Oil- and oil-filter change

Take a 5 km drive to warm up your engine (warm oil drains out better than cold oil). Don’t go too far, as you don’t want it so hot that you risk burning yourself. Park your vehicle on a level spot and put the ignition keys somewhere far away, and safe. ( You really don’t want to absentmindedly start your engine until you have finished the job!)

Place several sheets of newspaper under the engine to protect the floor, then position your oil drain container under the engine and below the sump plug. (If these are completely foreign terms to you, maybe stop now and make an appointment at your nearest trustworthy service centre).

On many late-model vehicles, there is a large cover beneath the engine to improve the aerodynamics. This will have to be removed before you can access the sump plug. Be sure to save all the small bolts or screws to re-fit the cover afterwards.

Loosen the sump plug ( but do not remove it just yet), position your container to catch the imminent flow of warm engine oil, then turn the sump plug out until you can grab it just before it falls into the tray – this will be followed by a cascade of warm engine oil. Keep your hands clear! If the plug falls into the tray, you can retrieve it later.

Wait five minutes while all the oil drains out of your engine. If you are a purist, you will now proceed to jack up various wheels to do maintenance work on the brakes and wheels ( but we’ll discuss that another time). The changing angles of the car ensure that you drain every last dreg of the old, grimy oil. Now remove the oil filter. This is either a cylindrical spin-off cartridge roughly 100 mm in diameter and between 100 mm and 150 mm long, which is screwed on to a housing against the engine block, or it may be a housing with a screw-on cover with the actual filter element inside. (Some engine designers, it appears, take great d delight in making the oil f filter as inaccessible as po possible, meaning you need rubber wrists and superhuman strength to get to it.) Clean off all dirt where the filter or cover me meets the housing, then unsc unscrew the filter by turning it anti- c clockwise away from the mounting poi point. With the spin- off cartridge type, you may find that it’s so tight you can’t turn it. There are specialised spanners available from auto-spares suppliers which make this a bit easier. Some are okay, and some, well, some are junk; unfortunately, you don’t generally get

to make this distinction until you use them. I just use a hammer, and I punch a large screwdriver right through the old filter, then pull on the screwdriver to loosen it (you’ll definitely require newspaper on the floor in this instance, , as this is the messy method).

Discard the old cartridge filter or, in the case of those with a cover, remove the filter element and discard (safely and sensibly, as mentioned in the ‘ Oil

Disposal’ sidebar). Smear clean oil on to the rubber seal on the new cartridge filter and screw it into place, as tight as you can make it by hand. (Purists fill the filter with new oil first, thus reducing the time the engine will be operating without lubrication). For the other type, insert the filter into the housing and then carefully replace the cover. Pour in some clean oil if you wish.

Replace and tighten the sump plug. Don’t forget this point. Really.

Fill the engine with the correct quantity and grade of new oil – check your service manual for these specs. You do this by pouring in the required volume through the filler cap located on top of the engine tappet cover. (‘ Tappet cover?’ you say… Okay, off to your service centre.)

Replace the filler cap once you’ve poured in the required amount of oil.

Now, if you can remember where you put your keys, start the engine and run it for about two minutes. Switch off and check at the sump plug and oil filter for leaks. Tighten if necessary. Wait another two minutes, then check the oil level using the dipstick. Top up to no higher than the upper mark on the dipstick, and always wait for the additional oil to settle down to the sump before you re- check the dipstick.

Never, ever overfill, as this can cause engine damage.

Air-filter change

The air filter sits inside a big black housing to one- or other side of the engine. Sometimes it’s even right on top of the engine. As most engines these days use a pleated-paper air filter, this is what I will talk about.

The housing will have a cover or lid l of some sort, held on by means of toggle clamps. Clean all loose dirt from the housing, then loosen the clamps. c Depending on the layout, you may also have to loosen the circular clips around the f lexible rubber duct connecting the filter housing h to the intake manifold.

Watch out for any little pipes connected c to the housing or inlet manifold. If you have to remove any, take careful note of which ones o go where.

Take off the cover and remove the dirty filter. Don’t let any dirt fall into the ‘clean’ area of the housing, or into the intake manifold. Wipe (or vacuum) any dirt from the housing. Fit the new filter, then close up and secure the cover and all clips, hoses and fasteners. Job done.

Fuel-filter change (petrol) Safety first, always! Petrol is highly flammable, so do not smoke or use any naked flames while you carry out this task. Switch off the engine and remove your keys from the ignition.

Look for the housing or component that looks like the new fuel filter you bought for your model of car. On many vehicles, this might be underneath, somewhere around the region of the rear axle.

Quite simply, clean off all external dirt, undo any hose- clamps or cover screws and replace the filter. If doing in-line filters, ensure that you get the flow direction right, usually indicated by an arrow on the housing.

Replace all clamps or screws, and then start your car and check for any fuel leaks.

Fuel-filter change (diesel) Switch off the engine and remove your keys from the ignition.

Because the injector pump operates at very small clearances and the fuel’s more viscous, diesel filters are bigger and more sophisticated than their petrol counterparts. You may even have two of them in series – one to remove moisture and one for dirt.

Thoroughly clean off the housings before you begin. Sometimes the filter bowls screw off just like the spin- off cartridge- type oil filter mentioned earlier, whereas sometimes they are secured by a centre bolt, or sit under a cover. Just analyse the task and work at it logically. If you are at all unsure, get professional advice or assistance. Fit the new filter or filters. Importantly, you now have to bleed the air out of the filters, otherwise the injector pump will suffer cavitation and not deliver fuel to the injectors. The user manual may indicate where to find the bleed screw. If not, look for a prominent screw with a drain port adjacent to it somewhere on the filter housing. It may even have a convenient short length of hose attached to it. Run the hose into an empty jam tin, if there is space, or connect an extension to it and down to a tin on the floor.

Loosen the bleed screw one full turn. Switch on the ignition, but do not start the engine. Somewhere near the fuel tank, you will hear the fuel delivery pump running. Wait at the bleed screw until fuel flows cleanly from the hose, then close the bleed screw. Remove the jam tin and dispose of the fuel safely.

On later-model engines, you merely have to depress a button on the top of the filter housing with the ignition on to purge any air back to the fuel tank.

Now start the engine. If it does not start after a couple of tries, repeat the bleeding exercise.

Check for any fuel leaks.

Changing the spark plugs The most important thing here is to not mix up where all the spark-plug leads go, especially on a six- or eighttcylinder engine. Identify them by y tagging each with a piece of masking ing tape, then pull the rubber caps off the spark plugs. Be careful not to pull on the lead as it can break out of the end- cap p quite easily, meaning you’ll l need to buy a replacement. t.

If your engine is dirty and there is grime around the bases of the spark plugs, use a small paintbrush tbrush to clean this away as best you can. A household vacuum cleaner with a small nozzle attachment works very well for this too.

Now, using a standard plug spanner, remove all the spark plugs and place them on your workbench, oriented as they are in the engine, and examine them. They should all be a brownish colour and oil-free.

If they are black and sooty, your engine is running too rich and you are wasting fuel. If they are all a very light grey, your engine may be running too lean. (These observations are especially applicable to the older carburettoraspirated engines.) If they are black and oily, either your piston rings or your valve-stem seals are worn. These will require specialist attention and are beyond the scope of this article.

If only one or two are black and oily, then it’s likely that there is a broken piston ring on that cylinder, and because you kept them in order, you now know which cylinder it is.

Now that we’ve dispensed with this engine- diagnosis opportunity, set the electrode gap on all your new spark plugs to the measurement specified in your user manual. The new gap is usually just a little too big and you need to gently tap the electrode to close it until your feeler gauge just drags through the gap. If you overdo it and need to open the gap again, use your long-nose pliers and bend the electrode open from its root. Never use a feeler gauge as a lever for this task, as you will stress the enamel surrounding the central electrode, causing it to crack.

Fit the new spark plugs and tighten only moderately. Be very careful not to cross-thread them – this is a very expensive mistake to make, as it may result in you having to have the whole cylinder head removed.

Replace the spark-plug leads in the right order, and you’re ready to roll.