Let me guess - your oil gets gray due to lead sludge, rather than
coffee colored like my 172. You probably have a very tight solid air
baffle system with little gap developing under air pressure loads, the
engine cooling fins are clean, and the alignment of the casting molds
for the heads happened to be very good at the Lycoming factory. All
good things that make for good cooling, and a good piston ring
break-in.

Your oil consumption is higher than mine but acceptable of course. I
get about 30 hours to a quart, and see no increase in consumption
despite the high time. I cruise at lower power settings and try to
keep the cooling system in perfect order.

We bought the airplane when it was new so I'm the only pilot. My
primary concern now is when to major it as a matter of principle. I
doubt I could get back to the present smoothness and oil consumption
even after a major, so barring any changes, I'm still inclined to
leave it alone. Lycoming says to major every 12 years, which would
have put me halfway thru a second major. But really, taken care of,
they seem to run almost forever.

I covered the oil cooler air inlet last winter to get some semblance
of warmth. When the cover was left (forgotten) last spring, it got
warm (but just upper green) fast. Otherwise it usually only can get
to the bottom of the "L" of "oil temp" on the Cessna gage.

I also feel Cessna has a superior baffling system for their Lycomings,
compared to Piper, and especially to Grumman.