The Coolant System

Check the level
Check your engine coolant fluid level and make sure it's full. Over time, it's natural for coolant to become contaminated, so have your system flushed and replenished every year or 15,000 miles - or as recommended by the manufacturer.

Inspect the radiator
Overheating is often the result of poor air flow through your radiator. When your car is cool, check under the cap of your radiator for crystallized residue formed around the top or on the cap. It's a sign of restricted air flow and may lead to overheating, so have a technician replace or "flush out" your radiator.

Watch your gauge!
Your car is just as likely to overheat during stop-and-go traffic as it is during highway travel, so keep an eye on your temperature gauge (or engine light). If you gradually notice an increased reading, immediately check your coolant level; then take your car to the nearest service shop for testing.

The A/C System

Checking the A/C compressor
Refer to the manual for location and trace the entire path of the two hoses leading out of it. Look for two things:

a. Any cracks or decay in the hoses or tubes.
b. Oily substances near the joints where hoses meet parts. Even the smallest leak at a joint can shut down your entire A/C system.

Not as cool as it used to be?
If the inside of your vehicle is not as cool as it has been in the past, it may mean a switch in the system has shut down the A/C - a safety precaution engaged when your refrigerant level is too low. If this happens, have your local service technician test it.

Low air flow from the vents?
When you're not getting much air flow out of your vents with the A/C on, it does not necessarily mean you have a problem with the A/C. It may be the result of a blown fuse, which is an indicator of a problem elsewhere in the car.