exhaust

Stop Smoking – what does smoke from your car mean?

5th Mar, 2019

Some experts like to compare a car to the human body. And if we’re running with this analogy, while that makes our line of work at Scrap Car Network slightly more depressing, it’s understandable why so many people find it helpful. If something’s going wrong in your car, just like a human body, it has a way of instinctively reacting. To certain problems, this reaction can take the form of emitting a certain colour of smoke. Don’t panic if you see them – you may not have to scrap your car just yet! We’ve covered the major details of the four of the most common colours below, what they mean, and whether you should be worried.

What does black smoke mean?

Black smoke is no doubt the most panic-inducing of the four, but you may be pleased to hear the problem may not necessarily be all that bad (although you should still take your car to be inspected, just in case). Most commonly, it tends to mean that your car is burning too much fuel. For whatever reason, it may not be making the right air to fuel combination – this may be the due to problems with intake components like sensors, fuel injectors, fuel pressure regulators, air filters, or even the engine manifold. It lowers your fuel efficiency quite substantially, but happily it’s often the easiest to fix.

Black smoke

Watch out for white smoke

You might see white smoke from time to time already, and like black smoke, it’s not necessarily indicative of an immediate problem. Thin vapour is reasonably normal from time to time, although if you’re seeing it often when you’re taking your car on a lot of short journeys then it can start to be an issue. In these cases, your engine may not have a chance to fully warm up. Over time, this can cause the buildup of rust and other types of corrosion on the internal components, which can eventually lead to an MOT failure.

Thick white smoke, on the other hand, can be even more worrying, as it’s often a sign of coolant leaking into the engine. Eventually, this can lead to a blown gasket, or even the failure of the entire engine. Not good news, by any means!

The meaning of blue smoke from your exhaust

The sight of blue smoke is almost always accompanied by a slightly sweet, acrid smell. That means engine oil is getting burned off in the car. Now, your car normally burns a small amount of oil in the combustion chamber, but it’s getting to the stage of affecting the exhaust smoke, that’s obviously not ideal. However, it might not be anything to worry about offhand; if you’ve recently had your car serviced, that can provide an explanation. Engineers normally fill the engine up with fresh oil, which then gets quickly burned off. It’s probably wise to check with your garage or engineer for reassurance, just in case. You can also check the dipstick to see if you are indeed burning up oil at a higher rate.

If the smoke is more persistent, though, it may be a sign of some slightly more serious issues. The valve seals or piston rings might be worn out, or you might even be approaching a head gasket failure. Get your car booked in, just in case!

Don’t ignore grey smoke

Grey smoke isn’t quite as common as the others, and the exact cause can be tricky to pin down. It might well be burning oil, as with blue smoke (the line between them is quite a thin one). It could also be down to a faulty turbocharger, or leaking engine seals. Another alternative (or even additional) explanation is PVC valve failure. If you drive an automatic vehicle, it might also be a sign that transmission fluid is leaking into your engine from somewhere. While some of these issues are more complex and expensive than others – you really don’t want problems with your turbocharger – we’d always advise seeing a mechanic for any of them, just in case. A common resort for drivers is just to ignore them for a bit until they go away, but it’s really not a course of action we’d recommend!

And of course, eventually the time may well come when your car is just not worth the time, money and effort it’ll take to repair. For when that day comes, we’re right here for you at Scrap Car Network! Just enter your car reg and postcode into the fields above, and you’ll get an instant online quote for your scrap car. No paperwork, no fuss, no hassle. That’s the way we like to do things here at Scrap Car Network.