was making noise, guess that's what I got for not checking first and just assuming :dunce:
 

c good

Original poster
Member
Dec 8, 2011
521
Sparky said:
I got a new pulley for only 10 bucks or something for mine. The tensioner itself was OK so I saw no need to replace it.

Ended up it wasn't that pulley that was making noise, guess that's what I got for not checking first and just assuming :dunce:

What did your problem end up being?
 

meerschm

Member
Aug 26, 2012
1,079
I just changed the pulley, kept the rest of the tensioner.

I used "Goodyear 49006 Gatorback Idler and Tensioner Pulley" from Amazon.

seemed like a waste to change the rest of the tensioner if it did not need it. mine was pretty obvious it was the pulley on the tensioner. so far so good.
 

CaptainXL

Member
Dec 4, 2011
2,445
meerschm said:
seemed like a waste to change the rest of the tensioner if it did not need it

Its actually smarter in the long run to just replace the entire tensioner. Unless you like doing more work.
 

meerschm

Member
Aug 26, 2012
1,079
CaptainXL said:
Its actually smarter in the long run to just replace the entire tensioner. Unless you like doing more work.

only if it breaks.
 

CaptainXL

Member
Dec 4, 2011
2,445
meerschm said:
only if it breaks.

Its a calculated risk. They are pretty much guaranteed to fail before 150k. Mine was not broke and it still was bad at 120k. It didnt have the right amount of tension. So as you see replacing just the bearing is not recommended.For my families sake and yours I hope you do the same. Dont skimp on engine parts, especially cheap ones.
 

Sparky

Member
Dec 4, 2011
12,927
c good said:
What did your problem end up being?

The racket was coming from my alternator. My luck dictates it is never the cheap and easy fix :crazy:

CaptainXL said:
Its a calculated risk. They are pretty much guaranteed to fail before 150k. Mine was not broke and it still was bad at 120k. It didnt have the right amount of tension. So as you see replacing just the bearing is not recommended.For my families sake and yours I hope you do the same. Dont skimp on engine parts, especially cheap ones.

Mine is original with 178k miles and still plenty tight :biggrin:
 

CaptainXL

Member
Dec 4, 2011
2,445
Tight? Do you actually know how to check a tensioner? Because I do and Im not bullshitting anyone here.
 

Sparky

Member
Dec 4, 2011
12,927
Still takes as much grunt as expected to release the belt, it still swings in its proper arc, doesn't lean out of alignment, and it doesn't bounce.

I had a tensioner go bad in my old car so I'm aware of what to look for.

Maybe my luck is better on some things lol.

I really don't know how much an entire tensioner costs vs just the pulley. The tensioner for my old car was almost $100 so that's what I had stuck in my mind. $10 vs $100 and the pulley is the only issue? I'd go the $10 pulley. If these are a lot cheaper and not much more than the pulley then yeah, it would probably make more sense to do the whole thing.
 

meerschm

Member
Aug 26, 2012
1,079
CaptainXL said:
Tight? Do you actually know how to check a tensioner? Because I do and Im not bullshitting anyone here.

Would be nice to explain how to "properly" check tensioner operation.

failure modes seem pretty simple, either the spring breaks, or the pivot locks up.

the tensioner at GMParts East is $68.20 plus shipping.

http://www.gmpartseast.com/Page_Pro...railblazer;2003;4WD&CatalogCode=56S&Year=2003

amazon has it for $59.84 with free shipping.

http://www.amazon.com/dp/B0049Z6W3G/?tag=gmtnation-20

pulley was closer to $15.


and here is some propaganda, er,... literature regarding some less expensive tensioners.

http://www.gates.com/oreilly/tech_tips/Alert Flier 3.12.10.pdf
 

dfc739

Member
Jul 29, 2012
170
Des Moines, IA
meerschm said:
Would be nice to explain how to "properly" check tensioner operation.

failure modes seem pretty simple, either the spring breaks, or the pivot locks up.

the tensioner at GMParts East is $68.20 plus shipping.

2003 Chevy - TS0120801 Pulleys & Belts/Accessory Drive LL8M30T15506

amazon has it for $59.84 with free shipping.

Amazon.com: ACDelco 12573024 Drive Belt Tensioner: Automotive

pulley was closer to $15.


and here is some propaganda, er,... literature regarding some less expensive tensioners.

http://www.gates.com/oreilly/tech_tips/Alert Flier 3.12.10.pdf

I got the tension arm assembly Gates Drivealign from O'Reilly Auto for $42 plus tax. It's worked well so far.

I would also like to know how to properly test these.
 

CaptainXL

Member
Dec 4, 2011
2,445
meerschm said:
Would be nice to explain how to "properly" check tensioner operation.

failure modes seem pretty simple, either the spring breaks, or the pivot locks up.

That's right. The Teflon inside the tensioner gets worn out over time. Not saying you can't get a new pulley for the tensioner but my argument is that it would be better to just replace the entire thing regardless if it "seemed" to still be good. If in doubt you can always use the Kirkit gauge. Dayco has some good videos.

[video=youtube;z11wfc-0-hY]http://www.youtube.com/watch?v=z11wfc-0-hY[/video]
 

meerschm

Member
Aug 26, 2012
1,079
the question still unanswered is what the tension specification is?

the Krikit will provide a measure of tension, but without a number to compare against, it would be difficult to know.

with the TB tensioner, tension will also depend on the length of the belt, and proper orientation and full pulley engagement of all the accessories. ( I imagine the spring has a range of torsional values over the range of normal operation)

my service manual has a section on drive belt tensioner diagnosis. I paraphrase below:

don't let it snap to the free position, you might might break it. (not to mention your finger if it was in the way)

Tensioner will move during operation. do not replace because the arm moves.

1 remove belt

2 move tensioner through its full travel.
-movement should feel smooth
-there should be no binding
-the tensioner should return freely

3 If any binding is observed, replace

4 install belt

so if it is broke you should replace it.

if you are really worried, you can replace it.

I can see both sides, replace cause it is old and might break.

and, if it aint broke, don't fix it.:wink:
 

CaptainXL

Member
Dec 4, 2011
2,445
meerschm said:
and, if it aint broke, don't fix it.:wink:

This line of reasoning doesn't apply to preventative maintenance. Replacing the idler pulley, belt and tensioner are considered preventative maintenance.

This line of reasoning would be analogous to replacing spark plugs only after they stop firing.

Goodyear and other manufacturers recommend replacing the tensioner when the belt is changed.

Belt tension is 150 lbs.
 

meerschm

Member
Aug 26, 2012
1,079
CaptainXL said:
This line of reasoning doesn't apply to preventative maintenance. Replacing the idler pulley, belt and tensioner are considered preventative maintenance.

This line of reasoning would be analogous to replacing spark plugs only after they stop firing.

Goodyear and other manufacturers recommend replacing the tensioner when the belt is changed.

Belt tension is 150 lbs.

where did you get the spec for the tension? and is that typical, max, or min?

and I would suggest that there are scheduled (preventative) maintenance actions, which include changing fluids, filters, and as you point out, spark plugs. but the other items are really a judgement call with replacement on observed failure to properly operate. some give you advance warning if you pay attention, some do not. some cause more expensive failures, some do not. (nothing I can think of on the TB like a timing belt on an engine with valve interference on many cars which motivates regular timing belt changes which are preventative maintenance, and in that case, I would agree that the timing belt tensioner should be replaced with the belt.)

If I changed everything which could go wrong, i would soon exceed the value of the TB (for a second time, since I ended up paying through the nose for my fuel pump r&r) do I spend $50 now, or save it for the next thing, or for the next car?
 

CaptainXL

Member
Dec 4, 2011
2,445
meerschm said:
where did you get the spec for the tension? and is that typical, max, or min?

I just found it looking around. According to Autozone the proper tension for a new serpentine belt is 180 -200 lbs. I've seen 150 -120 as the low range.

meerschm said:
If I changed everything which could go wrong, i would soon exceed the value of the TB

That's a bit pessimistic. In reality there are only a handful of critical items that wear at a rapid enough rate and have a tendency to fail repeatedly. Mainly those items on a car which move at a high rate and are prone to neglect by the average owner which would include (but not limited too) the fuel pump and accessory pulley bearings.
 

meerschm

Member
Aug 26, 2012
1,079
CaptainXL said:
I just found it looking around. According to Autozone the proper tension for a new serpentine belt is 180 -200 lbs. I've seen 150 -120 as the low range.



That's a bit pessimistic. In reality there are only a handful of critical items that wear at a rapid enough rate and have a tendency to fail repeatedly. Mainly those items on a car which move at a high rate and are prone to neglect by the average owner which would include (but not limited too) the fuel pump and accessory pulley bearings.

Sounds like time for a new thread.
 

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