Loss of oil may be the result of a leak around the oil-pan drain plug. A pool of oil found on the garage floor tips you off to this possibility.
The leak can occur when someone changing oil disregards the importance of the washer that was placed on the drain plug by the manufacturer.
This washer is made of a soft material, such as copper or aluminum, so that it will crush when the drain plug is tightened. The purpose is to prevent overtightening of the drain plug, which can damage the oil pan and cause a leak. To prevent this, the washer should be replaced whenever the drain plug is removed to change oil in the engine. Washers are available from dealerships that sell your make of vehicle and from auto parts stores.
If this advice comes too late and your oil pan currently is leaking, make the repair as follows:
- Drive the vehicle at least 10 miles to heat the oil so that it will flow more readily from the engine.
- Park the vehicle on level ground. Place an automatic transmission in Park or a manual transmission in gear. Engage the parking brake.
- Wear a pair of heavy work gloves to prevent burns. Place a large basin under the oil pan and turn the drain plug with a wrench. When the plug is loose enough, unscrew it by hand.
- Allow the oil ample time to drain fully. Drainage is complete when not one drop of oil falls from the drain hole in one minute.
- Buy a specially made oversize drain plug from an auto parts dealer. The one you want is designed to rethread damaged threads in the oil pan, allowing the new plug to seat properly and seal the leak. Start the plug into the drain hole by hand, and then use a wrench to seat the plug. Stop turning as soon as the plug is secure.
- Pour fresh oil into the engine through the oil filler tube in the engine compartment. Consult your owner’s manual or a dealership that sells your make of vehicle to find out how much oil to add. Most engines hold five quarts of oil.
- Start the engine and let it run for a few minutes. Then, turn it off and check to see whether oil leaks from around the plug. If there is a drip, tighten the drain plug a bit and recheck. If there is no leak, check the oil level using the dipstick and add as much oil as necessary to bring the level to or nearly to the FULL mark on the dipstick.
