Common Car Engine Problems and their Causes

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Your car is a complex piece of machinery and the engine is the heart of the machine. Engine problems can have a variety of causes from mechanical to electrical to lubrication. Recognising common engine problems and understanding their causes can help you to ensure your vehicle has a long and happy life, while saving you money on costly repairs.

Even a minor problem, like being low on oil, can develop into a seriously expensive engine replacement. So before you go looking at replacement motors for sale, take the time to get to know some of the common engine problems and their causes.

Engine Overheating

If you notice the temperature gauge rising or steam or smoke coming from under the bonnet, then you’ve got a problem and you should stop the car immediately. An overheating engine can cause serious and sometimes irreparable damage to your engine.

Some of the common causes of engine overheating include:

  • Low or leaking coolant
  • Cooling fan not working
  • Faulty radiator
  • Damaged radiator hoses (split, kinked or perished)
  • Clogged or worn out air filter
  • Blown or cracked head gasket

If you need to top up the coolant, that will be enough to get the car going again. However, since the radiator is a closed system, lack of coolant usually means there is a leak in the system. You should get your radiator checked as soon as possible.

While you should not drive your car long distances when it is overheating, you can travel short distances in an emergency, like getting to the mechanic.

To minimise damage to your engine, turn your air conditioner off. Running the air conditioner puts pressure on your engine, so switching it off can help.

You can then also run the heater. As the heater uses its own fan, this can draw heat away from the engine and into the car. Open the windows though so you don’t overheat.

If you have concerns about causing additional damage to the engine, see if a mechanic can visit you or transport your car to their workshop.

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Engine doesn’t Start

There are lots of small reasons why your car might not start. These include:

  • Faulty battery — listen for a click when you turn the key in the ignition
  • Corroded or disconnected battery terminals — older batteries accumulate rust and salt particles and should be cleaned regularly
  • Failing fuel pump — you might notice other problems like increased engine temperature, sudden losses of engine power and the engine spluttering
  • Blocked or faulty fuel filter — your engine may sound rough when it idles, or your engine cuts out or dies mid-drive
  • Broken or faulty ignition switch — this can also cause your car to stall or stop while driving
  • Faulty starter motor — you might also hear grinding noises or smell smoke when attempting to start the car
  • Faulty or damaged alternator — look out for battery issues, like lights dimming when you try starting the car

If you suspect battery issues, try jumpstarting your battery (if it’s dead) and getting it tested. If the battery is dirty, clean and grease the terminals for a better connection.

For any other problems, you need to get the individual components, like the fuel pump or starter motor, tested by a registered mechanic. They may need to repair or replace the part. Keep in mind that for starter motors, it’s often cheaper in the long run to replace rather than repair them.

Engine is Smoking

Often the colour of the smoke will be a clue to what is causing the problem.

  • Blue smoke usually means an oil leak in combustion chamber
  • Grey smoke can mean an oil or transmission fluid leak in combustion chamber
  • White smoke means burning off built up condensation or coolant burning, suggesting a cracked engine block or blown head gasket
  • Black smoke means clogged air filter, or faulty fuel injectors or fuel pressure regulator

Obviously smoke is never a good sign. If you’re seeing any smoke coming from the engine or the exhaust, you should consult your mechanic as quickly as possible.

Engine making Odd Noises

As with smoke, you can diagnose your car’s engine problems by the sounds it makes.

  • Squealing and screeching is usually an issue with the drive belt, but if the engine temperature is also rising, this can indicate water pump has failed
  • Knocking means bad fuel, build-up of carbon deposits or worn-out spark plugs
  • Clicking can mean low oil or issues with valve train
  • Whining means power steering issues, like low fluid, or worn wheel bearings
  • Rattling, if coming from under the bonnet, could be the idler pulley, air conditioning compressor clutch or belt tensioner

If you hear rattling from under the bonnet, have your car checked by a mechanic immediately. Otherwise, monitor the noises, noting how often they occur and when they occur, like when you start the car or at other times when driving.

If the noise is persistent and continues for more than a few days, take your car to a mechanic.

Engine problems can often be simply fixed by repairing or replacing a small part. However, this doesn’t mean they should be overlooked. Taking good care of your engine is part of regularly maintaining your car. Remember, minor repairs and maintenance can save you from major more costly repairs down the road.