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Old Nov 28, 2019 | 05:19 PM
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When should I replace the harmonic balancer on my 99 c5. It has 124,000 miles. Balancer looks good but I have a slight seal leak.

Last edited by StudebakerJoe; Nov 28, 2019 at 05:22 PM. Reason: more detail
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Old Nov 28, 2019 | 08:08 PM
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If it’s not broke. Don’t fix it.
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Old Nov 29, 2019 | 06:02 AM
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Just had a bunch of work done on seal and gasket leaks on my 144K mile '03 Coupe. And they did change the pulley assem as well. Was very happy to pay a good shop to do it. Age sucks! LOL!
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Old Nov 29, 2019 | 07:16 AM
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Originally Posted by StudebakerJoe
When should I replace the harmonic balancer on my 99 c5. It has 124,000 miles. Balancer looks good but I have a slight seal leak.
You HAVE to remove the balancer, in order to replace the crankshaft seal. Knowing that the balancers are know to fail, and the work required to get at them, there's absolutely no sense in putting the old one back on, once it's been removed. Install a Powerbond (Dayco) balancer on, when you replace the seal
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Old Nov 29, 2019 | 10:38 AM
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I would do the front cover gasket as well since this will likely be the only time that the balancer will be off.
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Old Nov 29, 2019 | 10:39 AM
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Originally Posted by leadfoot4
You HAVE to remove the balancer, in order to replace the crankshaft seal. Knowing that the balancers are know to fail, and the work required to get at them, there's absolutely no sense in putting the old one back on, once it's been removed. Install a Powerbond (Dayco) balancer on, when you replace the seal
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Old Nov 29, 2019 | 01:18 PM
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Any examples of Powerbond (Dayco) balancer with 124000 miles on them.
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Old Nov 29, 2019 | 02:20 PM
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Whether or not you find any examples of PowerBond failures, I don't recall seeing any replacement balancer failures where the replacement was a quality unit. I also take the opposite view of "if it ain't broke - don't fix it." We'd all be driving flat head Ford V-8's if everyone thought like that. Progress comes when innovative people work to improve the status quo. If you're sure you have the OEM balancer, then I'd yank it out of there and install a better one. I do believe that "a stitch in time saves nine."

Last edited by tbrowne; Nov 29, 2019 at 02:22 PM. Reason: Fix grammer
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Old Nov 29, 2019 | 02:37 PM
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Originally Posted by tbrowne
I also take the opposite view of "if it ain't broke - don't fix it." We'd all be driving flat head Ford V-8's if everyone thought like that. Progress comes when innovative people work to improve...
you better replace your entire car then. Lol. There’s been a lot of improvements in the last 20 years.
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Old Nov 29, 2019 | 02:56 PM
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Originally Posted by Chillo32
you better replace your entire car then. Lol. There’s been a lot of improvements in the last 20 years.
Getting back on topic, let me ask you a VERY important question....have you ever removed the harmonic balancer, from a C-5 Corvette? If you haven't, I can assure you, from personal experience, it's NOT a "day at the beach". There's a fair amount of disassembly required, to get at it. And if you have removed one, why the hell did you put a known problematic piece, back on the car??
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Old Nov 29, 2019 | 05:59 PM
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Originally Posted by leadfoot4
Getting back on topic, let me ask you a VERY important question....have you ever removed the harmonic balancer, from a C-5 Corvette? If you haven't, I can assure you, from personal experience, it's NOT a "day at the beach". There's a fair amount of disassembly required, to get at it. And if you have removed one, why the hell did you put a known problematic piece, back on the car??
about a 3 hour job. Not that bad.
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Old Nov 30, 2019 | 05:52 AM
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Originally Posted by Chillo32
about a 3 hour job. Not that bad.
20 yrs ago > Oh heck yes, let's get er done. Now days > 76 yrs old, bad back, plus other stuff > Where's a good shop I trust. ha ha ha ha .
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Old Dec 1, 2019 | 07:24 PM
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124K miles. That has to be a record. 20 years old, Wow!!!.. It cant be running true... Are you sure that its never been changed before ?....
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Old Dec 1, 2019 | 07:45 PM
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[QUOTE=Josephu;1600581648]124K miles. That has to be a record. 20 years old, Wow!!!.. It cant be running true... Are you sure that its never been changed before ?....[/QUOTE

not super out of the ordinary. Most of these get replaced in an abundance of caution rather than out of necessity. Plenty of balancers out there that have 150k miles on them.
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Old Dec 1, 2019 | 07:50 PM
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Originally Posted by Josephu
124K miles. That has to be a record. 20 years old, Wow!!!.. It cant be running true... Are you sure that its never been changed before ?....
Vhttps://ls1tech.com/forums/generation-iii-internal-engine/1928420-swapping-110k-mile-ls1-rebuild-no.html
see post #3, 4, 5


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Old Dec 1, 2019 | 08:02 PM
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Originally Posted by voda1
Vhttps://ls1tech.com/forums/generation-iii-internal-engine/1928420-swapping-110k-mile-ls1-rebuild-no.html
see post #3, 4, 5

exactly. Sometimes forums create the “oh **** I have to fix this” mentality. I saw a thread a while back where there was only one reported balancer failure that caused major damage and the car was heavily modified and supercharged. But hey, where is the mess hall? I’ll follow. Lol.
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Old Dec 2, 2019 | 01:41 PM
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When I traded my C5 in i had 174000 on the original harmonic balancer.

Last edited by bravo29; Dec 2, 2019 at 01:41 PM.
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Old Dec 2, 2019 | 03:20 PM
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136k on the clock here. Marked og balancer still looks good.
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Old Dec 7, 2019 | 10:22 AM
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When I replaced mine at 138000 the sealing surface on the balancer was grooved real bad. I would replace the balancer and seal plus all of the other pulleys and tensioners while you have it apart.
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Old Dec 7, 2019 | 11:14 AM
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I just bought an ati, all new pulleys, front seal and front cover seal. Was about $750.
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