Oil loses its clean, fresh look very quickly and yet may still be serviceable. The best guide to changing oil is knowing the vehicle's mileage and period of time since the last oil change. The objective of this procedure is to show you how to safely drain engine oil.
Part 1. Preparation and safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection - such as rubber gloves and barrier cream
- Respiratory equipment - such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- If the engine has been running, be careful not to burn your hand or arm on the exhaust manifold or any other hot part of the engine when reaching for the dipstick. The dipstick and the oil on it will also be hot.
- Although fresh oil is translucent, and oil that needs to be replaced looks black and dirty, it is often difficult to assess the condition of engine oil simply by its color. Oil loses its clean, fresh look very quickly and yet may still be serviceable. The best guide to changing oil is knowing the vehicle’s mileage and period of time since the last oil change.
- If the oil on the dipstick is not blackish in color but looks milky grey, this could indicate that there is some water (or coolant) being mixed into the oil. There may be a serious problem somewhere in the engine, such as leaking head gasket, and you should report this to your supervisor immediately.
Part 2: Step-by-step instruction
- Prepare the work area
Before you begin, you will need to mop up any oil spills, you must have ready a container large enough to hold all the oil from the engine you are about to drain, and have enough new oil of the correct type to refill the engine later. In some vehicles, the engine will drain more easily if the filler cap at the top of the engine has been removed, so do this before the car is lifted.
- Identify drain plug and removal tool
Always use the Service Manual to help you locate and identify components if you are not completely sure of their location. The oil drain plug is found underneath the oil pan, which holds all the oil in the engine. Some vehicles have two drain plugs, draining separate sump areas. To minimize the possibility of damage to the head of the bolt, you will need a box wrench or socket wrench to remove and replace the drain bolt. Be very careful that you do not remove the transmission drain plug by mistake.
- Remove drain bolt and inspect
When you have removed the drain bolt separate the sump plug gasket from the bolt and clean the threads. If the threads are damaged then the bolt may need to be replaced. Look for solid metal particles stuck to the bolt and report these to your supervisor. They may indicate an undiagnosed problem with the engine.
- Drain the oil
The oil will drain more efficiently from the engine if it is hot, so run the engine for a few minutes before draining. But if the oil is hot it can burn you, so be VERY careful when you remove the plug so that the oil does not spill onto your hand. If the engine is cold you will need to allow much longer for it to completely drain, or the new oil will become contaminated by residual oil still clinging to the inside surfaces of the engine.
- Safely dispose of the drained oil
If the drained oil is hot, take extra care not to spill it, especially not onto yourself. When tipping the oil from the draining container into the recycle container, again look for signs of metal particles left at the bottom of the container