2. Bluish Smoke

Though it's easily mistaken for grey smoke, smoke that has a blue tinge can mean something different. Generally, this problem is caused by an engine that's burning too much oil. This is mostly likely caused by worn engine components, including the valve seals, piston rings, and PCV valve. In cases like these, serious engine work is typically called for since such wear of internal components means they'll need to be replaced.

However, there are other possible causes. One is too much oil in the engine. The solution to this is a little simpler: simply drain a little oil. However, you'll also want to get your car checked out, as too much oil can damage an engine. In addition, a faulty turbo seal could be the culprit if you have a Subaru with a turbocharged engine.

3. White or Grey Smoke

But if the white emissions are billowing and don't go away, you have a much bigger problem on your hands. This is usually caused by coolant leaking into one or more of the combustion chambers. Whether from a cracked cylinder head, a cracked engine block, or a blown head gasket, this will likely involve extensive work on the engine of your Subaru.

4. White Steam

There's a chance that the emissions you see aren't smoke at all, but steam. If this is the case, count yourself lucky! Steam usually isn't anything to be worried about. It's most often caused when condensation settles in the tailpipe while your car is parked. This is a common occurrence in the Pacific Northwest winter. When you turn your car on, the tailpipe heats up and turns the condensation into steam. If the emissions are thin and go away soon after your engine warms up, you'll have nothing to worry about.