SteveDoten

One of the most notorious issues with the C5 LS1/6 motors:

Crank pulley wobble or complete seperation/failure

Crank pulley is made up of an inner aluminum hub with an outer iron ring, the two parts are held together with an elastomer/rubber.

After checking the VIN #'s and paperwork when looking to purchase a C5, the first thing I would check is the crank pulley at idle for 'wobble'. It's extremely common.

The pic below is a pulley after spending some time in a bonfire, you can see the outer ring intact with the aluminum pulley melted away. Of course this is expected, but just showing the pulley is 2 COMPLETELY SEPERATE PARTS.

The 2nd pic shows the very common crank seal wear, I won't get into the 'root cause' of the GROOVE, but will speculate the OLDER grey crank seals were cutting into the pulleys.

ALWAYS pin the crank pulley, it's 100% on any Supercharged installation, I make it 100% any time the crank pulley is removed/installed.

SteveDoten

IF YOU HAVE PICS/VIDEO OF A FAILED PULLEY, PLEASE POST THEM UP, it's better to have more aware of the small issues than can make for a rough day in the life of C5 Corvette ownership. With the knowledge and right tools or a good shop, your back on the road the same day.

"Removal and Installation" of the crank pulley later tonight.

Here's the quick "take away"

1. Have the knowledge, inspect at idle for a 'wobble', this is a fore/aft movement seen from above.

2. At a minimum, REPLACE the pulley with a NEW GM OEM unit or best case, ATI or Powerbond in UD(underdrive) or standard size.

3. ALWAYS pin and correctly install/torque the crank bolt. (I'll cover this soon). ARP bolt is also an option.

4. Correct tools needed: Kent Moore FW locking tool, OTC or KM removal tool, Hawk installation tool, Torque wrench to 250-300ft/lbs, Breaker bar (again, I'll go into detail later)

SteveDoten

Crank Pinning kit:
Tool steel drilling fixture, drill bit, pins, OEM GM LS1/6 crank bolt, $99 shipped

leadfoot4

I just swapped out my OE damper for an ATI piece, over the weekend. The worst part of the job was getting the rack out and back in. What a PITA!

c5maniac2

I have an `04 Z, mine was fine but swapped it out with a Powerbond U/D since I had the motor out lol.

SteveDoten

Must be more out there?

Mattie Num Nums

Mine is going out as we speak. Its going to be fixed by A&A when I do the 8 Rib conversion on my SC. Just waiting on my Pfadt coilovers to ship.... been a long wait

mastercoryd

Too bad I didn't see this Steve already took my car apart, could've got a good clip of mine wobbling !

SteveDoten

I've been posting this for years, you could of got it the first time

mastercoryd

I'm slacking on the forums Steve lol

SteveDoten

seems a lot of people don't realize the pulleys are falling apart, but they will hear the belt noise

Yellow74c3

I'm getting some belt noise at initial start then it goes away....is this a symtom? I will look for wobble....if there is wobble will I physically be able to wiggle the pulley at all by hand if I can get to it?.....Fred

Mattie Num Nums

Mine comes and goes and seems to get better as the car heats up. It started with a screaching chirp and now my alternator isn't charging up. I am 99.9% sure the crank pulley is going out.

SteveDoten

Fred, use a flashlight and look for a lateral runout(when looking down at pulley, this will be front/back movement)

lionelhutz

When you do it watch the belt grooves of the pulley, not the front face. The front face can appear to be moving a bit making you think it's failing yet the belt grooves are running true meaning it's actually not wobbling.

Yellow74c3

I'll try to check it out tonight....Thanks for all the advice.....Fred

ZeeOSix

If there was a crankshaft seal change at the pulley location, what model year did the change take place?

Yellow74c3

Checked my pulley for runout finally and see none...Fred

SteveDoten

GM actually changed,

water pump gaskets (orange to black)
front cover gasket (orange to black)
oil pan gasket (from grey to black, much thicker seal)
front crank seal gasket (from grey to black)

I believe it was the 2004 MY(model year), I just swapped another 2003 cam prior to Carlisle, that car had the 'National' grey crank seal

FruiTay

I Just had two pulleys changed in my 01 Z for what sounded like a chirping belt. The noise would be intermittent for a while than more persistent after some time. It was right about 50,000 miles on the motor.
Thank you for sharing this Steve!