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5 things that go wrong with pistons (and how to prevent them)

5 things that go wrong with pistons (and how to prevent them)

Dan is an experienced motoring journalist who has more than 20 years of experience. He has been the editor of titles such as Fast Ford and Redline, and his latest project was converting an old Renault Trafic into a family campervan.

Pistons in modern engines are built to last but sometimes things can go wrong. These are the most common piston failures:

Common problems with pistons: 01 Timing belt snapped

The timing belt keeps the movement of the pistons and the valves perfectly tuned, but if it snaps they can collide and catastrophic damage can occur. It’s important to change the timing belt according to the car manufacturer’s specifications.

Common problems with pistons: 02 Worn piston rings

Piston rings eventually start to wear and the seal between the piston and cylinder is no longer air tight. As a result, oil makes its way from the crankcase past the piston and into the firing chamber. Symptoms of this are white smoke coming from the tailpipe and a drop in engine oil level.

Common problems with pistons: 03 Piston slap
If the noise doesn’t go away once the engine is up to temperature, the piston or the cylinder could be worn. A noisy piston is caused by too large a gap between the piston and the cylinder wall.

Common problems with pistons: 04 Burned piston

Only visible when the top of the engine has been removed, signs of melting, or even a hole in the top of the piston, are caused by dirty fuel injectors or the wrong type of spark plug having been installed.

Common problems with pistons: 05 Cracked piston

Causes include prolonged use of poor quality (low octane) fuel or failure of the exhaust gas recirculation (EGR) system

5 things that go wrong with pistons (and how to prevent them)

How to prevent damage to your pistons

Prevention is far better than cure when it comes to avoiding piston problems, because taking the engine apart to fix them is a labour-intensive (and therefore expensive) process.

The best way to ensure your pistons are working at peak efficiency is to make sure the rest of the car is in peak working order. So have the engine oil and filter changed at the recommended intervals - and ensure you are using the correct oil for your engine (details will be in your handbook).

Is the engine coolant in good condition? Open the radiator cap (only when the engine is cold) or look at the water in the coolant reservoir.

Is it brown and mucky? A local garage will be able to tell you if it has the correct amount of antifreeze.

Finally, check when the spark plugs (on a petrol engine) were last changed. Most will last 60,000 miles with no problem, but consult your handbook because some cars differ.