How to Change Your Engine Oil and Filter Yourself

An oil and filter change is the one piece of maintenance where doing it yourself is unambiguously the right answer. The parts cost less than the labour, the process is straightforward, and the knowledge it builds about your own vehicle pays for itself the first time something else needs investigating. Done correctly and with the right specification, it is not a compromise.

This guide covers the procedure, the specification question that matters most, and the mistakes that cause immediate damage.

Why the Specification Matters More Than the Brand

Engine oil is a precisely formulated product, and the vehicle was designed around a specific specification. Getting the specification wrong does more harm than getting the brand wrong, because the specification governs viscosity, friction characteristics, and additive chemistry. A car designed for a low-viscosity oil may suffer from oil pressure problems with a thicker one, and an engine requiring specific friction characteristics for its clutch or timing system will not tolerate an arbitrary alternative.

The correct specification is in the owner's manual and on the oil filler cap, and it is worth reading both because they occasionally differ between model years. The viscosity grade, the quality standard, and any manufacturer approval requirement all apply. Do not assume a generic oil of the right viscosity is adequate, because the approval requirement exists for a reason. The point of matching the specification is covered in our guide to oil additives and specifications, where the consequences of a mismatch are set out in detail.

The filter must be the right one for the engine, and the correct oil filter costs little more than a generic one. A filter that does not seal properly, or whose bypass valve opens at the wrong pressure, produces either a leak or an oil starvation warning.

The Interval and the Preparation

Follow the manufacturer's interval, and treat it as a maximum. Shorten it substantially if the vehicle is driven mostly short trips, since fuel dilution and moisture accumulation are worse than distance alone would suggest, and lengthen it only as the manufacturer specifies for severe conditions. Changing the oil on time is worth more than changing it early, but changing it late is the failure that causes damage.

Gather what you need before starting: the correct oil in sufficient quantity, the correct filter, a new drain plug washer or crush washer, a drain pan, a correctly sized spanner, a torque wrench for the plug, and a funnel. Having the right drain plug washer is the item most often forgotten, and reusing an old one is a reliable way to leak.

Warm the engine briefly before draining, which lowers the viscosity and lets more of the old oil out of the sump. Then park on level ground, switch off, and allow it to sit for several minutes.

The Procedure

Place the drain pan under the plug before removing anything. Clean around the plug first, because debris falling into the sump when the plug comes out ends up in the engine. Remove the plug and let the oil drain for ten to fifteen minutes, which extracts considerably more than the impatient five minutes most people allow.

Inspect the drain plug and the washer as they come out. Metal debris on the plug or in the pan means internal wear and should prompt investigation rather than being discarded. A black, gritty, or burnt-smelling old oil suggests the oil was overdue or the engine is producing contamination.

While the oil drains, replace the oil filter. Unscrew the old one, wipe the mounting face clean, check the rubber gasket on the new filter, and apply a thin film of clean oil to the gasket before fitting. Hand-tighten the filter until the gasket contacts, then tighten by the specified fraction of a turn. Overtightening cracks the canister, which is a much more expensive problem than a slightly loose filter.

Fit the new drain plug with a new washer and tighten it to the specified torque with a torque wrench. This is the one fastener on the car where over-tightening is a real and common mistake, and aluminium threads strip easily, so if the plug has been replaced with a steel one before, the correct torque is lower than the original.

Fill the sump with slightly less than the stated capacity, because not all the oil will remain in the sump; a significant volume stays in the filter, the head, and the passages. Add it in stages, checking the level between additions rather than all at once, and never overfill. Overfilling is a genuine problem: the excess is picked up by the crankcase ventilation and carried into the intake, causing foaming, reduced lubrication pressure, and a running fault.

Run the engine for two to three minutes, then stop and check the level. Top up as necessary, run again, and check once more. Some engines will consume a measurable amount of oil over the first few thousand kilometres after a service, so a top-up shortly after the change is not unusual. Clean any spillage immediately, since oil on a drive is both a slip hazard and a persistent smell source.

What Not to Do

Do not overfill, which is the most consequential and most common error. Do not fit a filter without oil in it first if the engine will run immediately, because a dry filter restricts flow at the moment of start. Do not use a drain plug without a washer or sealant as specified. Do not mix oil types unless the specification explicitly permits it, since some are not compatible and the result is sludge. Do not skip the interval because the oil looks clean, because it oxidises and loses its properties before it looks bad.

On a diesel, do not add oil before asking, because a diesel that is short of oil may be pumping air into the system rather than burning, and the diagnosis is quite different.

Record It

Record the date, the distance, and the oil specification at each change. That record establishes whether the engine is consuming oil, whether the interval is right for how the vehicle is actually used, and it supports any warranty claim, since service history is a factor in whether a manufacturer honours one. The distinction between a warranty and an insurance claim is covered in our guide to the difference between the two.

Checking the level between services is the other half of the job, and an engine that is losing oil between changes has a fault that is worth finding rather than topping up. The rest of the routine belongs in a standard vehicle maintenance schedule. If this guide was helpful, you may also want to read how to fit a car battery yourself for another job that is genuinely straightforward and is often left to a workshop unnecessarily.