2003 Jeep Liberty using a quart of oil a week

So just bought this Jeep for a toy and i noticed blue smoke when I would start up and not while driving but when I would come to a complete stop and park or reverse it would smoke for a minute. So I did an oil change using Castrol 5w-20 high mileage 4qts with a bottle of Lucas oil stabilizer and actually now the smoke is gone it doesn’t smoke blue anymore that I’ve noticed at all. But I did notice today that I have already burnt through a quart of oil since my oil change and I’ve only driven about maybe a hundred miles if that. And I noticed a slight rattle in the engine when starting it up but once u drive down the road a few miles and come to stops or red lights the noise is gone and it isn’t misfiring at all so I don’t assume any oil is seeping in with the spark plugs yet… and I’ve looked for oil leaks around the engine and can’t find anything at all so I’m asking if I need a motor, can I rebuild this one or cheaper to replace with another used motor? And if rebuilding motor what parts would I need to replace internally? What is bad that is causing the oil to burn inside the engine? Oh and mileage is 240,000 on the odometer

I’ve always found installing a used engine as the cheapest way to go.

Tester

I figured buying new parts for rebuilding the engine would be cheaper than a used one I just worry with used engine what shape that engine is actually in.

The vehicle has 240,000 miles/

Whet condition is the transmission, rear diff, etc…in?

You don’t know what’s needed to rebuild the engine until it’s taken apart and inspected.

Tester

The transmission shifts perfect, fluid is clean, rear end doesn’t slip or hum. That’s all I know and surprisingly I would assume the motor would have leaks that I can’t seem to find so I wonder if this may not be a used engine someone already put in here considering the outside of it and gaskets such as valve covers aren’t leaking for the age

It doesn’t matter. The vehicle needs an engine.

Tester

I concur w/the advice above, sounds like you’ll be looking at used engine prices soon. But double check the pcv system, as if that fails, out of spec pressures in the crankcase & can cause weird oil consumption and oil seal problems. If the pcv system isn’t the problem, Ray has told callers on the show with engine symptoms like this to try higher viscosity oils and additives. That might further damage the engine over time but also might greatly reduce the oil consumption problems and buy you some time. BTW, better budget for a replacement cat too.

Two comments:

While the consumption of one quart of oil per week is definitely excessive, the OP hasn’t told us how many miles that represents.

My friend’s Rav-4 has been consuming too much oil for a couple of years, but because it “passed” the dealership’s oil consumption test, it didn’t qualify for gratis repairs from the manufacturer.
I check his oil weekly, and replenish it as needed. I had used almost every brand of oil over the past couple of years–including Mobil-1 when it was on deep discount at Costco–and every brand seemed to need replenishing at essentially the same rate.

A couple of months ago, Target had a really good sale on conventional Pennzoil, so I bought a few quarts for him. To my incredible surprise, the rate of consumption with Pennzoil is much lower than with any of the other brands of oil that we had previously used.

I know that this is counter-intuitive, but there seems to be some type of synergy between his engine and conventional Pennzoil that has dramatically reduced the rate of oil consumption over the past couple of months.