Toro lawn mowers are well known for their reliability, and to keep them performing at their best, the oil will need to be changed at regular intervals. For a new GTS-5 mower, the first oil change will occur after 5 hours of initial run time; after that, change the oil once per year. Your GTS-5 mower may come with either a Briggs & Stratton engine or one made by Tecumseh, but both of these engines' oil is changed the same way. Standard automotive 30 weight oil can be used to fill the crankcase, and you will need no special tools to complete this task.
Start the engine and run it for about 5 minutes before changing the oil. This will heat the oil up and circulate it through the engine, catching more contaminates and making it easier to drain.
Shut the engine off and pull the spark plug boot off the spark plug itself. This will positively keep the mower from accidentally starting and running during the oil change procedure.
Place your oil pan on a level surface directly next to your lawn mower on the side with the filler cap.
Remove the oil filler cap by unscrewing it in a counterclockwise rotation. You will notice once the cap is unscrewed that it contains a dip stick that protrudes from inside of the cap.
Tip the mower up on its side so that the oil filler hole can drain into the oil pan. Hold it in position to allow all the oil to drain into the pan.
Return the mower to the ground so that it rests back on all four wheels. Wipe off any dribbling oil with your rag.
Fill the engine with fresh 30 weight oil--it will take a maximum of 20 ounces. While filling, check frequently with the cap mounted dipstick to avoid overfilling.
Once properly filled, screw back on the oil filler cap, and replace the spark plug boot.