I have a 2010 Clubman (non-S) that I've been driving for 14 years, with 154,000 miles on the clock. I'm having a lot of various (possibly connected?) issues that have me stumped.

About a year ago, I replaced my factory ignition coils with aftermarket coils (Duralast). After about 1,000 miles, they started to fail one by one. I assumed it was a bad batch, so I would replace each coil under warranty--only for them to fail again (they should change their name to Doesn'tlast). After several rounds of replacements, I caved and ordered Bosch coils, which have been running fine for 15,000 miles now.

Around that same time, I started to see blue-ish smoke from my exhaust after idle/takeoff. Since I still had the factory valve cover, I figured it might be a failing PCV, so I replaced it with an aftermarket valve cover. Soon after, I started to see the smoke again, so started to suspect something more insidious, like valve stem seals or piston rings. Perhaps I messed up again by buying aftermarket parts? My MINI-certified mechanic suggested it was likely stuck piston rings, and I could improve/resolve the issue by changing the oil every 3000 miles, running Liqui-Moly engine flush, and adding Liqui-Moly oil saver each time. After 4 oil changes, I've gone from losing 1 qt / 750 miles to every 1 qt / 2000 miles, which is almost as good as it's ever been. But the smoke is as bad as ever!!?

Somewhere between the misfires and burning oil, my catalytic converter is cooked (I have the dreaded P0420 code). However, the car still runs okay with slightly sluggish acceleration, so I've been putting off replacing it until the oil burning issue resolves/improves (I don't want to foul up another). But recently, there's been a strong gasoline smell when I start the car. I ran the OBDII tests and the evap monitor shows within range (attaching full results below). So I have a long list of questions:

• Is 1 quart of oil per 2000 miles really that much for a 2nd gen MINI?
• Is there a way to positively diagnose a bad PCV vs. piston rings vs. valve stem seals?
• If the oil loss has improved so much, couldn't that indicate that the smoke is something else entirely?
• Could the smoke be from the failed cat?
• Would the evap monitor always detect a leak in the fuel system?
• What else am I missing here??

Sorry for the novel, just trying to keep my little car happy! My mechanic is in the process of moving shop, so they won't be open for a few more months. I'm willing to do all of the work I physically can, so let me know if you have any ideas!!

 

Had another car (not a MINI) manifest a P0430 code. (The same code as P0420 just referring to the converter on the other cylinder bank.) The factory manual called for if the P0420/P0430 code was accompanied by O2 sensor codes to replace the sensors flagged by the codes then clear the codes and road test the car. If the P0420/P0430 code returned to replace the converter flagged by the code.

Long story short I replaced the converter with a used one. (Factory converter was over $1000 and this was about 10 years ago.)

Replacing the O2 sensors is sort of throwing parts at the symptoms but 154K miles is pretty darn good O2 sensor service life. Only had two cars that I owned for big miles that required O2 sensor replacement. One car required new sensors every 80/100K miles. (In total I put 317K miles on this car.) The other car required new sensors at 132K miles. I put 151K miles on this car.

The saying is with cars/engines there are always two problems, unless there is just one or 3 or more...

But before you replace the converter think you need to ensure the engine ventilation system is working properly.

My 2nd hand info is aftermarket MINI parts are in general no good. You experienced this with the coils. I've read posts of owners reporting problems with aftermarket valve cover/PCV hardware. And cam drive hardware and so on.

Thus is could be both new *factory* sensors and new *factory* valve cover/PCV/etc could be the cure.

There is probably a way to diagnose a bad PCV system. I can't put my hands on this info but I vaguely recall it involved checking crankcase pressure. Too little (or too much) can condemn the PCV system. With another car/engine it had 3 air/oil separators (AOS) go bad (in over 300K miles) and each time the failing AOS subjected the engine crankcase to too much low pressure. A prominent symptom was the engine smoked at cold start which was a real red flag as the engine didn't do this any other times. As the condition got worse the engine smoked at warm/hot start and then all the time.

Might add that a bad MINI valve cover/PCV/etc could account for some of that 2K miles per quart oil consumption.

As I mentioned above regarding replacing the converter same too for valve stem seals, rings, etc. at the smoking you might consider factory valve cover/PCV and any other associated hardware. However, I will offer that there are some people more (way more) knowledgeable than me who pretty much just advise an engine refresh at fewer miles than what is on your car's engine.

An engine refresh will should also include a new valve cover/PCV/etc. If I faced a situation similar to what you are facing I would not be too bothered by first replacing the valve cover/PCV/etc. hardware to see if it addressed the smoking and possibly other symptoms/problems. But of course you have to decide what you think is best for you.

As an aside, 2K miles per quart of oil ain't that bad. Yeah, some owners will report no oil consumption in 5K or even more miles. But with an engine with 154K miles?

Think a rule of thumb for classifying oil consumption is excessive -- to the point the factory would step in and address under warranty -- is if consumption gets to 1 quart every 600 miles or 1 liter every 1000km.

The engine controller can (and does) manipulate the evaporation system to check for leaks. But my info is it is better at detecting big leaks but not so good at detecting small ones.

A smell of gasoline upon cold engine start is not necessarily a concern. The O2 sensors and converter are cold. At cold start the engine controller purposely provides a rich mixture which provides the converter with an excess of fuel which burns in the converter and helps bring it up to operating temperature quicker. A general rule of thumb is after a cold start and when a short time later the elevated cold idle RPMs drop to hot idle RPMs the converter is up to temperature, ditto the O2 sensors, and the engine controller has switched from open loop mode operation to closed loop mode operation. In closed loop mode it will more precisely fuel the engine and the result will be -- if everything is working right -- an exhaust gas that is most efficiently processed by the converter.

The flip side is a smell of gasoline from the car when parked and say left in the sun or from the exhaust with the engine running and up to temperature this can be cause for concern. Absent odor of gasoline at these times -- and absent any evap system error code -- I'd be inclined to put any concerns about an evap system problem on the back burner.

 

Remove the coil cover. Do you find engine oil leaking from the PCV diaphragm into #1 spark plug tube?