Black Exhaust Smoke Out Tailpipe of My Car

I have recently bought an older second hand car and I’ve noticed in the mornings or whenever the engine is cold and I first start and warm it up, that small splatters of oil and water comes out of the exhaust pipe. It appears that there is a black looking smoke coming out the exhaust, but I’d like to know whats wrong because its slowly staining my driveway.

Thanks,
Justin

Hi Justin,

Sounds like your engine might be running “rich” and what you see is soot, or carbon not necessarily oil, mixed with the water. If this is correct, you might want to look at getting a tune up, spark plugs, wires, distributor cap and rotor etc. etc.

Is the check engine light coming on? Usually when I see vehicles with black smoke the engine warning light is also on because the fuel to air mixture is out of control and the computer notices it.

Also if you have black exhaust smoke, I would expect to see a substantial drop in fuel economy, since you are dumping too much fuel inside the engine. So much fuel that the engine can not burn it all efficiently and the remaining fuel is being pushed out the tailpipe.

If you do not fix the problem you will stop up the catalytic converter, which will be pretty costly.

There are MANY electronic sensors on today’s vehicles and many of them control fuel and air mixture and emissions. If the check engine light IS coming on, start by reading the computer codes first before just guessing at spark plugs etc.

Carbon and water will stain the concrete but will not leave a slick oil residue like oil and water will. Take your finger and stick it in the tailpipe, is it a powdery carbon substance, or wet slick oil?

If you are positive that is oil, not black carbon then you might have some worn out seals inside the engine itself. A compression test of the pistons would be the first thing I would do to make sure that is the case.

Using thicker weight engine oil, and some of the over the counter oil additives can help reduce the loss of engine oil. Talk to your mechanic and see what they recommend for your climate area. Using thicker engine oil in cold freezing areas is not a good idea, since it makes the engine work harder on very cold start ups.