Mechanic reveals one sign petrol and diesel owners should 'stop driving' immediately

A top car mechanic has warned petrol and diesel owners could be at risk (Image: Getty)

Top car mechanic Scotty Kilmer has warned petrol and diesel drivers could have a serious fault with a major component if they notice a vital sign. 

Smoke coming out of a car exhaust can be normal in many circumstances but sometimes could signal major issues inside the vehicle. 

Most importantly, Scotty stressed that a particular plume could indicate a problem with the vehicle's head gasket. 

The head gasket is a seal that sits between the car’s engine and is considered a crucial tool. 

Driving with head gasket problems can be dangerous with motorists likely to be affected by serious engine damage.

Exhaust smoke could indicate major issues (Image: Getty)

Speaking on his YouTube channel, Scotty claimed that motorists should “stop driving immediately” if they notice exhaust problems.

He said: “If you have black smoke and you stick your finger and your fingers black it means your engine is running too rich and isn't burning the fuel correctly.

“If it's smoking white with a little blue tint, the blue is actually metal and oil, worn piston rings. 

“When it's really cold outside all vehicles will smoke white because it's cold and the exhaust is hot. 

“But if you're driving in warmer weather and you get white smoke coming out, that generally means your head gasket is starting to go because it;’s burning coolant. 

“The white is just steam coming out of the teapot. So if your car is putting out smoke signals, now you know what the message means.”

Car insurance experts and breakdown specialists at the RAC stress that white or milky oil, loss of power or an overheating engine are signals a head gasket could be affected.

But, they also stress that “white exhaust smoke” is one of the biggest tell-tale signs of a problem. 

They commented: “When coolant flows into the combustion chamber it burns/evaporates as white smoke.”

The AA has claimed motorists can purchase a head gasket sealer as a temporary fix for issues. 

However, specialists admitted that these tools “shouldn’t be relied on as a long-term repair”

The price of replacing a head gasket can get pricey with CheckaTrade claiming that a replacement could set drivers back a staggering £700.