Craftsman Craftsman M110 140cc 21" Push Gas Lawn Mower MECH-OIL-LEAK Error Fix: Engine Oil Leak or Excessive Oil Consumption

Error code MECH-OIL-LEAK on the Craftsman Craftsman M110 140cc 21" Push Gas Lawn Mower means: Engine Oil Leak or Excessive Oil Consumption. Oil is visible on or under the mower engine, or the oil level drops noticeably between uses. Common leak locations and causes: (1) Drain plug loose or bad washer — check the oil drain plug at the bottom of the engine for tightness. Replace the sealing washer if it is crushed or damaged. (2) Oil overfill — if the oil level is above the FULL mark on the dipstick, excess oil can blow out through the breather tube or seep from gaskets under pressure. Drain to the correct level. (3) Tipped mower — if the mower was tilted with the air filter side DOWN for blade inspection or cleaning, oil runs into the air filter housing and cylinder. Always tilt the mower with the air filter side UP (carburetor side up). Clean the air filter and let the mower run for a few minutes to burn off residual oil (expect white smoke temporarily). (4) Valve cover gasket — oil seeps from around the rocker cover. Replace the gasket. (5) Worn piston rings — the engine consumes oil internally, producing blue/white smoke from the exhaust. This indicates significant engine wear. For most push mowers, ring replacement is not cost-effective. (6) Crankcase seal — oil leaks from the crankshaft seal at either end of the engine. Seal replacement requires partial engine disassembly.

The most successful fix is "Replace Valve Cover Gasket to Stop Oil Seepage" (medium difficulty, ~45 minutes). Estimated DIY cost: $15-$25. HomeMD has 2 community-ranked fixes for this error.

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Yes — the top-ranked community fix ("Replace Valve Cover Gasket to Stop Oil Seepage") is rated medium difficulty and takes about 45 minutes. Tools needed: 10mm socket wrench, Ratchet, Gasket scraper, Torque wrench.

DIY cost: $15-$25. Professional repair typically costs $120-$180. Many homeowners save money by trying the top-ranked community fix first.

The Craftsman Craftsman M110 140cc 21" Push Gas Lawn Mower has 8 other known error codes, including: MECH-FUEL-LEAK (Fuel Leaking from Mower — Fire Hazard), MECH-PULL-CORD (Pull Cord Breaks, Sticks, or Will Not Retract), MECH-RUNS-ROUGH (Engine Surges, Sputters, or Runs Rough), MECH-SELF-PROPEL (Self-Propel Drive Not Working or Weak), MECH-SMOKE (Engine Emits Excessive Smoke (White, Blue, or Black)), and 3 more.

Error code MECH-OIL-LEAK also appears on 5 other Craftsman models: Craftsman R105 30" 10.5 HP Gear-Drive Rear Engine Riding Mower, Craftsman T110 42" 17.5 HP Briggs & Stratton Single-Cylinder Riding Lawn Tractor, M270 21 in 159 cc 3-in-1 Self-Propelled Gas Push Mower, T210 46" Turn Tight, Z560 54 in 24 HP V-Twin Zero-Turn Riding Mower. The fix may vary by model, so check each model's specific page for tailored repair steps.