Never in a million years would I have thought that with less than 47,000 miles on the odometer, the balancer on a (nearly) stock 2005 Corvette would come apart. We’ve all made the unwise decision at times to add parts that we knew were going to decrease our ride’s reliability, but in a car with only a few driveline upgrades and even a factory air filter, this type of thing can catch you off-guard. I had already replaced the A/C belt once a while back, after it was ripped to shreads, and now there was a squeaking in the accessory drive. Having heard this noise before, I initially thought this had to be a bad tensioner. The Comp Cams manual tensioner was an easy solution, a phone call away, and bound to add reliability over the factory automatically adjusting one. However, with the freshly installed tensioner, not only did the noise not go away, but now the main belt wouldn’t stay on. I took a look down at the A/C belt, which was pretty mangled and out of place. Apparently that was rubbing up against the compressor (and its electric plug—yikes!), causing the squeaking. I wound up having to cut this belt off to remove it. Put the main belt back on, started the car up, and off comes the belt again.
At this point, I decided it was time to put a fresh set of eyes on it and I called for reinforcements, as usual Greg Lovell from AntiVenom came to the rescue. Greg looked under the hood with his flashlight, and within a minute stepped back in shock and said, “wooah!” While shocked at how damaged the stock balancer was, Greg said he wasn’t at all surprised that it needed fixing. Though it is more common on C5s, if I had a nickel for every wobbly Corvette balancer that has been replaced I might be able to pick up a second C6 or a fifth-gen. That being said, I decided it was high time to look around the car for some other trouble areas and show the best way to fix them. Of course we didn’t have to look far to notice the water pump was leaking, perhaps a casualty of the wobbly balancer. Still at the front end, it was easy to see the cracks around the factory drilled rotors. With the heat and stress that the front rotor in particular sees, perhaps a dimpled or slotted rotor would be much better. Next on the list, I happened to notice a crack or hole in one of the CV boots (on the left rear axle), which was slinging grease all around the wheel and control arms. It was just a matter of time before the grease ran out, and the bearings were shot. Once these issues were all squared away, I planned to put many more miles on the C6 and begin some light modifications.
Replacing the automatically...
Replacing the automatically adjusting (spring loaded) factory tensioner is definitely not a bad idea, if you would like to increase reliability in the long haul. Many consider this a must on supercharged applications where belt slip can be an issue. Comp makes a very nice manual tensioner (PN 5401) for the LS2, which is made from billet aluminum and costs just under $155. We recently used the F-body version on our STI Killer.
As seen here, the Comp tensioner...
As seen here, the Comp tensioner locks into place using a socket or wrench. [Photo by Kevin Clarkin]
To replace the factory balancer,...
To replace the factory balancer, a number of things must be removed from the front of the engine to gain access. Among them is the rack-and-pinion, so technician Kyle Miller of AntiVenom got to work on unbolting the steering shaft and draining the rack.
Kyle then started unbolting...
Kyle then started unbolting some of the coolers and gently pulling them out of the way.
The subframe was even lowered...
The subframe was even lowered down a good bit, without completely removing it, for further access.
This is especially important...
This is especially important on Z51 models, which have even more front end clutter.
At last the steering rack...
At last the steering rack is liberated, allowing Kyle to get the air gun into the engine bay to remove the balancer bolt and balancer.
Side by side it is easy to...
Side by side it is easy to see that the old balancer is no longer flush on the front side as the center and outer piece seem to be separating. To keep it simple we went with a new balancer from GM, and ordering the GMPP part number (19155067) rather than the factory replacement definitely saved a few bucks.
Before bolting on the new...
Before bolting on the new balancer it was immediately apparent that the water pump had begun leaking, and there was no sense chancing that it was just the gaskets. AntiVenom replaced the stock unit with a low-mile take-off from a 2009 Z06, and they even outfitted it with a new 160-degree thermostat.