I have a 2001 Jetta Wagon (Golf Variant is caller in my country). Petrol engine. Usually rides school and back (15 miles) with engine between 2000 and 3000 rpm. Just did a 300 mile trip at 3500-4000rpm. Next morning I noticed smoke and dark water coming out of the exhaust. Coolant is not dirty, smoke has decreased after coming back another 300 miles, but when I start the car it "spits" black soot/water.

What could be the cause?

I know some water out of the exhaust while it"s cold is normal, but in this case, it happens at every start, even with a hot engine, and the soot is considerable. I"ve just seen a Mazda drip a few drops, which is normal, but if you see the video linked there is a lot of water and soot.

You are watching: Black soot coming out of tailpipe

The electronics in the car are not working very well either.

Edit: There is no overheating, No oil in the cooling fluid and no other symptoms.

Video of the actual problem


engine vw exhaust head-gasket smoke
Share
Improve this question
Folshort
edited Oct 16 "15 at 12:51
*

George
6,4653030 gold badges7171 silver badges117117 bronze badges
asked Oct 13 "15 at 14:13
*

marianovmarianov
16111 gold badge11 silver badge55 bronze badges
3
Add a comment |

4 Answers 4


Active Oldest Votes
6
There is nothing wrong, water is a byproduct of gasoline combustion.

2 C8H18 + 25 O2 → 16 CO2 + 18 H2O

where C8H18 is the gasoline reacting with oxygen (O2) and giving Carbon-dioxide (CO2) and water (H2O) as the byproduct.

So, this simply is:

2 * Gas molecules + 25 * Oxygen Molecules → 16 * Carbon Dioxide Molecules + 18 * Water Molecules

So the black soot is just water mixed with carbon in exhaust pipe.

Water usually comes out when engine is not hot enough like when starting it. So the liquid water drips out of exhaust with the carbon mixed in it making it black. But after driving a little the engine becomes hot and so thus the water and it comes out as steam. So you don"t need to worry.

EDIT :

In some cases the cause of water leaking from exhaust is a blown up head gasket, or cracked head, but that also results in overheating of engine. Since your engine is not overheating so i would say that it"s just water getting accumulated in our silencer and coming out when you start the engine.

See more: What Is A Mossberg 500 Worth, Mossberg 500A Shotgun Price And Historical Value

I can"t say much about the electronics, maybe just some wires got loose. You should probably get that checked by someone in the garage.