WITH A WARM ENGINE
The other filter type is this traditional element design, which has made a comeback in the last 15 years. It consists of a top-threaded housing (typically made from plastic) containing a replaceable filter cartridge. Unscrew the element top partially, allow the oil to drain into the sump, then lift the unit away from the engine block. Replacement element filter kits will include a seal for the top of the housing, which must be replaced. Prise it away with a screwdriver, as pictured, discard it and fit the new item. The old oil-soaked filter can be pulled from the housing, so that the new filter can click into place. Prior to refitting the housing, lubricate the seal and thread with clean engine oil, before screwing it into place by hand to start, then use a socket to tighten it to the specified torque. Avoid applying excessive pressure to the plastic housing and do not use an open-ended spanner, or mole grips, in lieu of a socket.
If fitted, add a new crushable copper/ aluminium washer to the sump drain plug – reusing the old one is likely to result in a messy oil leak. Screw the plug into place by hand and tighten it to the specified torque. Be wary of overtightening. This can strip the delicate aluminium threads in the sump, which are common to most modern cars.
Remove the oil cap and wipe its underside. Should a rubber seal be fitted, ensure that it is not cracked. Pour in the correct quantity of fresh lubricant via the oil filler, taking care not to spill any oil over the engine. Consult your workshop manual for the correct capacity, including that of the oil filter.
Start the engine and note that the dashboard’s oil pressure lamp should extinguish soon afterwards. Allow the engine to run for several minutes, prior to switching it off and checking the level on the oil dipstick. Top-up if required, using the dipstick after each fill to check the level of oil. Neither underfill, nor overfill. Some engines don’t have a dipstick, in which case consult your handbook.
Manual gearbox oil levels should not drop, unless there is an obvious leak. Check your workshop manual, or locate the combined filler/level plug. Should you undo the wrong bolt, you might dismantle parts within the gearbox. Not all cars are fitted with level plugs, in which case drain the fluid and refill with the specified quantity. If no dribble of fluid comes out (presuming the engine is cold and a filler/level plug is fitted), top-up the oil with a squeezy bottle, but heed advice about obtaining the correct specification lubricant. When you notice fluid trickle out of the hole, refit the plug with a new copper washer and tighten it to the torque specified in the manual. Many manufacturers state that their transmissions are ‘sealed for life’, but it’s worthwhile changing the oil every 50,000 miles regardless, ensuring that you use the correct oil. A drain plug might be provided (as pictured) for the combined manual gearbox and differential unit. Conventional (ie, neither single nor twin-clutch) automatic transmission fluid level checks are dependent on the oil’s temperature – consult your handbook on how to check the level and ensure that the fluid is neither brown, nor black. Many transmissions also benefit from fluid changes, despite most being advertised as ‘sealed for life’, but it's quite an involved process.