It’s that time of year: The nights are drawing in and for most of us the mercury outside is dropping. If you live North of the Mason-Dixon line, it also means that frost and snow are here. For many northern Corvette owners who have to endure winter weather for several months, there’s a little more to winter storage than simply driving the car into the garage, locking the door, and walking away until next April.
Cars, including Corvettes, generally don’t like sitting for extended periods and if care isn’t taken, you can be faced with all kinds of problems come spring – flat spotted tires, stale fuel, hard starting, corrosion, musty interiors – these are just some of the problems that can result from not storing your Vette properly. And it doesn’t matter whether your ride is a ’62 Roadster or a 2004 Z06 – Mother Nature has no mercy.
However, if you take the time to make a few preparations before putting your car away for winter, then once the days start getting longer and the snow begins to melt away, you’ll be able to pull your Corvette out of the garage and start driving it, instead of wasting precious spring days and nights trying to fix all the problems that resulted from not taking the time to prep it properly for storage. In this article, Corvette & Chevy tagged along with Bob Clemmens, a long-time Corvette fan, GM trained technician, and member of the Legendary Motorcar team, who showed us a few simple tasks you can perform to ensure your baby sleeps soundly and uneventfully through the winter months.
Special thanks to Bob Clemmens and Legendary Motorcar (www.legendarymotorcar.com)
Time to put your Vette away for the winter…do you know the proper way to do so?
Here’s our subject vehicle, a 1990 L98 coupe with a four-speed automatic. Recently purchased, the car has approximately 90,000 miles on the clock and is in good condition for its age. We’ll be taking a few winter storage steps to ensure that come spring, we can get as much seat time in it as possible.
Our first order of the day is to give the car a thorough inspection, to make sure there aren’t any obvious issues that are likely to get worse while in storage. As a result, we’ve brought it into the garage and popped the hood.
The L98 motor appears to be in good working order with recent replacement service items, including the plug wires and a fairly new alternator, among other things. Still, there are a few things that need to be done before we put the car away.
Because our service bay features a hoist, we’re going to jack the car up so we can have a look underneath to make sure there aren’t any problems – obvious ones include rusty brake or fuel lines, worn bushings or fluid leaks.
Although Bob says it isn’t mandatory on a C4 like this, if you choose to raise your car on jackstands while in storage, make sure you place them in the factory recommended location – usually the strongest part of the frame. This prevents damaging the floorpan or lines while the stands support the weight of the car.
One of the first things you should do before putting your Corvette away is change the oil. Clean oil provides better protection of the moving parts and also ensures that come spring, you can simply jump in the car and drive it. Make sure a catch can is in place under the pan before draining the oil.
On C4s like this, a single drain plug at the back of the oil pan needs to be unfastened in order for the old lube to pour out.
Although the oil filters in these cars are fairly accessible by modern standards, you’ll still likely need a filter wrench to pull the old filter loose.
After a good tug with the wrench, you can unscrew the filter and pull it off.
Before putting the new filter on, make sure you coat the gasket with a small amount of fresh oil. If the car is going to be stored where it gets very cold and it will be started during the winter to rotate the engine, it’s a good idea to use a thinner viscosity oil to better lubricate the moving parts – i.e. 5W30 instead of 10W30. Do bear in mind that if you generally run thicker oil you’ll need to change back in the spring before you start driving the car again.
After coating the gasket, half fill the new filter with fresh oil before installing it – use your hand to screw it in place and make sure it’s nice and tight, and a slight tighten with a filter wrench will ensure it doesn’t come off.
Then refill the engine with fresh oil, checking the dipstick to ensure it reaches the full level. Start the engine for a few seconds until the oil light goes out, check the oil level and then fill the engine until it reaches the maximum level on the dipstick.
Here we go, perfect!
The next step is to check the antifreeze, not only the level but also the composition. If your Corvette has a modified engine and you run a 70/30 water/antifreeze mix, you need to make sure that you drain it and re-fill the cooling system with a 50/50 mixture for winter; otherwise, water will expand under cold temperatures and can crack the cylinder heads and block.
A good idea is to use an antifreeze tester to measure the freezing point of the coolant – the lower the temperature is, the better off your engine will be during winter storage. As antifreeze ages, its freezing point tends to rise and its anti-corrosion properties get diluted, so it should be replaced every couple of years. From using the tester, the coolant in our C4 indicated a freeze point of approximately -35 degrees Fahrenheit, more than adequate for our needs.
Another obvious task is to fill the washer fluid reservoir. Even though many Corvettes are fair weather drivers, you can’t always avoid spring rain showers and having no washer fluid isn’t much fun when driving through a downpour.
C4 Corvettes like this one (as well as older Vettes) require periodic greasing of the front end as part of scheduled maintenance. Because the car will be sitting for several months, it’s a good idea to grease the nipples before you put it away for winter.
C4s have three grease nipples on each side – one at the top where the spindle attaches to the control arm…
One at the bottom where it attaches to the lower arm, and another where the spindle meets with the outer tie rod end.
C4 and newer Corvettes use composite leaf springs both front and rear. Not only are they incredibly strong but unlike the steel springs found on older Corvettes, they don’t lose their memory, so it’s not as important to jack the wheels off the ground during winter storage.
That said, care should still be taken when it comes to the tires, to prevent them from flat spotting. One of the first things to do is check the tire pressure at each wheel.
During winter storage, a good method of preventing flat spotting is to bump up the pressure. If normal operating tire pressure is around 30 psi, then inflating the tires to 35 psi for storage will help prevent spotting. Just remember to drop the pressure back down before you start driving the car in the spring. Another good idea is adding blocks of foam under the tires, to reduce the risk of flat spotting.
If you aren’t sure what the correct tire pressure is for your car, most Corvettes should still have the factory tire pressure and loading label – on C4s it’s located on the driver’s side door jamb. If not, refer to the owner’s manual for your model and year of car.
Another good precaution is to check the transmission fluid. If it’s an automatic like this one, you need to start the engine and warm the car up before checking the fluid level.
You should not only make sure the fluid is up to the maximum level on the dipstick but also check the color. Red signifies the fluid is good – if it’s brown you should drain it and replace the transmission filter before putting the car away.
On older cars, it’s also wise to inspect the hoses for any signs of cracking or swelling, as a faulty radiator or heater hose can place additional strain on the car’s cooling system, robbing you of both performance and comfort once you get the Corvette on the road again. Plus, cleaning up sticky antifreeze as a result of blown hoses is a really messy chore – as this author knows from personal experience.
Also make sure you check the drive belts for condition and tension. Like faulty hoses, an improperly adjusted or worn drive belt can cause serious problems if left unchecked and is cheap to replace.
A good indicator of the condition of the belt can be found on the grooves on the inside. This sample belt is in good shape. If you see cracks appearing in the grooves, it’s time to replace the belt.
Another important element before putting your Corvette away for winter is to clean it. In fact, you should clean the car as if you’re getting ready for a major show, removing every last bit of dirt, grease and other residue – leaving the car unattended for several months can often cause residue to discolor the paint or damage trim. A good first step is using a quality shampoo to wash the car.
Once the Corvette has been shampooed, rinsed and dried with a detailing cloth, the next step is to wax the body to protect the paint. Because of their fiberglass bodies, traditionally more care was needed to wax Corvettes – today, modern polishes and waxes have advanced to the point that there’s a much greater degree of protection. A good quality wax, like those available from Mothers or Meguiar’s, is more than adequate.
Before you start, make sure you have a number of terry cloths available for waxing and polishing.
Adding a dab of wax to a terry cloth, slowly apply it to one section of the car at a time.
Let it glaze on the surface for a few minutes…
Before using another terry cloth to buff the paint. Some people think that adding wax and leaving it glazed on the surface during storage is a good idea. It isn’t. Come spring, that wax will have hardened to the point that it will be very difficult if not possible to remove and the car will look just awful.
On later Corvettes with black trim and moldings, make sure you remove any traces of wax or polish residue as they can cause it to turn gray, spoiling the otherwise great appearance.
Finally, use another clean terry cloth to remove any remaining traces of wax residue.
Another good idea is to clean the glass. Use specific auto glass foam or cleaner to get the best results; otherwise you’ll just smear the windows.
Use a glass cleaner towel to wipe away the excess, leaving your windows nice, clear and streak free.
Don’t forget to do the very edges of the windows too, as well as the mirrors.
Now it’s time to turn your attention to the interior. Use a slightly damp or anti-static cloth to wipe the dash clean. Do not use an “Armor” cleaner, which actually dries out the material, causing the surface to burn and sometimes, eventually crack. This stuff is best used for dressing the tires.
Once you’ve finished with the dash you can move onto the console. Anti-static cloths can help when cleaning out little crevices such as around power locks, window or mirror switches. Sometimes you can use cotton buds to get into really small areas.
Next, give the interior a good vacuum and get rid of as much dirt as you can. A good idea is to start with the mats first, as they’re often the items that absorb the most dirt and scruffy mats can detract from an otherwise nice interior. If you tend to park your car on a loose gravel driveway in the warmer months, pay special attention, as you’ll be amazed at where small gravel particles get.
Once the mats have been pulled out, vacuum every inch of the carpet, including under the seats and around the console – loose change, old french fries, you name it – can often be found hiding under the seats. Removing any old food residue is especially important as it will decompose while the car is in storage, encouraging the formation of moisture and pungent smells, which will be harder to eliminate come spring.
Don’t forget the trunk area too. On post-1982 Corvettes this is somewhat easier thanks to a lift-up glass rear window. On older cars it requires a bit more effort, usually by accessing the luggage space by folding the seats.
Another important tip is to coat the rubber seals to prevent them from drying out and sticking together, which can cause them to tear. One of the best things you can use for this is dielectric grease.
Carefully add a small amount of the grease to the weatherstripping, along the entire length.
After a few seconds, use a clean cloth to wipe away the excess. Now you’re all set.
One of the biggest potential problems that can result from extended storage is corrosion of the fuel system – and ultimately, hard starting. To prevent this, fill the gas tank right to the brim and add a fuel stabilizer. This will prevent the fuel from breaking down and going stale (which happens in as little as 60 days). If you don’t use a stabilizer, the fuel will lose its octane, the water content will increase and also a varnish type residue will build up, which can clog up fuel injectors and carburetor jets.
If the storage unit is cold and has a concrete floor, it can quickly drain the battery of energy, so the best thing is to remove it and place it somewhere warm while the car is in storage, ideally inside the house and supported on blocks of wood or carpet. Having a battery wrench makes things considerably easier. Always disconnect the negative terminal first. On C4 Corvettes, the battery can be pulled out sideways by unfastening the panel behind the front wheel.
If you aren’t going to remove the battery, then at the very least, put it on a trickle charge. Extreme cold weather tests the battery’s energy output and extended periods of sitting can drain energy which puts greater stress on the cells and plates within the battery, which shortens its operating life.
Before you finally put the car away and pull the battery for good, start the Corvette and warm up the engine for about 15 minutes to make sure the stabilizer gets absorbed into the fuel system. Then it’s time to drive into the lockup for storage.
Now that we’ve performed all of our checks and winter storage maintenance, we put the cover over the car and leave it to hibernate. Make sure you use a good quality, breathable cover that allows air to vent through it. Otherwise moisture can build up between the cover and the surface of the vehicle, causing condensation, which can eventually lead to oxidation. Another good idea is to place carpet underneath the car as it will prevent moisture from rising up from the floor, coating such vulnerable parts as the fuel and brake lines and exhaust system components.
Thanks to a few careful maintenance steps, when it comes time to pull our Corvette out again in the spring it’ll be ready for the road – looking fantastic and running perfectly!