Tools for Inspecting Your Fleet

In order to perform a regular thorough inspection of your fleet of vehicles, there are only a few items that you will need to have handy. These tools, which are readily available online or at your local auto parts store, provide basic measurements for your visual inspection and will assist in giving detailed information to your maintenance provider, saving you time and money.

Adjustable Mirror

The mirror helps you to check the bottom side of the main hoses from the radiator for leaks, inspect the thermostat housing for leaks and look for any lubricant and other fluid leaks in hard to see areas. It also saves you from having to crawl up under the vehicle.

Coolant Tester

The simple 5 ball float coolant tester pictured above is a very inexpensive and used to evaluate the quality of your radiator fluid. Ideally, when sampling the fluid, you want all 5 balls to float which indicates a -40 degree F freeze protection. The lower the freeze protection indicated also translates to a higher boiling temperature protecting from overheat situations. Change the coolant at the recommended schedule. For most car and light trucks this is 5 years or 100,000 miles for extended use coolants. Be sure to let the system cool before testing, and ideally test at the radiator fill rather than the overflow tank.

Pressure Gauge

Use the tire gauge to make sure your tires are set to the recommended pressures. A sticker on the lower part of the driver door frame will list the manufacturer specs. A pressure sealing cap should be on each tire inflation valve to insure no leaks from the stem end. Keep extras on hand just in case.

Tread Depth Gauge

The tread gauge gives you a clear measure of remaining tread depth and remaining life for your tires. Each tire has raised “bumps” inside the deep tread groves which typically indicate 2/32” of tread remaining, the minimum safe depth. Ideally you do not want to let your tires wear to this point. To measure, use a tread groove about mid-way from center line of the tire to the edge. Place the gauge over the groove and lightly press until it bottoms out and read the number on the gauge.

Serpentine Belt Groove Wear Gauge

The last tool in the photo is the serpentine belt groove wear gauge. Belts manufactured after the year 2000 do not crack and show visible problems like older belts. This may lead to leaving the belt on too long causing slippage of the belt and possibly leading to overheating, A/C malfunctions and battery charge issues. To use the belt wear gauge, lay the long thin part of the gauge in any of the groves in the serpentine belt. Then rub your finger across the grooves from one side to the other. If you can feel the gauge above the grooves your belt is OK. If you do not feel the gauge above the grooves, it is time to replace the belt. The photo below shows a belt that is worn out. You can see the depth of the grooves and “squaring” of the groove.

Manufacturers also design the belt tensioner with an indicator. As the belt wears the “wedge” designed on the back of the tensioner rides lower in relation to a gauge. This does not show actual wear of the belt but is useful.

Post Contributor: Jim Russell, Fleet Management Consultant

About the Author

Lori Sullivan
Marketing Director

Lori is the Director of Marketing at Fleetio and a seasoned B2B marketing and automotive advertising expert. When she's not nerding out on marketing metrics or podcasts, she is binge-watching Netflix crime dramas with her dog, Fitzgerald.

Ready to get started?

Join thousands of fleets running on Fleetio

Questions? Call us at 1-800-975-5304 or email