Yes it certainly can. A thief wants to get into your vehicle, start it, and drive off as quickly as possible. As soon as a thief starts to make an entry, they are exposed. A car cover takes a few minutes to remove, so the thief's exposure time is increased. With so many cars uncovered, why would a thief want to increase the risk of being caught? A cover also helps protect the contents of a vehicle. When radios and other items are out of sight they are less likely to tempt a thief.
The lock and cable accessory kit will certainly help. You should also put your name on the front of the cover. The name works better than the license number. The instruction sheet gives details on the correct way to mark the cover.
In general, always cover the front and rear bumpers as the last step. If the cover has mirror pockets, place the pockets over the mirrors first. If you have an old car you should cover the roof and windows first, and then the front and rear of the car. On some coupes and roadsters made prior to 1932, you might be unable to install the cover at all if you start with the front or the rear bumper.
The easiest way I've found is the way we picture it in our instruction sheets. Simply fold each side up onto the roof and refold it as necessary so the material ends up about 2 feet wide. Then, starting at the front of the vehicle, fold the cover towards the back in increments of about 3 feet. This way you don't drag the cover over the vehicles surface, and it's easy to reverse the process for installation.
If your vehicle is clean, it's actually the best way to dry the cover. If it's a Covercraft cover, as the temperature warms up, all the moisture will evaporate, since all of our fabrics are breathable.
Other than parking in the shade, because most of our better fabrics will protect against bird droppings and tree sap, the best thing to do is to lower your side windows about two inches. Ambient temperature builds inside enclosed spaces, and if you open the windows slightly you'll allow air to circulate, just like it circulates under the cover. Some of our fabrics offer more heat insulation than others, simply because they are multi-layered and are more effective at keeping heat away from the vehicle surface, but any cover will help reduce the vehicle temperature on a hot day.
Most fabrics are degraded by Ultra Violet Rays (UVR) from the sun. To slow down the degradation process, chemicals are added during the production of the fabric. You won't be able to see them, smell them or feel them. The chemicals are expensive so your best bet is to buy a cover from a reputable manufacturer who believes in quality. To reduce cost, one of the first things a mill will usually cut is the percentage of UVR inhibitors being used.
There is no magic number since it depends on where you live and how you use the cover. Don't be afraid to wash a car cover! Dirt particles can compromise the effectiveness of the water resistance of the fabric. Be sure to follow the washing instructions for the cover you own.
In almost every instance, a good car cover fabric has been treated with some sort of DWR (durable water repellency) treatment during it's manufacturing process. The effectiveness of such a treatment will also depend on the construction of the fabric. If you can hold the fabric up to light and see small open areas between the yarns, no treatment will increase the fabrics water resistance. Adding additional treatments will not help and aren't worth the cost.
The generic cleaning instructions noted below are intended for use with all Covercraft covers but you should refer to the instruction sheet enclosed with the car cover for any fabric specific care instructions.
Car cover fabric performance can be severely affected by dirt that builds up on and within the material. It can cause the windshield and paint to become dirty and "fogged" as well as create "wicking" where it actually helps pull water through the fabric, nullifying any water resistant properties the fabric may have had. Cleaning your cover will help to keep your vehicle clean and to increase the service life of the cover.
NEVER...Clean a car cover in a washer with a center agitator (except WeatherShield® fabric covers). NEVER...Use fabric softener. NEVER...Dry a non-woven or specialty type cover in a dryer. WeatherShield® fabric and Form-Fit™ covers can be dried in a dryer with regular heat; polycotton, cotton and flannel can be dried on low heat.
A cover may also be cleaned by turning it inside-out on the vehicle.