If you have noticed that your car's tire is partially flat every morning, it may be losing air overnight due to a slow leak. If you suspect this is true, use the following two tips to confirm your suspicions and find the cause of your tire's slow leak.
Look for a Nail or Screw
When trying to determine the cause of your tire's slow leak, the first thing you should look for is a nail, screw, or another object that has punctured the tire. Because your tire is leaking and has not gone completely flat, odds are that the culprit is still in the tire. If it were not, there would be a hole that would quickly release the air.
After filling the tire with enough air to make it round, use a flashlight to examine the tire. If the light shines off of something, this could be a nail or screw that is embedded in the rubber. If you do not find anything, move your car to expose the rest of the tire.
If you do find something in the tire, do not pull it out. Right now, the air is slowly leaking from the tire. However, if you pull out the thing causing the leak, your tire will go completely flat.
Having a tire that is completely flat would put the rims directly on the ground. The weight of your car may bend the rims, leading to the possibility that you may have to replace them along with your tires.
Examine the Tread
If your search for something puncturing the tire has given you no results, the next thing you should check is the condition of the tread itself. If your tire is old or you have driven a lot of miles on it. the rubber on the tread may become so worn that it may have become worn or ripped.
Repeating the process as described in the previous section, visually examine the tread on the tire. Also, use a flathead screwdriver to gently push along the tread marks to see if the rubber gives way. If so, this is likely what is causing the leak.
After you find the problem that is making your tire slowly leak air, you should take care of the issue before it goes completely flat or blows out on you while you are driving. Take your car to a tire shop to have them verify the leak and discuss their recommendations for either patching or replacing the tire.