The Cooling SystemStart the car and let it warm up long enough for the thermostat to open and the cooling fans to kick on. Ask the seller whether the car has a history of overheating. The electric fan relay is notorious for failing, but it's a pretty easy replacement. Also ask whether the car leaks coolant, another common problem. Note that the "LOW COOLANT" light on the dashboard is prone to illuminating even when the system is full, usually due to a faulty sensor. If the light remains on, check the level in the overflow tank. If it's good, it's probably a sensor problem.
Wheel BearingsAsk the seller when they were last serviced. They're in a sealed hub and are known for wearing out earlier than they should. If they haven't been replaced in the last few years, they'll at least need to be inspected, and probably replaced, for good measure.
Rear AxleIt can leak, particularly on earlier C4s, so ask the seller about it and whether the seals have been replaced.
Carpets and Seat UpholsteryThese are known for wear, especially on the driver side, where hoisting oneself out of the car can cause friction along the leading edge of the bulkhead carpet and outboard seat bolster. Replacements are plentiful, but they cost a few bucks, especially leather seat covers.
ElectricsC4s are notorious for electrical gremlins, so push every button and switch to make sure everything functions properly. Don't assume the power windows or locks work, either, because there's a decent chance they won't. And don't forget the headlight switch. Make sure the lights open and close without a problem.
DashboardThe electroluminescent instrument panels used in the C4 have had issues with erratic gauge readouts--particularly a tachometer that reads too high--and reduced display intensity. That goes for both the original, fully digital IP and the 1990-up mixed analog/digital design. A few companies offer very effective rebuild services for both designs, but removing one of these units is a pain.
Airbag Warning LightA failure here will cause the lamp to stay illuminated, glowing bright red as "INFL REST"; the safety-belt warning lamp will usually light up, too. A bad sensor somewhere is usually the cause, but you'll need a code reader to track it down.
Tilt Steering ColumnThere's a good chance the knuckle on it is worn out, usually as a result of drivers using the steering wheel as leverage when pulling themselves out of the seat. Tug the wheel down toward the 7 o'clock position. If it rattles or feels loose, or if the wheel jiggles in your hands over bumps during a testdrive, the knuckle is worn and needs to be replaced. It ain't the easiest of repairs, either.
HeadlinerOn coupe models--even those with low miles--there's a good chance the fabric on the headliner is bubbling in places or drooping.
On the exterior, check for obvious signs of body damage, such as panel misalignment and mismatched paint, as well as details such as the finish on the aluminum wheels. If it's peeling, it will cost you a few hundred bucks to have the rims refinished. (Aftermarket wheels are another, slightly more expensive option.) Also, the weatherstripping and dew wipes are common wear items that look unsightly and could allow water to get into the car.
Deal or no deal: a tale of two C4sLast summer, we stumbled on a Polo Green '93 automatic coupe at the Mecum auction at Bloomington Gold. At a glance--the way most prospective buyers would have seen it in online photos--the car looked clean and straight. But the closer we looked at it, the more it scared us. It was clear the car had led a hard life, and had probably been in at least a minor accident. From just a five-minute walk-around, we discovered:
Worn tires that needed replacement, mounted on scratched wheels with peeling clearcoat
A front fascia with an ill-fitting license-plate filler and cloudy turn-signal lenses that didn't fit correctly within their housings, evidence of some quick-and-dirty masking work during a re-spray
An interior with missing and/or poorly fitting trim pieces and obvious replacement parts with colors that didn't quite match
Mismatched door panels--including an all-tan passenger door panel and a black-and-tan driver's door--with door-pull sections that weren't attached to either
Missing exterior emblems, broken cargo-shade mounts (and a missing shade), goofy red coolant hoses held in place with Home Depot worm clamps, and more
The car was a disaster and would undoubtedly have proved a money pit for the buyer. Surprisingly, it was bid to $5,500 on the auction block in front of knowledgeable enthusiasts. Even more surprisingly, it didn't meet the reserve, and the seller drove it away as a no-sale. He should have taken the money and run, before the high bidder realized what a pile he'd just purchased.
We'll contrast that scary '93 with a more reasonable and honest '90 coupe that recently sold in Tacoma, Washington, for only $6,000. It was a rare six-speed manual car in Competition Yellow (one of only 278 yellow cars built that year) and equipped with the Z51 suspension and G92 performance axle ratio (3.07:1). The seller had owned it for several years and drove it regularly. He'd done the maintenance, although the car had its share of C4 maladies, including the worn tilt-steering knuckle, an airbag warning light that refused to go out, and an intermittent issue with the low-coolant warning lamp.
At about 115,000, mileage on the yellow coupe wasn't exactly low, but it wasn't crazy-high, either. The weatherstripping and dew wipes were worn, but the tires only had a few hundred miles on them, and both the brakes--complete with drilled and slotted rotors--and the clutch were recent. All in all, it was about as desirable as low-priced, driver-quality C4s get.
It's clear that despite there being only a $500 difference between the no-sale price of the '93 and the sold price of the '90, the cars were worlds apart in terms of quality and return on investment. Hell, just the cost of putting tires on the '93 more than wipes out the difference between the two--and that's before any of the other big problems are addressed.
Clearly C4s are inexpensive, but there's a difference between buying a car cheaply and buying a cheap car. You won't have to spend much to get a very nice C4, so take your time and find the best one you can afford. Spending a couple thousand dollars more up front will definitely pay dividends in the long run. And never, ever buy one of these cars without a thorough inspection.
A C4 could be the bargain of the decade--as long as you do your homework.
C4 ZR-1 How Low Will the Market Go?To a certain generation of enthusiasts--specifically, those in their early-to-mid 40s--the C4 ZR-1 still generates goose bumps like few other cars. They came of driving age at a time when automotive performance was still recovering from its smog-choked nadir a few years earlier. Then, in 1986, rumors began to circulate about a "king of the hill" Corvette armed with unique styling and supercar speed.
In the fall of 1989, the ZR-1 was unleashed as a '90 model. The car was an immediate success, but it was a bright star that burned out quickly. Its performance stats were unprecedented, but a year after its launch, all Corvettes received nearly identical bodywork, a move that made the $31,683 ZR-1 package seem like a really, really expensive engine option. Sales dropped precipitously.
With time, newer Corvette models eclipsed the ZR-1's performance, if not in horsepower, then in overall competence on a road course. And today's 638hp ZR1 offers more than half again the underhood grunt. Prices have since bottomed out on the C4 models, with low-mileage originals going for the high teens to low-$20,000 range.
Once those Generation Xers save a few bucks, they're going snap up those cars, especially the '90 models with their distinctive, first-year appearance. That may still be a few years down the road, but for them, the car is an icon, just like a '67 big-block roadster. You might just want to buy one now, while they're still cheap.