Torque Shop: Metal bits in engine oil

Visible metal particles in the engine oil is a serious problem.
Visible metal particles in the engine oil is a serious problem.ST PHOTO: LIM YAOHUI

Q: My car's engine died on me one day when I was driving. It would not restart, so I had it towed to a workshop, which found tiny bits of metal in the engine oil. It sounds like a major problem. What could have caused this and what is the remedy? My car is 11 years old and has clocked 160,000km.

A: Visible metal particles in the engine oil is indeed a serious problem. You cannot flush the engine and replenish with fresh oil and hope the problem will disappear.

It is necessary to investigate the source of the metal particles.

While there will always be microscopic metal in the engine oil from normal wear and tear, there should not be larger bits which are visible to the naked eye.

The most likely sources are the connecting rod (con-rod) and crankshaft main bearings. These precision alloy components carry heavy loads while rotating at high speeds.

Having said that, 160,000km of normal usage should not cause the symptoms you have described. Hence material manufacturing defects cannot be ruled out completely.

When severe deterioration sets in, there will usually be tell-tale signs such as rattling or knocking sounds from the engine. Oil pressure will begin to drop and there will be a warning light or a message in the instrument cluster.

If you notice an oil-pressure warning at idling speed or when you accelerate, then it is likely a case of worn bearings. This calls for immediate remedial action.

Continuing to drive with these symptoms will eventually lead to engine seizure.

Unfortunately, your car's problem requires the engine to be stripped and parts replaced or components resurfaced by specialist machine shops. This can be costly.

Sometimes, the damage to bearings is so severe that the whole crankshaft has to be replaced. Also, the engine's cylinder walls may require resurfacing. If so, piston and piston rings should be replaced for all cylinders.

Regular oil changes with quality lubricants can prevent catastrophic engine failure. But this will not guard against premature component deterioration resulting from inherent material defects.

The problem with an older car is that you will never know how well it was maintained. So, if you are a recent owner, be alert to tell-tale signs and take immediate action.