Greetings everyone. I am a new Vette owner, recently purchasing a 2000 convertible from an elderly gentleman who only put 11k miles on her in 22 years of ownership. Louisiana summers are extremely hot when storing a car for years on end, and I’m concerned that this beautiful car has been very neglected. I’m coming across several issues already and I’ve only had the car a few weeks. The ultimate issue is I had to have the car hauled back to my garage after what appears to be a failing Harmonic Balancer that I’ve read so much about.

My concern is, while I’ve read alot about HB wobble and eventual separation of the rubber component, mine went into a very nasty “shudder” at highway speed, CEL came on, and the engine quit on me while coasting into a parking lot. It really sounded like it threw a rod or something significant internally. I can’t tell if I have the “death wobble” and I don’t want to run the car at all until my local performance shop can get their hands on it. Oil pressure was good for a very brief restart.

Can anyone here relate to this issue before I start throwing money at it?

 

I hooked up my “AutoZone Special” Scan Tool and pulled a P0300 for a generic cylinder misfire.

Also, the car did have a pronounced belt squeal on cold start up. Went away after it warmed up. Common symptom I hear.

 

Can you see if the HB is seperating? Not hard to see at all, maybe take a pic and post it? No other codes than the misfire?

 

You don't need an external scan tool to read the codes on a C5:

 

I’ll have to take a better look. I kinda feel like it looks normal. But most everything made of rubber or crappy plastic is bad on this car. Already had to replace the shift linkage bushings due to cracking and falling off. The soft top rear glass fell out. And I had to replace the hood and trunk emblems because they were literally melted.

 

I have an '03 Z06 that I bought in 2020 with 11k miles on it. Even with the low mileage, the balancer had a little wobble to it. Rubber breaks down over time, regardless of miles. I replaced mine with a ATI balancer with an ARP bolt. Your issues are common for a 22 year old car.

I'd also recommend getting all of the fluids changed, checking the plugs and wires, and doing a thorough inspection.

 

What happened wasn't the balancer, especially if the balancer still looks OK visually.

I'm not sure what it was, but it is likely a fuel issue or an ignition issue. I assume it was still shuddering when you fired it back up?

 

if you dont see any sepaaration visually, mark the balancer with a white pen and check periodically for separation. as for your issue, follow the code.

 

So I went out to my shop to check things out again. The flatbed isn’t coming until tomorrow afternoon. The engine was hard to crank over, but did settle into a nice idle with a pronounced *thunk thunk* sound. I grabbed a good shop light and confirmed it is definitely the harmonic balancer by the obvious wobble. It appears to be bumping against the front of the engine block. So I shut it down. We’ll know more after the mechanic gets a good look at it. My dad (Long time Corvette owner/maintainer) says the crank sensor went loopy due to the slipping HB which caused the CEL and misfire.

 

I did mark the balancer, but I don’t think I’m going to take the chance out on the road. It’s about ready to separate by the looks of things. I’ll wait until the shop can get into it.

 

The inner hub and outer ring of the balancer should be flush at the front. It sounds like your outer ring has slipped back and yes it definitely needs replacing.

I'm still highly doubtful it is the cause of the misfire. Others have had the front timing cover pretty much worn right through by the outer balancer ring without the engine misfiring or stalling.

 

After the OP changes the balancer out, I'd recommend a bottle of dry gas to begin with....

 

I’ve already run a few bottles through it. I’m going to have the shop look at fuel filter and other concerns while it’s up on the lift.

 

replacing the balancer is a significant job. I would recomend several other items "while you are in there" eg crank seal, front cover seal, perhaps new water pump, new belts, inspect tie rods, new hoses....I would even send the steering rack out to turn one steering for a rebuild ($300). I replaced my balancer and less than a year later my rack started leaking. had to remove the rack a second time which is a major pain in the butt.

 

UPDATE: So my Vette has been delivered to a local LSx performance shop. Upon further investigation, it appears the cylinder misfire was due to bad fuel rail and plugged #8 cylinder injector. The rough idle affected the harmonic balancer’s actual balance and is also set to be replaced.

Thanks for the feedback!

 

UPDATE:

Car is at the shop. New harmonic balancer is being installed along with a whole new fuel rail, all new injectors, and new fuel filter. It seems that the years spent sitting in a garage were not kind to the fuel system.