hey,
so a little background info. I run Royal Purple 5w40 and found I had the best pressure and valve train noise with that weight.
for random cruises around town, furthest trip being about 180 miles one way, some hard driving locally. I could leave my catch can for an entire oil change interval and when I went to drain it I'd get maybe a shot glass worth...maybe a touch more.
last week I went on a 4500mi / 6800km road trip. It was basically non stop. I'd do about 1000mi per day. I randomly decided at the 3rd fuel fill up to check my catch can and it was basically full! I pulled out almost a 1/4L. after that I started checking it at every 2nd fuel fill up and I was getting a large amount each time.
Other then the catch can oil, my oil level was perfectly fine so Its not consuming any elsewhere.
Is it possible with the heat and running time, my oil was boiling off or turning into a mist or something?

 

Interesting theory... and it's certainly possible.

Every time I enter a metal machine shop where they are using oil products during machining that stuff is in the atmosphere. Even if they are using automated equipment and it is enclosed it still seems to be in the atmosphere like a vapor.

I have to believe it's the internal baffling of the rocker covers my self. I believe they sit too close to the rocker arms. As the stuff is being whipped around it gets sucked right through as a vapor. I don't necessarily believe its heat related.

Between that and the vacuum being pulled during you're long trip.


That's my theory any way.

 

I would maybe try a different oil. Its a cheap test at the very minimum

 

try a 10-40 oil. mine didn't like the 5-30 so i moved up,
fixed oil prob.

 

When your out on the interstate with the cruise set your engine also see's higher loads. I would guess that it was a combo of running the engine for extended periods of time with increased loads(other than back roads and stop/go city traffic)and it was just sucking it outas its being whipped around. I believe oil does kinda vaporize during heating and just over time in general. I would see if it goes back to normal when you begin driving normally again. How high or low is the catch can mounted? I can see how it disturbes you though because think about what would have happened if you didnt have the catch can in place.....

 

I would never run less than a 10w-30 or 10w-40 imo other stuffs so thin I can believe it to "disappear" when in hot bumper to bumper traffic.

191k on my 6.0 chevy 10w-30 Castrol high mileage all it gets
103k on my 5.7 hemi truck switched to 10w-30 10,000 miles ago great pressure , and quieted that dreaded hemi "tick"