How much exhaust smoke is normal

Or is it thick and black? Does it evaporate as soon as it's in the air? Or does the smoke linger and come with an acrid smell? If it's black smoke, then does it leave soot on the road under the exhaust tip when the car is stationary? The main causes of smoke from an exhaust can vary depending on your car and its condition. If your car is well maintained and serviced regularly, then any visible emissions from your exhaust are unlikely to be anything of concern, but it is well worth checking anyway.

The real issue is with cars that have been poorly maintained, as smoke from the exhaust could be a clear sign of neglect. This can be a useful clue when buying a used car , because if the service history is incomplete, a smoking exhaust can be a tell-tale sign of underlying problems. The smoke you see can be caused by different things, depending on whether your car has a petrol or diesel engine.

If you drive a hybrid , you too could see your exhaust putting out something that you might not be prepared for. We've separated the different kinds of smoke you'll come across to help you quickly identify what problem causes which smoke.

The summaries for each exhaust smoke type are directly below but you can scroll down the page for a full explanation….

Excessive amounts of white smoke could indicate head gasket failure. There are a number of potential causes, with the more severe being worn valve seals, piston rings or turbochargers.

A longer drive - ideally on a motorway to enable higher speed and revs - should give the filter a chance to clean itself, resolving the problem. The most common form of smoke from an exhaust isn't actually smoke at all. When a cold engine is started, it soon begins to heat up, and a byproduct of this is water vapour.

This creates condensation within the exhaust system, which then turns into steam as temperatures rise within the engine. Once a car has warmed up, this steam soon evaporates. However, problems can occur if you only use a car for short journeys, meaning that the exhaust system doesn't get completely warm all the way to the exhaust tip. If condensation forms in the system and doesn't clear, it can corrode the inside of the bare steel of the exhaust, leading to rust that could develop into exhaust leaks and blowing from the system - where exhaust gases leak out.

This could lead to an MOT failure due to incorrect readings on the emissions test. Because hybrid cars especially plug-ins don't always fire up the engine straight away, this can delay you from seeing steam coming from your exhaust.

Depending on how much battery range you drive on, you could see steam from your exhaust well into your journey. But this again is nothing to worry about, it's just a delayed reaction to the same heating process mentioned above.

If the white smoke coming from the exhaust is thicker and doesn't stop, it is still steam, but also an indicator of a more severe issue that will be caused by your car's coolant leaking into the engine. Find your nearest Firestone Complete Auto Care and bring your vehicle in for a courtesy inspection today, and if needed, an important repair!

Blog Categories Blog Home. Car Exhaust Smoke Colors Light or thin white exhaust smoke Diagnosis: Normal Light or thin white exhaust smoke is typically water vapor.

Black exhaust smoke Diagnosis: Not normal Black exhaust smoke can appear when the vehicle is burning too much fuel.

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Find a Different Location Find a Store. This will definitely lead to a need for major auto repair and perhaps even an engine rebuild or replacement. It is important to pay attention to the signs of trouble that your car gives you, in this case by using smoke signals. If your car is suffering from large clouds of exhaust it more than likely needs some sort of engine diagnostics. Our team of skilled mechanics will be able to quickly diagnose the problem and have you on your way in no time!

As a full service auto repair and transmission service specialist you can count on us to take great care of your import or domestic vehicle.

Call West Transmissions at to schedule an appointment for affordable auto repair in Gretna today! What is Leaking from My Car? What Causes Transmission Trouble?