@cmt52663 I've got a new one for the thread. This may or may not be unique to the B46, and hopefully it doesn't come up for a lot of people.

At approximately 108500 miles (I am now over 125000), I found an unexpected oil leak at the bottom starter attachment bolt. The starter obviously doesn't have any oil in it, so this was a complete surprise. The note I made at the time was:

I'll put photos I took at the time at the end of this post for reference.

Since then I have been watching this, and it has not gone away. I have asked a couple of trained BMW/MINI techs who opened their own shops about it, and their best guess was rear main seal or oil pan gasket. As the oil pan gasket is RTV, I really don't want to mess with that unless I have to, and about the only worse thing would be to deal with the cost and consequences of pulling the engine because "maybe" something is up with the rear main seal.

Whole lot of "ugh."

Well, I did an oil change yesterday and noted the same thing still going on. Also, the car is definitely consuming oil -- maybe 1/2 a liter within a 5000-mile window. Whether it is worsening or staying the same is tough to tell. But all that prompted me to Google up "b46 engine rear main seal." And wonder of wonders, courtesy of a Reddit discussion started in April 2023 and updated about 28 days ago, I got an answer -- a really unexpected one, yet to be confirmed on the B46 on my 2017 F56 S, but definitely a whopper of a find.

Links to the Reddit discussions (I'm including two, both started by the same user, because the photos in both are useful) below. Spoiler: the oil pan *itself* was leaking. Literal seepage through the pan. Rear main seal and oil pan gasket both dealt with and the leak continued, until the oil pan itself was replaced.

Reddit discussion 1, "B46 oil leak", in forum r/BmwTech: the first one I found, photo within shows the user's oil on starter bolt (exactly where I found and have been monitoring my leak). 19 August 2024 comment in the discussion from the original author says "The source of the leak in this post was oil seeping through the oil pan itself. I made another post about that. Replacing the oil pan stopped the leak."

Reddit discussion 2, "B46 oil pan leak", also in r/BmwTech: From the same user, more detail on the troubleshooting to ultimate resolution. The photo in the thread is with the engine out of the car, and the back of the oil pan wet with oil, apparently seeping through the oil pan itself. Disclose in this thread of the final fix being replacing the oil pan outright was 27 July 2024. The author went back and updated the other discussion with this resolution the following month.

End to end it took this person over a year to get root cause identified as the pan proper, with the oil pan gasket having been replaced in May 2023 and the rear main seal having been replaced in late October 2023.

The author also made this interesting comment with regard to the rear main seal proper (meaning dealer ability to get a new part): "They had trouble getting a new seal in the US that was not defective, according to them. They said all 3 seals that were acquired were not uniform either from manufacturing or shipping." That particular comment was from 4 October 2023.

I have never heard of leaking aluminum before, but they do get into that in the second discussion, with one person speculating that it might be a bad casting and another saying "I’ve seen this with ZF transmission cases seeping like that but not an oil pan. Still a cast piece of aluminum so it’s entirely possible. Of the thousand of B46/48 engines I’ve repaired and serviced I’ve never seen that."

For my part, I will probably wait until either BMW/MINI puts out a TSB about this or my leak gets worse. No point in tearing up the car in any way until there is either an acknowledged issue and tested fix, or it just becomes a "must handle now."

Fun one, this one. Figured this thread was a good place to document it. Pics of my own leak below, taken on the day I found the leak.

 

Just brought these bremmen parts pans in as we have heard of some issues with the oem pan. The OEM pans are expensive also.

https://www.northamericanmotoring.co...ig-a-deal.html

 

I haven't posted in a long time, but figured I'd list my issues for potential high mileage buyers:

2014 F56S (B48) with 140,000 miles

My issues:
1. Failed front seat sunshade cover
2. Windshield wiper fluid reservoir leak
3. Sluggish acceleration sometimes (has happened since new). I recently replaced the spark plugs and mass airflow sensor, but it didn't help. I read there's an ECU update at the dealership, but I haven't scheduled it yet
4. I parked after a 500 mile drive last month. The next morning, it misfired on all cylinders after a cold start. I restarted the car and it's been running fine since then

Everything else has been working great, not bad for a first year model of the F56. This is my 5th Mini Cooper and they've always been a handful. Not as fun to drive as the previous generations, but it's easily been the most reliable

 

There have definitely been software tweaks that include DME-side engine handling changes since my 2017 F56S (B46) was built in 10/2016 -- I had an update done a couple of years ago -- so stands to reason there is also stuff that applies to your 2014-vintage B48-carrying F56S. Very very interested in how the software update helps or doesn't help once you've got it done -- let us know when you have it scheduled and the result?

Q: Have you ever replaced the coils on the car?

 

One more for the pile: Warranty Extension (MINI USA): Evaporative Emission Control (EVAP) Purge Valve.

Fun fun

 

Let's not overlook the excellent info shared here - on Counter Balancer Cover Oil Leak that appeared for one owner at about 110k miles. Gollum hasn't seen that one... (yet).

This thread is getting kinda useful as folks pitch in - I am very pleased. CJv2 your post from the 16th might have saved be some coin! HERE.

Cheers,

Charlie

[[url]https://www.northamericanmotoring.com/forums/f55-f56-hatch-talk-2014/366904-leaking-counterbalance-shaft-cover-seals-gaskets-anyone-run-into-this.html]
[[url]https://f30.bimmerpost.com/forums/showthread.php?t=2008030]

 

FCP Euro just impressed me with their review of the B48 (B46) which taught be a bit I did not know!

HIGHLY recommended...

BTW Gollum is at 142k miles.



Cheers,

Charlie

 

That is a REALLY informative video. And I'm turning off my auto stop/start like right now. And it totally validated my not-so-wacko plan to replace every plastic cooling system component I can lay hands on, on a fixed interval. Wowzers.

 

Gollum is now at 167,000 miles (and change), and since replacing the oil cooler and water pump (the plastic silly bits on the front side of the block) we've had no issues worth fixing.

Issues NOT yet worth fixing include:
1. a minor seep from the plugs that secure the balance shafts
2. a proximity sensor that no longer hollers if I back up too far (video is fine)
3. corrosion on the hard line feeding the clutch slave cylinder
4. corrosion on a tiny braided cable that is part of the starter assembly, providing a ground
5. parking brake cables that cannot be relied on to fully release when the brake is disengaged

We'll take these as they become critical, as the total estimate to heal all of them is just over $5,000

Mileage is slightly off from 27.9 to 27.2, but winter does tend to use a bit more fuel.

Performance and reliability are still splendid, and Gollum is a rambunctious joy to drive when I tickle him.

Cheers,

Charlie

 

Good to hear the little engine is still going strong. I’m working my way up there in the F60, likely to cross the 100k mark in the next month or so. I have an aluminum oil cooler housing and water outlet pipe sitting on the workbench, waiting. I’m contemplating changing out the thermostat “while I’m in there.”

 

I just crossed 116k and have to say that replacing the oil filter housing unit is the single most important item to address. It WILL fail, eventually. Mine was close to failure when I got it done a few thousand miles ago. My shop was impressed with the upgrade to the aluminum filter housing and connector pipe.
https://www.northamericanmotoring.co...uto-trans.html

I just had Koni Special Actives installed all the way around. Oh boy, what a massive improvement in ride quality! Highly recommended, especially since the original shocks/struts had 115k on them. Even my wife noticed the massive ride quality improvement, which is saying a lot.

Next trip to the shop will be the water pump and possibly a walnut blast, if it even needs it. I'm seeing quite a bit of references to the B46 not exhibiting issues with carbon build up on the valves, or a least not as bad as the previous Mini engines. Easy enough for them to pull the intake and check it out though.

I have this post saved so I can keep track of the items that have been addressed here. Ultimately, I plan to drive this car as long as it will go and want all issue handled timely.

 

If you're going to change out the thermostat, may as well change out the water pump and its plastic impeller at the same time. A Meyle HD has a metal impeller and the cost is not onerous (or at least it wasn't when I did it a couple of years ago). Go big or go home lol

 

When I replaced my oil filter housing (101K miles) I pulled the intake and figured I may as well, being familiar with the coking issues on the N series / Prince engines, stick the borescope down there. I recall 1 cylinder looking dirtier than the others, but absolutely nothing even approaching what I would even call carboning or coking up in a way comparable to those N series engines.

Berryman's B12 is probably a decent friend if one wants to get the intake valves just so, without jumping as far as a walnut blasting. Takes more time, more thoughtful process, but I've turned carbon on N18 engine injectors to floating soot with that stuff. FWIW.

 

Well, I may as well chime in, been a while. The 2017 F56 S (B46 engine) just rolled 150K miles.

I have not had any major work or non-maintenance part replacements done since upgrading the water pump (upgrade), replacing the thermostat ("while we were in there"), replacing the front crank seal (may or may not have been fine but let the shop do it since I had one and I had replaced the crank pulley), and replacing the counterbalance shaft plugs.

On the to-do list is to replace 1 or 2 of the coil electrical connectors (have had those sitting around for a while, so will do them when I standard-interval replace the plugs soon, and to replace the coils (at this mileage, may as well).

I have been continuing to watch the mystery oil seep, which I suspect is an issue with the casting of the oil pan itself, that finds its way down to the starter but never seems to actually damage anything. It has neither gotten worse nor better, still registers as annoying, and will probably lead me to replace the oil pan whenever I decide I'm up for the get-it-right-particulars of sealing it (it uses an RTV seal, not a gasket, and I haven't messed with that kind of instead-of-gasket thing before).

I have noted that if I get to 7.5-8K miles without an oil change, I will get yelped at about the oil level hitting MIN, and adding oil to make it happy... doesn't last long. Note that in general I do oil changes at 5K but 2x I have gotten a bit lazy, so noting for group knowledge that both times I have gotten lazy, I have run into this. The oil seep is a contributor by definition, but I don't think its the fundamental cause. Random FYI.

Also of note, the Bremmen Parts plastic oil filter housing I put in at ~100K miles now has 50K miles on it. No signs of trouble. No shade against the aluminum housings, I have the Bremmen plastic model because ECS did not have the aluminum one in stock back then (March 2023) and the aluminum aftermarket options were not in wide distribution at the time in general.

I have now done ATF changes 3x. Original was at ~95K miles, did the next at ~115K miles (15K mile interval) and the last at ~146.5K miles (30K mile interval). Happy with the condition of the ATF I am seeing at change time now, noting that ~2.7 quarts is all that will come out of the transmission each time. Planning to keep the 30K interval rather than getting more aggressive with it.

Aside from all that chatter and status update: it just runs. Still pulls like a champ. Fuel economy is not dropping (other than in response to me driving more assertively "for science," lol).