Well, don't really know if it's an issue or not, but I'm bored and felt like starting a discussion,

Anyways...my truck typically uses about 1/2 quart of oil every 3-4,000 miles. Pretty darn good and nothing to raise concern. However, here recently on a 715 mile trip at all freeway speeds, it burnt a full 1/2 quart just in that period. I added a quart at the vacation spot bringing it back to full. The 800 mile all freeway journey home netted the same result; used a solid 1/2 quart.

Anything to consider? Not really worried about it, but did seem odd it'd do this when all other times are normal. Just a thought.

Oh...and for the sake of discussion, it has a MC PCV valve and no Fram oil filter....but you guys should know that already!

 

How old is your MC PCV?

I replaced mine at about 72,000 miles and my oil consumption went down (not that it was bad before).

They are really cheap so unless it is new I would start there.

 

Since this is just for fun, here's a bundle of assumptions for you. You're probably running more RPMs than the truck originally came with-gears and tires. I'd say something like 2100+ RPM at 70mph. The engine most likely has miles on the clock and is mostly driven in mixed city/hiway driving. Because of the mixed driving the engine block has a slight ring at the top of the cylinder, Because of the higher than normal RPMs the rods are stretching a hair which is normal but because of the ring at the top of the cylinder, yer burning a small amount of oil at these speeds. Kindly remember the piston velocity pays an important roll in this. At 2100 RPMs your piston is moving at the rate of 1458 feet per minute or if you like, 25 feet per second. Those are rounded off numbers. So consider those numbers before you think rods don't stretch a hair at speed. They take one hellava beating even in a stock engine. There's really no cure other than machining the ring out of it and that's called an overhaul. Thicker oil will help a little but not a lot. It's just an indicator of lots of miles on a normally driven engine....usually. YMMV. I disavow any of the above info. JEEZ, that was fun!

 

A condition called ring flutter that is generated in an engine at certain rpms. This condition can be dependent on several factors and it allows oil to flow past the rings because of the rapid movement of those rings. It can be a factor @ 1315 RPM but not @ 1435 RPM for example. It all depends on various conditions. Ring wear and clearance in relation to bore wall may be one of those conditions but there can be several as it usually is a stackup condition..One engine may have it another engine may not it all depends. You may have been using cruise control on the trip so you were in the RPM zone that was generating the condition in your engine. We used to see it during dyno testing when the computer would run the engine for long periods of time at one specific RPM and we would experience increased oil consumption. Change the RPM by a 100 or so RPM and it would stop.
Then again that may not be the cause of the problem at all it may very well be what others here have stated just a possibility. Take care.

 

Isn't Piston slap the manly word for that DT ?

 

I wish my truck used that much......

I change my oil every 3k miles and there are times I only get 2 or 3 quarts from the 6 I put in. Until it locks up on me, I'm not going to worry about it. Been doing it for the past 3-4 years and at 300k miles on the clock I'm not worried.

 

At this point Galaxy, you'd have nothing to lose by adding MMO ( or try HM oil) to the crankcase. It could be a sign that your oil control rings are starting to stick. Many anecdotes report it does the trick in this scenario.

My 200k Triton used 5w20 fast so i switched it to 5w30 and it brought it way down, a sign of wear. The wear must be in the ring pack because she doesn't smoke at all on start-up even after a long sit.