2001 Civic 4DR LX - 5 Speed

I have had this problem since I bought the car last Nov. I am losing about a quart of oil a week (more if I do a lot of highway driving).

It is not leaking on the ground, and it is not blue smoking. The only thing that has been tried is changing the PCV valve. Other then that we cannot figure what might be happening to it.

As a foot note one other thing I noticed, the oil seems dark (almost black) all the time and was this color just days after my last oil change (I check the oil everyday or so as a habit). This is my first import so it may be normal, when my sunfire's oil turns this color it usually signals that it is time for a change.

Any ideas would be appreciated.

Thanks.

 

Possible headgasket leak.

 

a quart is a lot through the head gasket. it may not be enough to leak without pressure, but I assume you've left it running to see if it drips while standing still. If its black... then something is burnt, or stuff is possibly getting in from someplace it shouldnt. I'd worry that its the bearings or something but if the car is otherwise running normal, then it isnt. What else is the car doing?
Check around the valve cover, both sides of the cam, between the engine and transmission, and behind the crank pulley. Those are all the seals that keep the rotating stuff closed. If one of those went, you may or may not see it on the ground (especially the cam seals) but it would come out at a pretty good rate.
If no luck, do a leakdown, make sure the rings are ok.

 

I one other symptom I forgot to mention, the knock sensor turns the service engine light on randomly. It seems to be when the oil level is below the half way mark on the dipstick. It may or may not be related.

Also I have let it run and it sits in the same spot in my drive way and I never see any sign of oil on the ground.

I will check the mentioned locations, thanks Boilermaker1