Another common area of misconception is proper engine storage. Some of the confusion comes from the fact that the Corvette has been around for almost 50 years. During those 50 years, automotive technology and electronics have experienced enormous growth and change. As a result, different generations of Corvette have different needs when it comes to care and maintenance.
Based upon conversations we had with owners of both old and new Corvettes, the majority of owners of Corvettes prior to the 1984 model year prefer to remove their spark plugs and squirt a small amount of motor oil into the cylinders. In order to understand why they do this, you need to understand the general purpose of an engine lubricant.
The main function of motor oil is to reduce friction between two metal surfaces in motion. Some of these metal surfaces can have microscopic high points or peaks. When these metal surfaces rub together, enough heat can be produced to actually weld those peaks together. The peaks can be broken off, dragged and re-welded over and over again. This is known as scuffing, which can eventually cause permanent engine damage.
Over time, the lubricant film that lines the cylinder walls underneath the piston, gradually recedes leaving the walls exposed. As the piston travels up and down the cylinder upon startup, a few critical seconds exist where two metal surfaces are rubbing together without proper lubrication. You now have an ideal environment for scuffing to occur. To prevent this, owners believe that removing the spark plugs and squirting a small amount of oil into each cylinder can help prevent this from occurring. It all seems to make sense, right?
If it did, we would expect the owners of newer Corvettes to practice this same method. Not so. Based upon conversations with owners of 1984 Corvettes and up, other than changing the oil and filter, removing the spark plugs and adding a small amount of oil to each cylinder was rarely mentioned. This could be due to several possibilities. Are the spark plugs much harder to reach on an LT1 or LS1 engine as compared to an old 1968 L36 big block? Or has technology advanced far enough that today's engines are able to stay lubricated longer during extended periods of inactivity? To help us understand the proper way to prepare an engine for long-term storage, we spoke to David A. Scott, Senior Service Engineer, at General Motors Service Parts Operations. He suggested that if an engine is to be stored for nine months or longer, "remove the spark plugs and add approximately one (1) ounce of engine oil to each cylinder. The engine should be rotated just after adding the oil to the cylinders. The purpose of this step is to coat the cylinder bore to protect against rust formation during storage. Also note, this procedure is repeated after extended (18 months and longer) storage before start up. These steps were recommended by both the Base Systems Engineer and the Fuels and Lubricants Engineer."
Owners of older Corvettes usually unplug and sometimes remove their batteries during long periods of storage which they feel works well for them. If you choose to remove the battery, do not place the battery directly on a concrete floor. Concrete has a tendency to discharge a battery which is the exact same thing you're trying to avoid by leaving it connected to the car. Use a piece of wood between the battery and the floor. Because batteries produce hydrogen gas which is flammable, do not store the battery where it will be exposed to open flame, or where it is exposed to children.
Some owners of newer Corvettes (1984 to the present) feel that battery disconnection and/or removal isn't a good idea given the large amount of onboard circuits in newer Corvettes. They prefer to use a "Battery Tender". The Battery Tender, produced by Halon Marketing, Inc., is a 1.25 amp battery charger capable of fully charging a battery and maintaining the batteries optimal charge. The unit is small, compact and comes with a 5-year warranty from the manufacturer.
We asked David Scott at GM if battery disconnection was a viable option for newer Corvettes. "Actually, it is because there are circuits using power when the vehicle is "off". Without a "Battery Tender" as you mentioned, the circuits would drain a battery in about 30 - 40 days. General Motors does not require / mandate that an owner have a charger going. We have typically recommended disconnecting the battery."
Make sure to top off all fluid levels. These include coolant, brake fluid, clutch/transmission fluid and most importantly, oil and fuel. Over time, motor oil can become contaminated by dust, condensation, and even antifreeze and metallic shavings. Some motor oils contain additives which can break down over time and also act as contaminants. As these contaminants accumulate in the oil, sludge can form which will gradually adhere to internal engine components, causing your engine to perform less efficiently. Left long enough, this sludge can cause permanent engine damage. Combustion gases can also accumulate in the oil that will gradually lower the pH of your oil making it more acidic. Even if you only put 1,000 miles on your Corvette per year, make sure that you always change your oil and filter before placing it in long-term storage.
To do this, start and run the engine until it is brought up to normal operating temperature. If your Corvette is equipped with air-conditioning, the AC unit should be operated during this final engine warm-up to lubricate the compressor seal. Drain the oil and replace the filter. Refill with the type of oil recommended in your factory owner's manual. Last but not least, if you own a newer Corvette equipped with the engine oil life monitor, remember to reset the "Change Oil Light" as instructed in your owner's manual.
Another important step is to make sure you top off the fuel in the tank and add a fuel stabilizer. Some owners prefer to completely drain the fuel tank and lines, but this may be an open invitation for condensation to build within the fuel system causing premature corrosion. Most fuel stabilizers, such as Stabil, can be purchased at any mainstream automotive parts store.
If your Corvette is carbureted, you should drain the carburetors of any residual gasoline. Remaining gasoline can evaporate and turn into a varnish that can coat and eventually clog the internal parts of a carburetor.
One of the biggest problems with long-term automotive storage is rodents. Depending on how secure the facility is that you store your Corvette in, one fact remains.... it's a source of protection from the elements for both your Corvette and those furry little critters. Most owners don't realize it, but certain brands of spark plug wires can become a meal for mice. Some brands (including GM brands) consist of a silicone inner jacket that surrounds the carbon suppression core. The silicone inner jacket is then surrounded by a vegetable oil based insulating outer shell which mice find particularly appetizing. To help prevent them from making a meal out of your Corvette's ignition system, place some mothballs in and around the engine compartment, but remember to remove them before starting up the car!
Mice and other small rodents like to build nests in very small spaces and your Corvette's exhaust tips and mufflers make a perfect home. Use a couple small face cloths and rubber bands to seal off the exhaust tips on your Corvette. Simply cover the opening of each tail pipe with the towel and wrap a rubber band around it.
"Should I cover my Corvette while it's in storage and if so, what's the best type of cover to use?" This is one of the most commonly asked questions when it's time to store your Corvette. The answer depends upon where the car will be stored. If it's stored within a garage or similar shelter, it's not necessary unless the car will be stored for an extended period of time and you would like to keep the dust off of it. If the car is stored outdoors, it is recommended that you keep the car covered. Remember to periodically remove the cover, especially after a soaking rain, so that air has a chance to circulate and properly dry the car and cover.
The type of cover you should use, again depends upon where the car will be stored. If it's stored indoors, a simple cotton based cover is sufficient to keep dust off the car. If it's stored outdoors, you should consider using a Dupont Tyvek or Evolution-3 type weatherproof cover to protect against the elements. These covers can usually be found at either your local automotive parts store, or through mail order companies such as Mid America Motorworks.