Motorists making short, low-speed journeys could be unknowingly damaging their car engines, according to car repair experts.

While many drivers believe cautious driving at lower speeds is better for their vehicles, mechanics warn that this habit could lead to harmful carbon build-up.

This issue, known among mechanics as "Black Death", occurs when carbon deposits form in the engine's internal components during regular, slow driving.

One simple change to driving habits could prevent this expensive damage and even improve vehicle performance.

Drivers should take action if they are having engine issues

Carbon deposits form when unburned fuel residue accumulates during low-speed urban driving.

A spokesperson for Bumber said: "Modern engines are designed to run efficiently at a wide range of speeds. If you're only ever pottering around town at 30mph or less, you could actually be encouraging harmful carbon deposits to form in the engine's internal components."

These deposits can clog valves and piston rings over time, which results in reduced engine performance and increased fuel consumption.

In severe cases, carbon build-up may cause complete engine failure, potentially requiring an expensive engine replacement costing thousands of pounds.

Experts say the solution to this problem is surprisingly simple, and includes taking their car for regular higher-speed drives.

The expert added: "When you drive on the motorway or dual carriageway at higher revs, the fuel moves through the system more forcefully. Petrol acts as a mild solvent at these speeds, helping to clean the inside of your engine while keeping it properly lubricated."

This natural cleaning process helps prevent the build-up of harmful deposits. Regular motorway driving can effectively maintain engine health and avoid costly repairs down the line.

Motorists should also watch for warning signs of engine problems caused by short journeys. Bumper warns drivers to check under their oil cap for white foam, which indicates water condensation mixing with oil.

The spokesperson said: "If you spot a white, frothy residue under your oil cap, that's likely a sign of water condensation mixing with oil, which can happen if the engine doesn't reach high enough temperatures to evaporate moisture."

A longer drive at motorway speeds for about an hour can solve this issue, as it can raise the engine temperature sufficiently to burn off excess water and restore proper oil consistency.

While regular servicing remains essential for car maintenance, driving habits play a crucial role in preventing engine problems.

The expert said taking cars for occasional higher-speed drives within legal limits can significantly reduce the risk of carbon build-up.

Experts called on motorists to check their engines regularly

The Bumper spokesperson said: "Taking your car for a proper drive once in a while doesn't just benefit performance - it could help you avoid hidden engine problems, save on fuel, and reduce the risk of expensive repair bills down the line."