Smoke Signals: Why the Color of Your Car Exhaust Matters
The Darker or Oilier the Exhaust, the More Reason You Need to Get Your Car Checked
Lest you think checking the exhaust color sounds a little like reading tea leaves or divining the bumps on someone's head, it's really not quite that esoteric. Your car exhaust is the end product of how well the engine performs and what you put into the engine to fuel and lubricate it. By nature, junk in usually means junk out so always watch what you add to your car, truck, or SUV.
Despite using quality fuel and only the recommended oil, what comes from the car exhaust is a mess, you have reason to worry. Something within the core components of your vehicle is causing fuel and/or oil to break down, or fail to combust, in a way that indicates you have a problem. The root of the problem probably lies well ahead of your exhaust system itself, usually within the engine.
In a well maintained vehicle that operates in peak condition, you really should not be able to see the exhaust much at all. On a very cold morning, you may spot more apparent smoke, but this is simply the difference in temperature between the exhaust coming from a warm or warming engine and the temperature of the air. This is similar to what you see when you breathe or speak outdoors on a cold day: when you breathe, you see the condensation in a puff of mist coming from your mouth.
When you have cause for concern is when you can see the exhaust regardless of how warm the day may be. Different colors or qualities to the car exhaust usually indicate different degrees of trouble. A pale gray color isn't bad and some consider this a normal color.
But the darker the exhaust gets, the worse a symptom it portends. For example, black or dark blue oily smoke alerts you to a problem with the engine. It may not even be a deep worry, because you or someone who services your vehicle may be adding too much oil. The overage on oil has to go somewhere, so the car sends it back through your exhaust.
Yet oily smoke can also signal a failure in the integrity of your engine: oil is not staying where it should be so it's coming out through the exhaust. You sometimes see this on very old, poorly maintained vehicles, especially ones with lightweight aluminum engines that degrade after years of hard use. The moment you begin to see such exhaust appear, you need to schedule a trip to a trusted garage or mechanic for a full engine inspection. You may need a serious repair such as a ring job. In a worst case scenario, you may need to replace the engine.
Published by Kate J. Chase
Kate J. Chase is a journalist, columnist, and has written, co-authored, and edited more than three dozen books, dozens of magazine and newspaper articles and features, and hundreds of online reviews, how-to... View profile
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- Oily smoke can also indicate you are over-filling your vehicle with oil.
- What comes out your tailpipe indicates how well the engine performs.
- Lots of exhaust on a very cold morning, by itself, is not cause for concern.
9 Comments
Post a Commentall of you people are dumb if you have smoke comeing from your car take it in!
i have a 97 saturn and when i drive it an di floor it grayish smoke comes out what does that mean? let me know thanks
ok i just got dummer by just reading this... and im only a 2nd year apprentice and i know half the stuff she talked about is completely stupid.
""Rubbish Article, The darker the smoke, does not mean the more reason to get your car checked. Let's say you had white smoke, this could indicate a coolant leak. This can lead to serious problems if your coolant level goes below the required amount. So "The darker the smoke, the more reason to get your car checked" is rubbish. Kate please stop posting stupid articles about things you know nothing about""
this is true... white smoke can be from coolant/water leaks. this usely means the head is cracked, head gasket is blown, or even worst case the cylinder bores are damaged by flaking and corrosion. this will also create a very big problem in cylinder compression, especially if it is a diesel. without compression diesel will not ignite.
so really any color smoke that comes out of the exhaust can be a very big problem.
black smoke use
I have oil coming from exhaust. What couild cause this and what are the severities?
Rubbish Article,
The darker the smoke, does not mean the more reason to get your car checked. Let's say you had white smoke, this could indicate a coolant leak. This can lead to serious problems if your coolant level goes below the required amount.
So "The darker the smoke, the more reason to get your car checked" is rubbish.
Kate please stop posting stupid articles about things you know nothing about.
Dear Don
this indicates that you already have a problem in your pistons rings, when the car gets to its normal tempreture the rings get streched causing the oil to stay away from the gaz and air mixture but when its cold the rings shrink causing oil to pass into the mixture,,, so either you need a new rings set or even an oversize pistons you can never tell unless you get out the pistons and take the measurment of the cylinder.
I JUST BAUGHT A 90 GMC SAFARI VAN. RUNS GREAT AND VERY QUIET. BUT AFTER IT SITS A PERIOD OF HOURS THEN WHEN I START IT I HAVE SMOKE FROM THE EXHUST THEN GOES AWAY, DOESNT DO IT ALL THE TIME ONLY AFTER THE LONG SIT, IF ANYONE CAN HELP ME. PLEASE EMAIL ME WITH ANY HELP TO- BOOSER69@VERIZON.NET
this is a stupid article
A few notes I'd like to add in addition to the information already present.
Jumping to the conclusion that smoke indicates a serious problem is perhaps too quick of a judgment.
For example, gray/black smoke is often only an indication of too much fuel/not enough air in the mixture that's being ignited in the cylinder chamber... and furthermore it sometimes happens that such a problem can be correctable by replacing a few sensors under the hood.
Blue smoke too is often something that need-not create cause for excessive alarm. As engines age (not just aluminum ones) the rubber seals inside can begin to shrink and lose their ability to seal properly, causing periodic oil leaks which, in turn, lead to some blue smoke. If this smoke is frequent and does not go away after the car is warmed up then perhaps you can attribute the cause to piston-rings... though this kind of burning is very rare in cars that have not been driven ridiculously hard, and I would, personally, consider it