Whether your vehicle runs on diesel or gasoline, it will produce exhaust smoke during regular operation. However, certain colors of exhaust can signal that you need a truck or car repair. Below is more information on what colors to watch for so you know when to contact an auto shop.

Common Exhaust Colors With Gasoline Engines

Black or Gray

Smoke with a black or gray tint indicates that the engine isn’t able to properly use the fuel, resulting in a drop in efficiency and operation.

An old or dirty air filter can cause this, as it limits the airflow required for combustion. Oil leaks can also cause this, as can faulty fuel injectors that don’t send enough gas to the combustion chamber of the engine.

White

If you’re seeing thin white smoke coming from the tailpipe, it’s due to moisture being burnt in the exhaust system, which is normal.

Thick white clouds, however, may indicate a broken head gasket, block, or cylinder head, which causes coolant to leak into the combustion chamber. Without prompt car repair, the vehicle can overheat. 

Blue

If your smoke has a bluish tint to it, it’s because oil is being burnt somewhere in the engine. Several issues can cause this, including worn valves and cylinders or an oil leak close to the combustion components. 

Common Exhaust Colors With Diesel Engines

Black or Gray

These colors also indicate improper combustion of fuel, which may be caused by oil leaks, clogged air filters, or failing fuel injectors.

In diesel engines exclusively, they can also be caused by improper combustion timing, using the wrong fuel, or an overheating engine.

White

White smoke is never normal in a diesel-powered vehicle, and it means that there isn’t enough heat in the combustion chamber.

Common causes include overheating, clogged fuel filters, failing or dirty injectors, or diesel that’s been contaminated by moisture or water.

Blue

Like with gasoline engines, blue smoke can be caused by oil being burnt due to worn parts and oil leaks.

However, with diesel engines, this could also indicate that you’re using the wrong oil or too much of it, which causes the liquid to come into contact with the bores. A faulty injector or lift pump can also cause this issue, as it allows diesel to mix with the oil.

 

If you need truck or car repair, turn to the professionals at Craig’s Towing & Repair in La Crosse, WI. They have over 25 years of experience providing advanced diagnostics for brake, engine, transmission, alternator, and radiator issues. They accept walk-ins for repairs and have a tow truck if your vehicle isn’t operable. Learn more about their auto shop online, and call (608) 784-1638 if you need to schedule a tow truck or repair.