Torque Shop

I have a 13-year-old car which has clocked 230,000km. While I am aware of suspension and brake overhauls that might be necessary, my concern is the engine. Years ago, my father used to speak of "top overhaul", "piston overhaul" and "de-carbonising". Should I be sending my car for any of these?

Admittedly, 230,000km is a high mileage for any car and it will not be long before some major engine work is necessary.

Tell-tale signs include increased fuel consumption, bluish-white smoke from the exhaust and high engine oil consumption.

The terms "top overhaul" and "de-carbonising" refer to refurbishing the cylinder head by essentially cleaning away any carbon.

Years ago, black soot accumulating around the cylinder head, valves and tops of pistons, like barnacles attaching to legs of a jetty, was a common problem.

These days, thanks to electronic ignition and fuel injection, plus advances in combustion chamber design and the chemistry of fuels, carbon build-up is no longer a serious problem.

Having said that, with high mileage, there is bound to be normal wear in other parts within the engine - such as piston rings and bearings.

Increased engine noise, high oil consumption and a smoky exhaust are clear signs that an engine overhaul is required. If the car has been serviced regularly with good quality lubricants, you may be lucky enough to get away with a new set of pistons and piston rings.

Often, engines which approach mileage of 300,000km or those that have been poorly maintained will require a complete engine re-build. That will be a costly endeavour.

Shreejit Changaroth

A version of this article appeared in the print edition of The Straits Times on April 20, 2019, with the headline 'Torque Shop'. Print Edition | Subscribe