Further, oil loss out of the breather is a great indicator of excess blowby and should be investigated.
Possibly.
Oil loss out the breather is also very possible with a normally running engine when the engine is overfilled. One can be within the rated and posted capacity for the engine, and still overfill it . There are no shortage of engine out there that tend to run two quarts below their sump capacity, and will blow the extra out quickly. Thus it's possible to keep losing a quart an hour and have an engine that's not consuming oil and has no blow-by problem. If oil is being added above the normal running level for that particular engine, then one should expect to keep seeing it blown out. This is why I stated in my original post that not enough information is provided. We may be hearing about a perfectly normal engine; oil consumption alone is an inadequate indicator of engine health, without more information...as is oil color.
Our continental O-200 is using around 1L/ph of oil in moderate cruise, which concerns me. The oil pressure is also very low (just in the green).
The original poster didn't indicate the starting oil level. If it's a six quart sump and six are being put in...one might expect a quart or even two to be lost over the course of a flight. If one continues to operate the airplane and sees no further decrease in the rate of oil "use," then all that has happened is the engine has sought it's natural operating level. This post, providing very little information, does nothing to suggest that the engine is beyond it's overhaul limits, or that it's no longer airworthy.
The inclusion of a statement in the same sentence stipulating low oil pressure makes the condition sound as if the two are tied together,when indeed this may or may not be the case. Tweaking up the oil pressure and determining whether the engine is consuming oil or simply blowing out extra is important before passing judgement suggesting overhaul or maintenance. The engine may be perfectly fine. In absence of any further useful information from the original poster, we are left without anywhere to go.
Could be your anual retentive attitude
No. I don't have an anal retentive attitude.
The owner was too stupid to bother tracking oil consumption...like many operators out there. Ignorance is bliss, until it bites you in the ass.