M Allen Duncan

I have a 97 D16Y7 SOHC Civic DX. It spits this black chalky wet crap out of the exhaust. I have searched and can't find any info. What would be the cause. The black stuff doesn't smell like anything but exhaust and it shoots about 5 feet when you raise the RPM.

LiteraCola

Sounds to me like carbon build-up mixing with the condensation from the exhaust; perfectly normal. Seafoam the intake for good measure and don't worry about it.
How old is the catalytic converter?

M Allen Duncan

Cat is unknown. There is also some white smoke, not a lot, just some. No car I have ever had spit out this much moisture. I'm thinking piston blow-by but not sure.

mk378

Some black soot is normal. My car leaves a mark if it sits in one place idling for a long time. As the engine wears and burns more oil, there will be more soot. If you have black smoke coming out while accelerating, the fuel mixture is wrong.

Water is one of the resulting products when gasoline is burned. If you ever notice in traffic you will see lots of cars with water literally running out of the exhaust pipe. After driving long enough to heat up the exhaust, the water will stay as steam and is generally invisible.

TomCat39

I will x2 everyone's comment that this is normal. Higher mileage cars tend to have more carbon build up and it spits it out. Especially in the mornings.

My 2007 Si has 370,000 Kilometers on her and I park with her back end close to the garage door. I have to continually clean a black circle of carbon "chalk" off the door from morning start ups.

The "white smoke" you are seeing is most likely steam. It is winter/cold weather time and it takes a lot longer for the exhaust to evaporate off the water that condenses in the exhaust when it cools after parking for any duration.

M Allen Duncan

Thanks for the feedback. I pulled the plugs today. 1/2/3 were good but #4 was completely soaked and the well was full of oil. Im thinking maybe spark plug well seals on the bottom of the head.

TomCat39

The Y7 doesn't have lower plug seals only the seals on the top of the well. The seals are in the valve cover.

Was the business end (combustion chamber end) of the plug normal?

M Allen Duncan

Good info. The plug was black and wet.

mk378

That means either burning a lot of oil or running rich. Have you noticed how much oil it uses? Does the car make smoke when you drive, and if so, what color is the smoke? Have someone watch from another car. It takes a LOT of smoke to see it yourself in the mirror.

M Allen Duncan

Truthfully I think it was one of the valve seals on cylinder 4. I swapped the head and the problem hasn't returned. Thanks for all the help!

holmesnmanny

it's actually not that hard to replace the valve seals with two tools


that removes the seals


that removes and installs the valve springs

https://www.youtube.com/results?sear...ry=lisle+36200

M Allen Duncan