Recently, my car’s engine rattles for a while when I first start it up. I notice this occurs only when the engine is cold. I do not hear the rattling at other times or when I start the car when its engine is warm. The car is seven years old and maintained regularly. It was suggested by one workshop that the engine would need an overhaul. What is your advice?

Rattling when starting a cold engine is a result of insufficient oil layer remaining on the engine parts or poor oil flow. Low oil flow will usually show up as an oil pressure warning in the car. The fact that the rattling occurs only when the engine is cold suggests the former. 

When you park overnight, the oil that is pumped around the engine drips down and settles in the sump. Quality engine lubricants are formulated so that a thin film of oil always remains between moving parts to prevent total “drying out”. Hence, there should be sufficient lubrication to prevent any noise when you start.

Usually, the source of the rattling is the timing chain that does not get enough lubrication. A similar rattling noise is not audible with timing belts, but the condition could still exist. Once the engine is running and the pump is working normally, the situation stabilises.

As you have not observed any other symptoms and your warmed-up car runs smoothly, it is highly likely that the condition is a result of poor quality lubricant. Check what engine oil was used during the last servicing. Ensure it complies with the manufacturer’s recommendations.

Going by the symptoms you described, an engine overhaul is not necessary.