Regularly changing the oil in your John Deere lawn mower is critical to the life of the engine. John Deere recommends changing the engine oil after the first eight hours of use, then every 50 hours. Yardener.com suggests making things easier by just doing this task every spring like clockwork, as part of a regular maintenance plan for the mower. The project mower discussed here is a John Deere 100 Series riding lawn tractor, but the process is similar for other models as well.
Turn on the mower and let it run for 10 minutes to warm up the engine oil.
Turn off the engine. Park the mower on a level surface and lock the parking brake.
Raise the hood and locate the oil drain valve. Place a drain pan beneath valve.
Turn the drain cap counterclockwise with your hand to remove it. Let the oil drain completely into the drain pan; return the drain cap.
Pull the oil dipstick out of its housing by hand. Wipe the dipstick with a shop rag.
Pour new engine oil into the housing. Add only the type and amount of oil specified in your owner's manual; never overfill. To check the oil level, reinsert the dipstick for five seconds and pull it out again. Check the dipstick; the oil level on the dipstick should be no higher than the "Full" mark.
Return the dipstick to the housing.
Turn on the mower and let it run for 10 minutes. Then turn it off again.
Check the oil level again by pulling out the dipstick, wiping it with the rag, reinserting the dipstick and then pulling it out again to view the level. Add additional oil if necessary until the level reaches or nears the "Full" mark.
Return the dipstick to the housing. Make sure that it fits snugly.
Lower the hood. Remove the drain pan and properly dispose of the used engine oil.