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Storing 1990 Chevrolet Corvettes - Tech Corner

James Berry Nov 1, 2009
Vemp_0911_02_z Storing_1990_chevrolet_corvettes Car_cover 2/5

Question:I'll be going overseas for about a year, and I want to know what procedure you recommend for storing my two '90 Corvettes during that time. I have a two-car attached garage, and my son will be by once a week to check on the house. If necessary, he can perform some simple maintenance while I'm away.
Via the Internet

Answer:I'm going to cover this question for any Corvette owner who's planning to store his car for an extended amount of time, or even for the winter. In a perfect world your car would always be stored in an insulated building with a concrete floor, a dehumidifier, and a temperature of around 70 degrees with 65 percent humidity. If possible, it's best to start your Corvette periodically-at least once per month-and let it run for a good 20 minutes to reach operating temperature.

Sadly, we don't all live in a perfect world, and sometimes you have to take what you can get. If at all possible, don't store your Corvette in a non-insulated garage for any length of time. In colder climates the severe temperature changes promote moisture development, and moisture can cause a multitude of problems.

The following is a procedure I'd recommend for storing your Corvette in the typical insulated-but-unheated garage most of us have:

1. Start by washing and waxing your car com-pletely. If you have any chrome, make sure to polish or wax it to help prevent corrosion.

2. Vacuum and thoroughly detail the interior. For winter storage do not use any vinyl dressing, as it can cause mildew in a damp environment.

3. Check your coolant to make sure it's clean and will hold up to the climate in your area. Fill your cooling system with the correct antifreeze for your make and model. This will prevent you from having a cracked block when you retrieve your car from storage.

4. Check and fill all of your fluids to the proper (full) level. Remember that motor oil can become contaminated by dust and condensation. Some motor oils contain additives that can break down over time, so change your oil before long-term storage.

5. If your Corvette is going to be stored for more than a year, remove the spark plugs and add approximately one ounce of engine oil to each cylinder. The engine should be rotated just after adding the oil. The purpose of this step is to coat the cylinder bore to protect against rust formation. If your car is going to be stored longer than a year without starting the engine, the oiling procedure should be repeated every 12 months.

6. Check the air in your tires and inflate them to the proper level. There's no need to remove the tires.

7. If you car has a distributor cap, remove it, spray CRC or WD-40 into it, and then reinstall it on the car. This will stop moisture from forming in the cap. Lubricate all moving parts such as the throttle linkages, transmission kick-down, and so on, with white lithium grease.

8. Make sure you fill the fuel tank and add the correct amount of fuel stabilizer. After adding the fuel stabilizer, run the car for approximately 15 minutes to ensure the stabilizer has run through the entire fuel system. Some owners prefer to completely drain the fuel tank and lines, but this can cause condensation to build within the fuel system resulting in premature corrosion.

9. Clean away any corrosion that has formed around the battery, and use a Battery Tender (or comparable unit) to keep the battery charged during storage. Battery disconnection and removal is not recommended for short-term storage on '84 and newer models, as there are circuits using power when the vehicle is off. Without a Tender, the parasitic draw of these systems would drain a battery in two to four weeks. If you're storing your vehicle for more than six months, however, you may want to disconnect the battery. If you remove it, don't place it directly on a concrete floor. Concrete has a tendency to discharge a battery.

10. If you have a manual-transmission car, it's a good idea to disengage the clutch. This will keep the clutch disc from sticking to the flywheel. Simply cut a 2x4 board to fit the length from the clutch to the seat. Wrap the board in a towel and wedge it between the clutch pedal and the floorboard or against the lower front of the seat cushion area. Take care not to put anything directly on the seat cushion, as this could damage the cushion over the course of storage.

11. Place some desiccant packages in plastic bowls in the interior. Also place a plastic bowl with mothballs in the interior and engine compartment. The desiccant will absorb moisture, and the mothballs will deter rodents.

12. Jack up the car in the correct locations and install jackstands with protective pads (rubber pads or heavy towels will work) under the front and rear suspension. This will keep the suspension loaded, just as it would be if the tires were resting on the ground.

13. Lube the entire suspension-front and rear-and check the rear differential for leaks and fluid-fill level. If your car has a manual transmission, perform the same checks on the trans at this time.

14. Insert some towels in the exhaust tips. This will help keep rodents from nesting inside your exhaust.

15. Place a drain pan under the transmission and rear differential. This will catch any leaks that may occur during storage. Remember: on a vehicle with an automatic transmission that's stored for several months, the torque converter will drain back into the trans, and the fluid will overflow. (See our next entry for more info.) The pan will catch this fluid.

16. It's also a good idea to rotate the engine and the rear axle by hand once a month. This will actuate the valvesprings and keep the ring gear and pinion lubricated in rearend fluid.

17. Cover your car with a proper, inside-use car cover. You'll need a cover that will protect the car from dust. It should be made from 100 percent cotton or a cotton/polyester blend. A fleece-lined cover is preferable for use with a show quality car.

I hope this answers your question, and have a great trip.

Vemp_0911_04_z Storing_1990_chevrolet_corvettes Transmission_filter 3/5

Question:I have an all-original '84 Corvette with about 66,000 miles. About three years ago the transmission started to leak, but only when the vehicle was parked for a long period of time, such as over the winter. I place a one-quart pan under the trans before storing the car, and the pan is full by the time I take it out of storage.

I've replaced the transmission filter, gasket, and pan, but nothing has changed. I've taken the car to dealers and even to a shop that only works on Corvettes, and no one can figure out where the leak is coming from. The only telltale sign is at the heads the transmission-pan bolts, where there are some red droplets. Any suggestions?
Via the Internet

Answer:It sounds like the fluid in the torque converter is draining back into the transmission, overflowing, and coming out through the vent tube or a seal. While this is the most likely cause of your leak, there are other problems that could be to blame.

Did you look for an imperfection in your transmission pan when it was off? If the sealing flange is bent, a new gasket won't repair the leak. If you're seeing drop marks on the pan bolts, remember: The leak could be running down from a another area, giving the appearance that the pan is leaking.

It's recommended that you start your car once a month to keep the fluid circulating. If you're out of the area, have a friend start it for you. Even if you don't drive the car, let it run until it reaches operating temperature.

The following is the recommended procedure for diagnosing a transmission leak on any Corvette:

1. Verify that the leak is transmission fluid. Automatic-transmission fluid should be red in color.

2. Thoroughly clean the area you think is leaking, including any higher areas where the leak could be originating.

3. Drive the vehicle until it reaches normal operating temperature.

4. Park the vehicle over clean cardboard. The fluid spots on the cardboard will help you pinpoint where the leak is coming from.

5. If you still have a problem pinpointing the leak, you can use a specially formulated dye and a black light. Follow the dye manufacturer's instructions to determine the amount of dye to use.

6. Once you've located the leak with the black light, make the necessary repair.

Question:I just read an article about remote keyless-entry kits for '92 and earlier Corvettes. Unfortunately, I can't find any of these kits. Are they still available?
Via the Internet

Answer:One of the best kits for the Corvette was the GM-VKE, which was simple to install, required very few modifications, and could be purchased from your local GM dealer. While this kit is no longer available, there are many companies that still offer remote keyless-entry systems for the Vette.

We spoke to Greg Goeders at Spal USA. Spal offers the AS-80 (PN 345000093) Universal Keyless Entry, which fits virtually any vehicle. It comes with two waterproof remote transmitters that operate from up to 100 feet away. The AS-80 also offers blinker identification, universal power-lock control, dome-light control, and a valet function. You'll also need to order Spal's 2-Door Lock Kit (PN 37000015), which has two actuators, a wiring harness, and all necessary hardware. Professional installation is recommended. For more information, visit or call (800) 345-0327.

According to Goeders, some cutting of the factory wiring harness is required. I'll be obtaining one of these systems from Spal soon and will let you know how the installation goes.

Question:Since we ran our Q&A on ethanol, we've received several questions on the benefits and drawbacks to ethanol and E85. The most common queries include: Why does E85 burn richer than gasoline? and, Will I need to replace any components in my older Corvette, since E85 has a different stoichiometric mixture than gas? We spoke with Fritz Kayl, president of Katech Performance, and this is what he had to say:

Vemp_0911_05_z Storing_1990_chevrolet_corvettes Ethanol_pump 4/5

Answer (E85):There are still a lot of misconceptions about E85 among consumers. First, E85 runs at a richer air/fuel ratio (9.8:1) than gasoline (14.7:1), not leaner. This is the reason you get poorer fuel economy on E85 [and explains] why flex-fuel cars have not had a major impact on gasoline sales. Most people still go to the gasoline pump instead of the E85 pump for their fill-ups. Although many people claim they want to be green, most still drive by their wallets.

Next, vehicles need to be produced at the factory to run on E85. Not much changes in the actual architecture of the engine, but the seals, fuel lines, gas tanks, fuel pumps, and more all have to be compatible with the high alcohol content. Today's vehicles (excluding flex-fuel models) can only withstand approximately 13 percent alcohol. This explains why converting older vehicles to run on E85 has not caught on-there are just too many parts that need replacement.

Answer (Ethanol):Today's gasoline includes up to 10 percent ethanol. In theory, all cars should be able to run on this mixture with no driveability problems. The problems start when the percentage of ethanol increases to 13 percent or more; such fuels are harmful to conventional engines and shouldn't be used in such applications. Recently, we encountered a vehicle that was actually vapor locking due to an ethanol content of 21 percent.

As individuals, there's no way we can regulate the ethanol content of the fuel at our local filling stations. But if you think you're having a problem with excessive ethanol content, there's a simple way to check the percentage of ethanol in your fuel.

Vemp_0911_06_z Storing_1990_chevrolet_corvettes Ethanol_content 5/5

Checking the Ethanol (Alcohol)Content of Your Fuel
1. Collect a fuel sample from your vehicle's fuel supply. Use a dry, clean container so your sample doesn't become contaminated

2. Pour 90 ml of your fuel sample into a 100ml graduated cylinder. Add 10 ml of water to the cylinder. Cover the top of the cylinder with your hand and shake.

3. Allow the fuel sample to settle for 10 to 15 minutes. The alcohol will combine with the water and separate from the fuel. The alcohol/water mixture will then settle to the bottom, since water is heavier than gasoline.

4. Note the line where the alcohol/water and fuel separate.

5. Now comes the calculation, using 100 ml as 100 percent. Subtract the 10 ml of water you added at the beginning of the test. The difference between the remaining alcohol/water and the gasoline is the percentage of alcohol in your fuel.

For example, let's say your water/alcohol line is at the 20ml mark. Subtract the 10 ml of water you added at the beginning, and you're left with 10 ml, for an alcohol content of 10 percent.

On vintage Corvettes, ethanol can loosen sludge, varnish, and dirt that have accumulated in the fuel tank. These contaminants can plug the fuel filter and cause an older tank to leak. Ethanol also absorbs moisture. The ethanol-water mixture in a car that isn't driven every day may separate from the gasoline and sink to the bottom of the fuel tank, where the fuel pickup is located. When the car is started, this mixture may clog the fuel lines or block the carburetor jets. It may also be incompatible with older cork or rubber compounds and some metals.

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 Be sure to put "Tech Corner" in the subject line.



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