Exclusive Content
Original Shows, Motorsports and Live Events
Try it free for 14 days
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
Subscribe to the Free

1980 Chevrolet Corvette C3 - Tech Corner

1980 Chevrolet Corvette C3

James Berry Aug 1, 2009

Question: I have an '80 Corvette. When it rains, the carpet under the front floor mat gets soaking wet. I think the leak is coming from the windshield area. Do you have any idea what could be causing it?
Via the Internet

Answer: A leaking front windshield is a very common problem with C3 Corvettes. The windshield frame does not drain water properly. Debris collects in the channels under the exterior moldings, creating a perfect atmosphere for corrosion to occur. Your water leak is most likely caused by the corrosion that has taken place in the windshield frame.

The easiest way to check for a problem is to look at the frame between the glass and the windshield molding and inspect for any signs of rust or deterioration. To properly repair your Corvette's windshield frame, the windshield will need to be removed, and the entire frame will need to be cut out and repaired with new sections. Fortunately, these pieces are available from many aftermarket suppliers.

Question: I have a question about my '99 Corvette. The passenger-side seatbelt is all the way out and will not retract. Have you heard of anyone else with this problem?
Bobby M.
Via the Internet

Answer: This is a common problem on the C5. Basically, the webbing is twisted. Chevy issued a Product Safety recall-No. 00034-which includes all '97, '98, '99, and many '00 model Corvettes. You'll need to have your local dealer check his electronic file using the car's VIN to confirm whether your vehicle is included in the campaign. You can also call Chevrolet customer assistance at (800) 222-1020.

The recall will have the dealer install a guide kit in the seatbelt. If your car is not covered or already has the guide kit installed, you may simply need to untwist the belt by following these steps:

1. Remove the sill plate by lifting and unsnapping the clips from the door.2. Remove the sill plate from the hinge pillar by lifting and unsnapping it.3. Slide the sill plate from under the hinge-pillar trim.4. Remove the lock-pillar trim by gently pulling the panel away from the lock pillar.5. Slide the lock-pillar trim from under the rear-compartment side-panel trim.6. Remove the lock-pillar trim from the seatbelt webbing.7. Pull the lap-belt webbing out of the retractor and remove any twisted areas.

Good luck.

Question: When I take off from a stop in my '02 Corvette, I hear a popping noise. I was at a Corvette show and ran into a guy who had the same problem. He said that the dealer had installed a new type of rear-axle fluid in his C6. Can I use this fluid in my C5, and will it help with the popping noise?
Via the Internet

Answer: General Motors did release a new rear-axle fluid in early 2008. The new fluid is called Dexron LS Gear Oil 75W90, and it carries part number 88862624 in the U.S. (PN 88862625 in Canada). This fluid can be used in all Corvettes from '97 through current production. You'll need approximately three quarts to perform the change.

While you're at it, be sure to also check for loose or broken stabilizer endlinks, rust on the rear-axle splines (which could result from a rusty or defective hub assembly), or even a loose shock bolt. Happy hunting.

Question: I'm the original owner of a '79 Corvette with 20,000 miles. The car is all stock except for some minor paint repair. I want to take it to Bloomington Gold this year, so I'm trying to find out if it would be eligible for the Survivor or Benchmark class. What do you think?
Joe Connor
Via the Internet

Answer: I think your Vette may be a good candidate for the Survivor class. I spoke with David Burroughs, founder of Bloomington Gold, and this is what he had to say:

The Survivor and Benchmark events both feature unrestored, original cars. Survivor level means the car must remain less than 50 percent restored, and the finishes (paint, plating, and so on) must not have deteriorated more than 50 percent from brand-new. Benchmark level means that not only must the car be unrestored, but also the finishes must not have deteriorated more than 5 percent from new. That means that Benchmark cars have been preserved in "nearly new" condition and not "touched up" or restored. Cars can qualify for Benchmark by first being Survivor Certified and then the next day being Gold Certified. Obviously, this becomes exponentially more difficult to achieve as the cars become older and older.

To have a Corvette Survivor Certified, a panel of Certified Survivor Judges will inspect and certify that the car meets these standards:

1. It must be at least 20 years old.

2. It must complete a 20-plus-mile road test within one hour.

3. It must remain more than 50 percent unrestored, unrefinished, and unaltered from the way it left the factory in at least three of the following four areas:a. Exterior (Paint, Trim, Glass)b. Interior/Trunkc. Underhoodd. Chassis (Suspension, Frame, Wheels)

4. It must remain with more than 50 percent of the original finishes (paint, fabrics, plating) accurate enough to be used as a color reference for restoration of a car just like it. Note: If more than 50 percent of the color is obscured, refinished, or missing, it can't be considered accurate.

Unfortunately, it's impossible to judge your car based solely on what you've told me. Although 20,000 miles sounds good, we've seen cars with 3,000 miles whose factory finishes have been "improved" to be cosmetically better than factory. This is good for winning trophies at car shows but bad for Survivor.

Although you mentioned "minor" paint repair, you didn't say anything about deterioration. So again, it would be hard for me to say whether or not you'd meet the standards. However, once you understand our standards and see some of the examples on our website (www.SurvivorCollectorCar.com), you should gain a clearer perspective on how close to Survivor or Benchmark your car might be.

Question: Is it true the Corvette plant is closing?
Via the Internet

Answer: The Bowling Green Assembly Plant did shut down again for six weeks starting in March. Hourly workers were temporarily laid off during that span. Why? Corvette sales are down 50 percent from last year. If current trends continue for the rest of the '09 model year, there will likely be fewer than 25,000 units built. (For reference, there were 40,561 Vettes built in 2007.) Sounds like it's time to support our favorite hobby by going out and buying a new Vette.


Question: What's up with the weird-looking rotors on the '09 ZR1?
No Name Given
Via the Internet

Answer: Like many other high-end exotics, the ZR1 is equipped with carbon-ceramic rotors similar to the ones used in modern race cars. This composite material consists of carbon-fiber, graphite, resin, and silicone, yielding a lightweight and very durable rotor that rarely needs to be replaced.

There are a few negatives that come along with this type of material, chief among them cost. A single carbon-ceramic rotor starts at $1,695-significantly more than a comparably sized conventional unit. The other drawback is that you need to build up heat in the rotor in order to get maximum performance.


That being said, if you want race-car-quality stopping power from your car's braking system, and you have a few thousand dollars lying around, a set of aftermarket carbon-ceramic rotors could be just the thing.

Question:I remember the '70s, when we switched from leaded fuels to unleaded fuels and gasohol. I also remember the problems we faced having older cars. In recent days I've been having dj vu, since the only fuels available contain ethanol. Everyone is talking about the benefits of these fuels, but are we going to see the same problems with our older cars as we did back in the day?
Via the Internet

Answer: There is indeed a push to increase the use of ethanol as a means to reduce fuel-related emissions and lessen our dependence on foreign oil. The bad news for the vintage-muscle car owner is that ethanol can act as a cleaner that loosens the sludge, varnish, and dirt that accumulate in a fuel tank. Once loosened, this material can stop up the fuel filter and cause an older tank to leak.

Ethanol also absorbs moisture in the fuel tank. In a car that is not driven every day, the ethanol-water mixture may separate from blended gasoline and sink to the bottom of the tank, where the fuel pickup is located. When the car is started, this mixture may clog fuel lines and block carburetor jets. It may also be incompatible with older cork or rubber compounds as well as some metals.

Ethanol also runs leaner than gasoline, so you'll need to perform some modifications to correct this. As the level of ethanol or other alcohols isincreased, the fuel efficiency of the engine will decrease. This is because gasoline has more energy per gallon than ethanol-based fuel.

An engine running on ethanol-based fuel runs at a richer air/fuel ratio than an engine running on gasoline. The stoichiometric-or chemically ideal-air/fuel mixture for an engine running on gasoline is 14.7:1; for an engine running on E85 (85 percent ethanol, plus 15 percent gasoline), the ratio is 10:1. However, if converted correctly, an E85 engine will have performance equivalent to, if not greater than, the same powerplant burning gasoline. This is because ethanol has a higher octane rating, so it can withstand much greater compression ratios as well as advanced timing.

A modern-day muscle car with computer controls should make the air/fuel-mixture adjustments needed so the engine runs its best with whatever blend of gasoline you use. Still, when switching to an alternative fuel, you may notice erratic performance or a "Check Engine" light for several miles until the computer has a chance to adapt to the change.

Got a question for our Tech Corner expert? Just jot it down on a paper towel or a lightly soiled shop rag and send it to us at VETTE Magazine, Attn: Tech Corner, 9036 Brittany Way, Tampa, FL 33619. Alternatively, you can submit your question via the Web, by emailing it to us at vette@sourceinterlink.com. Be sure to put "Tech Corner" in the subject line.



Connect With Us

Get Latest News and Articles. Newsletter Sign Up

sponsored links