That’s what I thought… So any thoughts on where oil could be going in a brand new reman engine? Or what I should do about it?
Did you check with ATK? I’d be curious what type oil they recommend, as well as their thoughts on consumption.
They said go with whatever the engine recommends in the manual. Which is SAE 5w30.
I would go ahead and change the oil and filter - go with 5W-30.
Now, if we assume nothing is wrong; maybe the last oil change didn’t quite get to the full mark, and it didn’t use quite that much…
Once you get it home from the oil change, park it level, check it 5 minutes after engine off. Make a similar check once a week and see how it does. This will give you a more accurate idea of how it’s doing (and, you may have done this already, and I apologize - just looking for clues).
Using a significantly heavier oil in an engine, like 20W50 where 5W30 belongs, will not cause oil consumption today but will cause it in the future by causing excessive wear and friction and creating gaps in the engine where there were none before.
A very heavy oil like that will not flow to where it’s needed when the engine is first started causing wear. It is also not thin enough to get into the very small gaps between the piston “wiper” rings and the cylinder walls. There should always be a microscopic film of oil on the cylinder walls, in the cross-hatch grooves, to allow the rings to slide easily along the cylinder. Without this lubrication, the rings and cylinder walls will have too much friction resulting in worn rings and eventually oil consumption. The thicker oil may also under certain circumstances cause sludge more easily, leading to a different set of problems.
If the owner’s manual and the engine builder both recommend 5W30, use it.
Your engine is not entirely broken in yet, and as of now it’s only using oil at the rate of 1 quart every 5000 miles or so. I don’t think that’s cause for concern. See how much oil is being consumed between 5000 and 10,000 miles.
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I’m going to disagree on 20w50 increasing oil consumption. A new engine and a newly remanufactured engine have very small gaps between the bearing surfaces and the ring gaps. As the engine is used and wears out, it is these gaps that grow, increase oil consumption and eventually lead to an engine rebuild or scraping the vehicle.
As these gaps grow, some people switch to heavier oils like 15w40 or 20w50 to fill the gaps a little better. The lighter oils will flow out of the larger gaps leaving less lubrication, another advantage of the heavier oils in a worn engine.
It is the fact that the heavier oils do not flow out of the gaps as quickly as a lighter oil, especially in a new or remanufactured engine that is the problem. The heavier oil spends more time in these gaps where the friction is occurring, thus have to absorb more heat from that friction. Heat is the oil killer. It causes the oil to break down faster. Faster breakdown means oil consumption.
Now the difference between 20w50 and 5w30 is not going to cause a lot of oil consumption, maybe not even measurable when just using a dipstick as the measuring tool. But in a new (reman) engine, it may interfere with the break in of the rings, which goes on long after the initial break in period.
BTW, a quart every 5k miles is not serious. You should be changing the oil at that time anyway.