Engines: Engine Lubrication: Lubrication procedures
Checking engine oil
 
Make sure the vehicle is on a level surface and the engine is off before taking a reading. If you don't, you'll get inaccurate readings.
 
Draining engine oil
 
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.
 
Replacing an oil filter
 
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.
 
Refilling engine oil 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.