1998 main/serpentine belt noise resolved: incorrect size specification
07-14-2008, 12:21 PM
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3rd Gear
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1998 main/serpentine belt noise resolved: incorrect size specification
For ten years, I have had different degrees of annoying noise and vibrations coming from the main (alternator) belt. During the warrantee period, various chevy dealers replaced the belt, tensioner etc, but usually the noise was back in a bit.
The specs are wrong!
I have a 1998 Conv A4. When you query the belt size on say autozone.com for the 1997-1998 model vs. 1999+ models, the 1999 belt is a fraction of an inch smaller: below 80" vs above 80". The 1997-1998 Gatorback belt number is 4060802 (meaning 80.2"), the 1999+ number is 4060798 (meaning 79.8").
In various postings, the difference between 1997-1998 and 1999+ has been pointed out, without an explanation as to why, as it seems it is only the belt that has a different part number.
Well guess what: this is wrong!
It may only apply to convertibles, which were introduced in 1998, or even automatics for all I know, but sure enough my 1998 Corvette needs the 1999 smaller size 4060798. In other words, the specs are wrong.
How to tell: I noticed the tension marker on the tensioner was below tolerance (slightly below the two markings). I had just put in a new Gatorback and it still showed low tension. Of course I'd been driving with this kind of configuration for 10 years!
So I decided that the .3 inches would make a difference, and ordered the 1999 belt. Problem solved. No more vibrations when shifting from rear gear, no more chirping, no more rattling when in idle. Tension indicator is just right.
Now one thing, when putting on the belt, it would seem to be really hard to try sliding the final piece over the tensioner.
Instead, route the belt over the tensioner already, and leave it off the small idler in the middle, the one right after the huge harmonic balancer.
You can actually stick your right hand all the way from the passenger side down there to grab the belt and slide it on the idler pulley when you are pushing the tensioner spring in. You won't be able to see the idler pulley from there, but there is definitely enough space for your hand.
The specs are wrong!
I have a 1998 Conv A4. When you query the belt size on say autozone.com for the 1997-1998 model vs. 1999+ models, the 1999 belt is a fraction of an inch smaller: below 80" vs above 80". The 1997-1998 Gatorback belt number is 4060802 (meaning 80.2"), the 1999+ number is 4060798 (meaning 79.8").
In various postings, the difference between 1997-1998 and 1999+ has been pointed out, without an explanation as to why, as it seems it is only the belt that has a different part number.
Well guess what: this is wrong!
It may only apply to convertibles, which were introduced in 1998, or even automatics for all I know, but sure enough my 1998 Corvette needs the 1999 smaller size 4060798. In other words, the specs are wrong.
How to tell: I noticed the tension marker on the tensioner was below tolerance (slightly below the two markings). I had just put in a new Gatorback and it still showed low tension. Of course I'd been driving with this kind of configuration for 10 years!
So I decided that the .3 inches would make a difference, and ordered the 1999 belt. Problem solved. No more vibrations when shifting from rear gear, no more chirping, no more rattling when in idle. Tension indicator is just right.
Now one thing, when putting on the belt, it would seem to be really hard to try sliding the final piece over the tensioner.
Instead, route the belt over the tensioner already, and leave it off the small idler in the middle, the one right after the huge harmonic balancer.
You can actually stick your right hand all the way from the passenger side down there to grab the belt and slide it on the idler pulley when you are pushing the tensioner spring in. You won't be able to see the idler pulley from there, but there is definitely enough space for your hand.
07-14-2008, 02:26 PM
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Melting Slicks
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St. Jude Donor '08-'09
the Delco book also lists the 802 for the 97- 98. any chance any of the pulleys associated with that belt been replaced with one a little smaller in diameter?
07-14-2008, 02:45 PM
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I had exactly the same problem with my '97, which I bought 3 years ago. It made quite a bit of noise, and made an annoying rumbling sound when I shifted from park to a drive gear. Also, when I shut the engine down, it made the same rumbling noise. A few weeks ago I noticed that the main belt seemed to be a bit sloppy. I changed the belt tensioner and ordered a new belt from Gene Culley, and after a 15-minute install it was like magic - no more annoying noises!!
