COAL: 2003 Corvette Z06 – A Cascade Of Bad Decisions

Even now, it’s hard for me to put into words exactly how I feel about the C5 Corvette Z06. It was simultaneously one of the best cars and one of the worst cars I’ve ever owned, an example of both engineering excellence and sheer head-shaking incredulity, the source of some of my highest highs and my lowest lows.

I suppose it was a lesson that I had to experience in order to learn.

Buying the car

As I had sold my Street Touring Roadster (STR) prepared NC Miata, I needed a new ride for Sports Car Club of America (SCCA) Solo competition. I bought my ND Miata thinking that I’d run C Street in the car, but there was a little voice in the back of my head egging me on to try something that wasn’t a lightweight rear wheel drive roadster. Wasn’t it time to try something drastically different?

As luck would have it, a former STR competitor down in Kentucky had an A Street (AS) prepared 2003 Chevy Corvette Z06 (also referred to as the C5Z) for sale, and for a seemingly good price. I didn’t have any spare cash, but I did have the Apple stock I bought in 2002 as a high schooler, which had grown so much now that selling my stock could singlehandedly pay for the car. Sure, I’d be selling an appreciating asset (equity) for a depreciating asset (the car), but surely the Apple stock wasn’t going to go much higher, and the C5Z was at the bottom of the depreciation curve, right? Right? (Cue ominous music.)

The nice thing about the C5Z was that it was in a seemingly timeless sweet spot for autocross competition, with a narrow body, more than enough power from the LS motor, and nearly perfect gearing. One could run a C5Z in both the A Street class as well as the Super Street Race (SSR) class, the only difference being the mandate the run street tires in AS while one ran Hoosier autocross tires in SSR. C5Zs could hold their own — and beat! — the later C6 and C7 Corvettes.

This particular Corvette had around 85k miles on it, which I didn’t think too much of. I struck a deal with the seller and traveled down to Kentucky to pick up the car in person and drive it back home to Michigan. I took for a quick spin around the block, and immediately noticed some sort of gear whine from the transmission.

I asked the seller about it, and he said the car had been making that noise since he had the exhaust installed. That’s interesting, I thought. In hindsight, I should have just scrapped everything right there and driven my rental car right back home, but V8 rumbly noises make fools of us all, and I was so intoxicated with the idea that I’d have a fast car that I pressed forward with the deal.

It’s hard to say “no” to an engine like this.


I brought the car home, enjoying the occasional stab of the throttle and the ice cold air conditioning on the long drive home.

Autocrossing the car

The good news is that it’s really hard to mess up the setup of a C5Z. The car came prepared with Koni shocks, two sets of wheels and tires, and a good front sway bar. There’s also a ton of adjustability on the car stock: it’s possible to set the ride height of each corner of the car individually, which means it’s easy to corner weight the car.

In grid at the 2016 Solo Nationals.


I didn’t get much of a chance to run the Corvette in National competition, though. Really, the car saw action mostly at local autocross events, and only really showed up on the National stage at Solo Nationals in Lincoln. I was there with my codriver, a friend who let me run his insane rotary powered MG Midget at Nats the year prior, running in AS. I coned away what would have been my first ever Nationals trophy, which was disappointing but not entirely out of character.

Tracking the car

Still, it’d be a shame if the only hard driving I did in the C5Z stopped at the top of second gear, so I took the car to a single track weekend. I went to Gingerman with a couple of friends, running the Corvette around a race track that I was only faintly familiar with.

The C5Z and my friends’ cars underneath the stars at Gingerman Raceway.


Naturally, I didn’t push the car to the limits. It’s one thing to lose control at 45 mph where the only thing to hit are cones, it’s another thing to go flying off a race track at 80 mph and into a tire wall. I didn’t disengage all of the electronic nannies, keeping the car in Competition mode for the entire weekend.

Descent into madness

What I didn’t know before buying my C5Z was that parking the car outside is a very bad idea. Why? Because when it rains, you will get water in the interior.

For the Fixed Roof Coupes, of which the C5Z is an example of, the engineers basically permanently affixed a hardtop to a convertible Corvette. However, with the passage of time, seams between the roof and the windshield frame expand, allowing water to leak past the seals, down the A pillar, onto the wide side sills, and into the foot wells.

Two heat lamps and two electric fans attempting to dry out the interior while the C5Z is parked outside.


My problem was that my 4-car garage was a full house. I had in the back my two Subaru XT Turbos, and in the front my ’66 Mustang and my ’67 Morgan Plus 4.

So the Corvette had to live outside. I got a cockpit cover thinking that would do the trick, but it didn’t. The correct answer was a full car cover to keep the water off all the bodywork entirely, but I wasn’t willing to admit it.

Eventually, after blow drying the interior for the umpteenth time, I got fed up and fire saled the car.

The for sale ad

Are you a dumbass? Does the prospect of fixing pre-bankruptcy GM crap excite you to no end? We both know the answer to both questions, and that’s “yes.” Otherwise, you wouldn’t be looking at this piece of shit C5 Corvette Z06 when you can find so many other perfectly working C5Zs for decent money. You’re thinking to yourself that you can fix all of the problems that this Corvette has for cheap and have yourself a turn-of-the-century plastic fantastic supercar for less than $16k all-in for the buy-in and repair.

If you’re smart, turn around and go find another Corvette to buy instead of this shitbox.

But you’re not. So let’s get down to the brass tacks.

History of the car

The car served the majority of its life as the daily driver of some woman down in Ohio. From there, it passed to a fellow autocrosser in Kentucky who prepared the car for SCCA competition in A Street, adding the Konis, front sway bar, and a trailer hitch. Then it passed into my hands, where I proceeded to continue beating the shit out of the car at autocross events and the occasional track day event.

So if you’re looking for a pristine driver, or a car that can be rescued into a pristine driver, this car isn’t it. The metal front protective radiator guards are gacked, the front rubber air dam bits are held on with zip ties, and there are two cracks in the front bumper from whacking pylons at speeds up to 65mph.

Ideally, this car would continue life as an autocross car, track day beater, or dedicated wheel-to-wheel race car. But if you’re a glutton for punishment, you can try to fix all the issues the car currently has and make it into a nice 15-footer for the street.

Things done to the car

Boy howdy, are there lots of problems with this car. When I go online to Google fixes for this car, what boggles my mind is how numerous and widespread the issues are, and most incredulously, the sheer acceptance of all these issues plaguing Corvettes reminds me of how Audi fanboys insist that their cars are reliable even while the interiors of their cars are lit by the warm glow of check engine lights.

Let’s first run down the list of things I’ve done to the car.

  • Replaced the hazard light switch buried in the dash. As it turns out, asking a car to have working turn signals past the 100k mile mark is too much to ask for in a car built in this millennium.
  • Replaced the front passenger DRL/turn signal socket so I could signal right turns.
  • Removed the HVAC control unit in order to resolder the circuit boards and replace bulbs so I can actually read what temperature the climate control is set at. Another common issue with these cars.
  • Replaced the radio with an aftermarket unit that also has bluetooth.
  • The “hose clamp on the rotary seat back locks” trick in an effort to keep the seat from flopping back. It works most of the time, but still sometimes flops back during autocross or track driving.
  • Replaced the passenger rear wheel bearing. I have a new spare front and a new spare rear hub that comes with the car.
  • Oil catch can for the engine.
  • Two oil changes with Redline synthetic motor oil.
  • Added trailer wiring.
  • New Continental DW tires on the wheels. Wheels are replica chromies and are pitted like hell, but they look okay from 20 feet away, and for fuck’s sake, you’ve got a new set of Corvette tires.

Things that were previously done to the car that I don’t have any paperwork for:

  • Head was serviced by no one other than Danny Popp. Car was also corner balanced, if you give a shit.
  • Car has single adjustable Koni Yellows on all four corners.
  • Car has a hitch. Apparently, nothing brings out cell phone cameras faster than a Corvette towing a trailer full of crap. You’ll be the talk of the gas station towing tires or a motorbike with this thing.

Corvette with a tire trailer hitched.


  • Dark tint that was probably okay in Kentucky that is now liable to get you pulled over in Michigan.
  • Corsa cat-back exhaust was installed, though it is currently uninstalling itself as pieces drop off the car. I do have a stock OEM C5Z exhaust that goes with the car that you can install so you can have, you know, matching mufflers in the back.
  • Car has a front sway bar, aka “Stranobar,” from Sam Strano of Stranoparts. This one is probably the smaller of the sway bars he offers.

Everything that is wrong with the car so far

I have learned very quickly that these cars don’t age well. Here’s what’s wrong so far that I know of. I’m sure that whomever buys this car will have something else fail immediately on the drive back home.

Car leaks water like a motherfucker. Apparently, it’s a common issue that plagues many C5 FRCs, of which the C5 Z06 is an example. The solution is to remove a bunch of trim and seals, and attack the seams with a tube of silicon caulk. And here I was assuming that a watertight cabin was a fundamental engineering requirement for building a car. Stupid me. Passenger foot well accumulates water much faster than the driver side foot well.

Squeal coming from the engine bay. I think it might be the belt tensioners, but if it’s not, I’ve got a crank pulley and crank bolt that can go on the car. Crank pullies are advanced technology, you see, which is why it’s a weak point and all C5 Corvettes eventually need theirs replaced. Fuckin’ hell.

Noise coming from the driveline. I suspect it’s coming from the torque tube. A good torque tube is included with the car — have fun swapping that in, either as-is or, if you’re smart, rebuilding it before you put it in. And if your luck is shit and it’s not the torque tube, it’s probably the diff. Have fun!

Passenger side power window no longer goes up and down. Fortunately, it’s stuck in the up position, so it can provide some protection against the rain until the weather overwhelms the seams on the right side of the roof, trickles water down the A-pillar, and into the passenger foot well.

Good stuff about the car

Ah yes, the only reason why the car has stuck around in my garage for so long: it’s one of the best driving cars I have ever driven.

The car, being set up as an autocross car, is perfectly neutral and eminently catchable. I have never spun this car on an autocross course or on the track, and this is coming from someone who is well known in autocross circles for being able to spin a Miata multiple times in a single autocross run. There is plenty of grip, and the car is set up to rotate easily (read: it’s loose), which makes this car a fucking hoot and a boot to drive. The steering, while slow, is weighty and communicative, and there’s nothing like the throttle response from a naturally aspirated V8.

It’s too bad the driver seat is crap and that the car cooks its engine oil after 15 minutes on a road course, but that can be solved easily with a race bucket and oil cooler if you’re willing to take this car in that direction.

And when you’re done releasing your inner child with some fast driving on a closed course — because we’re civilized adults, dammit — the car is perfectly comfortable for cruising back home. The air conditioning blows cold and the heat blows hot. At highway cruise, the car gets about 28 miles per gallon. When towing a tire trailer loaded with 300 pounds of junk, the car gets 20 miles per gallon on the highway.

So I won’t blame you if you decide to fix this car and try to use it as a regular street car, because the car is a lot of fun to drive. Even as I’m ranting about everything that’s fucked on this car, there’s a small voice inside me that whispers that the car doesn’t need a lot of work to be awesome, and that I shouldn’t sell my 400 horsepower Fisher Price plastic toy.

All you really need to do is spend a couple of weekends putting on all of the parts that come with the car. As my time is currently being taken up by a ’66 Mustang and a ’67 Morgan, I simply don’t have time to do anything to this car, so it sits, forlorn, waiting for its Prince Charming to come rescue it.

The deal

I’m asking $14,000. Yes, the car is cheap. Did you just read all of the above? It’s cheap for a reason.

I’m willing to entertain offers in person. Don’t go trying to negotiate over the phone, text, or email. I want you to look me in the eye when you make an offer, so you can see me cringe or laugh out loud. But do make offers, because I want this car gone from my sight.

Once again, if you’re smart, you’ll have read all of this and decided that you should go look at a different car. That’s good. Get lost and continue making good decisions in your life.

For the rest of you, I’ll be waiting to hear from you.

I sold the car in 6 hours after posting it to Craigslist.

Owner #4

Unfortunately, I sold the car to someone I know.

My friend Kevin called me, interested in the car. I at first refused to sell the car to him. “It feels like I’m passing an ex-girlfriend on to one of my friends,” were my exact words.

His counterpoint was that he knew what he was getting himself into, especially after reading the for sale ad. And he promised not to ring me up when something inevitably went horribly wrong with the car.

So I sold the Corvette to him for $11,000. For less than half the price of a brand new base model Camaro, he had a 405 hp turn-of-the-millennium super car. But was it a good deal?

The first thing Kevin had to do was replace the transmission, as the issues weren’t confined to just the torque tube. That took him 1.5 months and a few thousand dollars to take care of, scrambling to get the work done before Solo Nationals. It was during this time that he informed me that the car’s shifter had been cut down from stock. (Hmm… what other surprises did this “stock” C5Z hold in store?) He also finally made the car watertight by caulking the car.

But Kevin had a decent working C5Z, and he and his friends drove the crap out of the car, with a rotating cast of codrivers at every single event. The car was now nicknamed the “Li Oh Six,” a dubious honor to its former owner.

Owner #5

Kevin eventually sold the car to someone on the west side of Michigan, and I thought that that would be that. I hoped that the owner never took it to any autocross east of Lansing.

Owner #6

I was walking down grid at a Champaign County Sports Car (CCSCC) event at Rantoul, when I spotted a red Z06 with a familiar crack in the bumper right next to one of the turn signals. I circled the car once. From out of nowhere, the owner appeared, saying, “Yep, this is your old car!”

Fucking dammit.

The new owner, Devin, bought the car from the gentleman in Western Michigan, and was hell bent on running Nationally with it. Which meant that I was going to keep seeing the car again for a little while longer.

While the car was under Devin’s ownership, it got a lot of action, often double dipping in classes with many, many codrivers. The car could run SSR, AS, and Classic American Muscle Sport (CAM-S), and frequently ran at least two classes with four drivers at once. I think one time the car had eight drivers for a single event.

But all things must come to an end, and the end came when the engine done blowed up. Unfortunately for me, the cause could be directly traced to something I had done — I gronked the PCV when installing the oil catch can, which led to low oil pressure for the rear cylinders — but Devin didn’t hold it against me. He rebuilt the motor and then sold the car.

Owner #7

I got a Facebook message and a forum message from the new owner of my old car. This thing will simply never go away…

He wanted to know if it was possible to reinstall the stock radio back into the dashboard. Did I do anything irreversible when installing the aftermarket radio?

I told him that I simply didn’t remember any more. It was a half truth. If I sat down and thought really hard about what I had done while cursing GM under my breath when replacing the hazard light switch and the radio at the same time, I probably could recollect exactly what I had done years ago. But I really didn’t want to.

I haven’t heard from the new owner since. I hope it stays that way…


I was having dinner with friends after last weekend’s Great Lakes Divisional Solo Series event up in Oscoda, when the conversation somehow turned to Corvettes. Kevin was there, and I asked him if he regretted owning the C5Z.

Self portrait with the Corvette under the stars at an Oscoda Solo.


Not really, he said. I was going to own one sooner or later, and better for me to discover what the ownership experience was like with a cheap Corvette than to pay lots of money for a pricier C5Z to get the exact same ownership experience.

Sounds about right. I guess nothing cures the desire to own a Corvette better than actually owning a Corvette.

Did you know, he continued, that your old car had an [illegal] tune on it?

What, really?

Yeah, they just discovered it.

Well, damn. That old Corvette, still full of surprises.