Family Owned & Operated Since 1974

Len’s Auto Repair is a general automotive repair shop, specializing in computer diagnostics. We fix the problems other shops cannot. Some of the more common problems we address are drivability, electrical, brakes, suspension, rear ends, tune-ups, cooling, power windows, heating and air conditioning, state inspections, emission repair, engines, and transmissions.

In addition, we are a proud member of the Independent Tire Dealers Association, which means we can offer you the best tires at competitive prices.

Below are some of the highlights at Len’s that we are proud of, and help make us stand out from the average auto repair shop.


  • ASE Certified Master Technicians
  • ASE Blue Seal Shop
  • Domestic & Foreign Car Repair Including European, Volkswagen, and Audi
  • Member of the BBB with an A+ rating
  • Missouri State Inspection Station
  • Emission Inspection Station
  • 2 year / 24,000 mile parts & labor warranty on the majority of our repairs
  • Financing, 6 months, no interest with a $199 minimum purchase (Synchrony)
  • Started by Leonard Mertz, now owned by sons Kim, Jon, and Greg

Mat Hammett and Greg Mertz (owner) interviewed at FOX2 on August 30, 2022 about the shortage of technicians in the trade.

A Brief History of Len’s Auto


The very first Len’s Auto opened in 1974 at the intersection of Midland and Lackland. Expansion took place in 2002 when we built a new 6 bay building on the property behind the original.

8701 Lackland Road, Overland, MO


Our original Cottleville location opened in 2012 as a 6 bay shop. We quickly outgrew the space and expanded into the rest of the building making a total of 10 bays. Finally in 2022, our new building was built and we moved into 12 bay shop about a mile down the road.

5585 Highway N, Cottleville, MO


The O’Fallon location is the newest of the Len’s locations. We opened this location in late 2022 near the intersection of N Main St and Tom Ginnever. We are excited about this addition and hope to start another Len’s Auto location in the near future!

909 N Main St., O’Fallon, MO