I have a 2005 R52 S, roughly 163,000 miles on it. I checked the oil a few days ago and noticed it was almost at the bottom of the has marks on the dipstick. I poured a half quart in, but didn't think to check it right after.

I've driven 100 miles, and today when I go out to check it, I don't see oil on the dipstick. I pour another half quart in, and when I checked it again (without running it, but engine still warm) the level on the dipstick was back up to where it was a few days ago, at the bottom of the hash marks.

I haven't ever seen oil leaking under the car, nor smelled anything at all. What's causing my car to use 1qt of oil roughly every 100 miles?

 

Is this a one-time check or over many checks? Are you checking with the car level and in the same place every time? I think if it was burning it, you would have a lot of smoke or it would be pouring oil underneath the car. Especially 1 QT every 100 miles.

 

I’ve checked it probably one or two times in the last 150 miles. Primarily in the same parking spot, and it’s mostly level. Again, never seen smoke or anything leaking beneath the vehicle (also never smelled anything at all)

 

Have you checked the PCV?

 

Haven't looked into checking the PCV yet, but I've done a few more things:


First I checked in the coolant reservoir for any oil, and it seemed clean. Also my oil looks good, it doesn't look like chocolate milk at all.

I then pulled the spark plugs and they look fine, apart from the threads on a couple looked a little bit moist but the tips were dry.

A friend with MINI experience says it looks like it might be the rings, and to use something like 10W40 (I've been using 5W30) and Lucas Oil Treatment until the rings fully go out (He said I could make it run for a long time if I kept an eye on the oil and stayed on top of it). Does anyone have a second opinion?

 

You need to check oil levels in a consistent manner. Preferably cold in your driveway. Do you do mostly short runs?
Plugs look good. Squirt some carb cleaner in the PCV valve if you can.
Any signs of smoke? White = condensation or coolant. Black = fuel. Blue accelerating = rings, blue decellerating = valve stem seals.
At that mileage 5W40 or 10W40 is probably a good idea.

 

How consistent are you thinking? Also the owner’s manual says to check the oil several minutes after it’s been running.

Most of my driving is fairly short, though once, sometimes twice per week I drive 50-60 miles one way.

I haven’t noticed any smoke, but I need to have someone help me check that. Thanks for explaining the colors, I’ll look for that soon

 

Would Lucas Oil Stop Leak be a good thing to put in, or would that make things worse or complicate it?

 

As long as the car is in the same state each time you check it, I don't think it matters. I always check mine at home (cold) but some folks only do it at the gas station (warm). Personally, I'm not a fan of most additives; I think Stop-Leak is to fix leaky seals & if you're not seeing anything under the car it won't do anything. Try a big sheet of cardboard under the car for a few days. I do think a quality filter & oil change would be worthwhile; I'd try the 5W40; my thinking is that with mostly short runs the engine is just 'clogged-up'!
Again, personally, I'm not a fan of idling in the driveway to look for faults - or smoke. Without being distracted, look for smoke in your mirror, especially on your longer drives & when stopping & starting. MINI considers 1 quart of oil per 1,000 miles to be 'acceptable', by the way.
If the engine sounds & runs well, I don't think you have much of an issue - just keep an eye on it for a few weeks & top up as needed; MINIs do like their oil!
There are lots of other threads to look at.