Why is Blue Smoke Coming From My Exhaust?

Blue Smoke From Exhaust When Accelerating

When blue smoke is emitted from a car’s exhaust pipe, this usually indicates that a leak in the engine’s valve seals is allowing oil to leak into the combustion chamber where it is being burned along with the fuel. This may be due to natural deterioration or a faulty part.

The smoke from a car’s exhaust pipe can be one of several colours, including grey, white and black, depending on specific problems the engine or other parts of the car’s internal machinery might be experiencing. If the smoke expelled is anything other than the common thin, grey exhaust fume smoke, then it’s a reasonable assumption that there is a problem worth investigating. It’s important that you recognise this possibility as quickly as possible so the issue can be resolved before it becomes serious.

Leaking Valve Seal

A valve seal sits within the cylinder head and regulates the amount of oil that passes through the engine – enough needs to get through to lubricate the engine, but if too much passes through it will burn in the combustion chamber, which is bad for the environment and for the vehicle’s emission system. It will also cost you more money in topping up the oil as levels decrease faster than they normally would.

When a valve seal develops a leak (which is usually due to the car’s age or consistently high usage), you should take it to a mechanic so they can replace the problematic seal. As a car can have anywhere between 8 and 32 valve seals, a professional will be able to ascertain which one is causing the problem and needs replacing.

Oil Coming Out of Exhaust

In addition to blue smoke being emitted from the car’s exhaust, you should also monitor your oil levels and have an idea of what the decrease rate should be so you can tell if the levels suddenly start declining at a faster rate. Whether you notice this before the blue smoke could have an impact on whether the seal can be repaired on completely replaced. As with most mechanical problems, the earlier you can catch it, the better.