Hey Gang,
I accidently overfilled my motor oil on my 207 Mini Cooper S. It is about 3/4" above the full indicator
Will the higher oil level cause major problems or should I drain some and start over?
THanks
Lee

 

You should either drain or siphon away the excess oil because it could possibly cause engine damage (crankshaft can come into contact with oil which will result in foaming and the introduction of air bubbles into the oil pan pickup). If you have access to a siphon-type oil exchanger you can suck out the excess oil through the oil dipstick tube. Otherwise, you will unfortunately have to drain the oil from the drain plug and start over.

 

Ideally, you should remove the excess oil. It won't immediately destroy your engine, but it will create extra oil vapor in the crankcase, which will then get passed through the PCV into your intake. Oil vapor in the intake of the S engines leads to deposits on the valves, which is a known problem already with these engines anyway. Having too much oil in the engine will accelerate that process, as well as reduce your fuel economy.

 

I do not have a manual for my MINI...is the oil drain plug obvious from the bottom?
THanks
Lee

 

Yes, quite obvious. I changed my oil last weekend and accidentally overfilled a little also, so planning on draining some off tomorrow. You should be able to just loosen the plug and let it drip out slowly, at least that's my plan. I want to avoid completely draining and refilling.

 

it is obvious, and is a flush fitting hex head bolt 8mm, some say they've found a torx, and while a T-50 certainly fits in mine, once I had the plug in hand it was most clearly a hex head. Mine is a 7, so maybe they changed, but mine is for sure a hex and not a star/torx.

Do NOT confuse it with the similar transmission drain plug! This one is way over to the driver side while the oil drain is more near the centerline, sort of below the oil fill.

You can easily loosen and drain a bit, no need to flush and start over.

 

I drained off an excess quart of oil today. I guess I need to be a little more careful adding oil next time I do a change. I don't think a week (250 miles) of driving with excess should contribute much to carbon build up on the valves, but glad I figured it out and took corrective action.

 

Carbon buildup is a very insignificant issue (besides I highly doubt you would have built up any significant carbon deposits in 250 miles) compared to the crankshaft hitting the oil and causing it to foam. When oil foams, you have the potential of air bubbles getting sucked up by the oil pickup and starving the bearings of oil. But, anyways glad it all worked out for you .

 

+1

Cavitation is the big worry. No one knows how much of an overfill does this. That's the $10,000 question. Best add the correct amount.

 

I assume that 207 is 2007. Here you go:

http://motoringfile.com/files/2007_MINI_Hardtop.pdf

http://motoringfile.com/files/2007_MINI_Convertible.pdf

 

My dealer always overfilled my car and I never bothered to drain any of the excess out. I has a piston fail at about 28k miles and a number of other engine problems, but I'm doubtful that them overfilling them caused those problems. Anyways, I would drain out the excess if I owned the car and wanted to keep it for a long time.

 

I disagree. Based on my knowledge (and it is a bit more than a little) so I am not dangerous overfilling oil can cause significant damage over time. Pistons. crankshaft, gaskets etc. If you are still using this dealer I would stop going there. I only over filled one time and I quickly drained the quart or so out.

 

Overfilling is often done at the dealer, where mine uses 5qts on an oil change, and about 4.5 is the right amount. But I don't think that % of overfill is gonna damage anything it's about 10%. But if you add an extra whole quart you could have problems over time. Just my .02.

 

As someone else who has accidentally overfilled by 1/2 qt ; I drained off approx. 1/2 qt but I'm still seeing puffs of smoke after pulling away after idling. I have been told that it will take some time for any oil vapor sucked into the intercooler and other parts before it clears up. Is there any other way to clear it up?