Is your car’s exhaust smoking badly? Not sure what the cause is?

A small amount of white smoke is normal for any vehicle, especially on cold mornings – engines will naturally produce white smoke which is just water vapor (steam). But if your car is producing a lot of white smoke or has black / blue smoke then this can be a sign that something is going wrong.

White Smoke

White exhaust smoke is water vapor (steam) and comes from the heat of the engine boiling any water it comes into contact with… On cold, damp mornings water can be present in your exhaust (condensation) which is naturally burnt away and turned into white smoke. This can last for quite a few miles but should disappear once the engine has got up to normal temperature.

If you car is producing a LOT of white smoke or is producing white smoke all the time then this is a sign that water is getting into the engine and water and engines do not mix well!

Possible causes of water getting into the engine include:

• Worn Head Gasket
• Cracked Engine Block
• Damaged Cylinder Head

Black Smoke

If your car emits a little black smoke at start-up, but it clears up as the engine warms to operating temperature, don’t worry – that’s normal for some cars. If it continues after the car warms up, there’s cause for concern. Black smoke is a sign that the engine is over-fueling (it is burning more fuel vs air than it should) – common causes for this include:

• Dirty / Clogged air filter
• Faulty Fuel Injectors
• Faulty Carburetor (older cars)
• Engine Management System (computer) Fault

Blue Smoke

Blue smoke is a bad sign – it indicates that the engine is burning oil as well as fuel… This means that oil is somehow leaking into the engine’s combustion chambers. Common causes for burning oil include:

• Worn Valve Stem Seals (common on older cars but newer cars can also suffer)
• Worn Piston Rings

If you car produces blue smoke on start-up then this is a good sign it’s the Valve Stem Seals – if your car produces blue smoke under hard acceleration then that is an indicator of worn Piston Rings, luckily here at Shaw AutoPoint we have have the equipment to quickly test your piston rings.

In summary – if you car is producing a lot of white smoke or smoke that is either black or blue / grey then come and get it checked out – we are engine diagnostic specialists in the Oldham area, just call us on 01706 299155 or use our handy online booking form.