2016 Mini Cooper S (Turbo). 124k miles. Adult driven, never raced or abused. Good maintenance history.

This is my cousin's vehicle. She got a light saying the oil was low. I tried to check it, but no dipstick. I tried the information area and it would only load to 15% and then "glitched" and went back to the previous screen. I tried like 20 times to get it to tell me the oil level. I wait until it was warmed up as well, as it wouldn't let me even start the test until it was warmed up (beyond dumb design as you could literally be causing engine damage waiting for it to warm up if the oil is too low).

Anyways, I tried like 20 times to get the oil level to no avail.

So having previously been a mechanic earlier in life, I figured no way this thing would shoot her an alert until it's outside of the "acceptable range" (minimum to maximum oil level), which is almost always 1 quart difference.

So I just went ahead and poured exactly half a quart of Mobile 0w20 in the engine, and called it good.

The oil warning went away.

Then shortly later, the engine started shaking.

So we took it to O'Reilly's Auto and had them scan the computer codes.

Misfire on cylinder #2 and #3.

Ok, it's got 124k miles and never had a tune up. No big deal, I'll swap the spark plugs. Bought four iridium spark plugs and swapped them all, as well as put a dab of dielectric grease on each coil tip and the plug to the wiring harness.

Started it up, still missing and shaking.

No problem, luckily I bought two Bosch ignition coils just in case this happens.

Swapped these on the #2 and #3 cylinder. Put a dab of dielectric grease on them as well.

Started it back up, it's still misfiring exactly the same and shaking.

This car is starting to get on my nerves.

Anyone have any ideas?

I thought for a second, that maybe the oil capacity was over and soaked the #2 and #3 spark plugs, but when I pulled them out, they were not wet with oil or fouled. I did notice some increased "burning" look on the #2 cylinder spark plug compared to the others, and the #3 was a little worse than #1 and #4.

I just don't think half a quart of oil with a low oil warning, over filled the engine capacity. Furthermore I've added over half a quart of oil before to many other engines, including small 4 cylinder engines, and half a quart is never enough to cause a problem. I specifically did this by the way in the past on high mileage vehicles that were burning a little oil and it was a females vehicle who I knew wouldn't add oil anytime soon so better to overfill it a little by half a quart.

Anyways, I'm at a loss as I've never had a misfire not be fixed after replacing the spark plugs, and ignition coils, especially if you used a little dielectric grease to ensure the connection.

I know nothing about Mini Coopers so I need some ideas please.

 

Let me add some information here that I just found out. Apparently my cousin informed me that this vehicle recently had a cracked head. She is not sure what the dealership did, but it was a "quick", and "inexpensive" repair. I suspect they poured something like blue Devil in the coolant to attempt to repair the head. This explains why I saw a little rust on the #2 and #3 cylinder spark plugs.

I have a feeling the fact that the two cylinders that have rust on the spark plugs, is not a coincidence that they are the two cylinders misfiring....

 

I doubt your oil addition has created the misfire issue, just a coincidence, IMHO. Strange it can't perform a complete oil level check, but I get your view on the no dipstick design.

How the heck did they determine it was a cracked head?? Where is the crack located and what has it opened up (i.e.- coolant, oil, cylinder to cylinder, etc)?? I would be very wary of the 'quick/inexpensive' repair and what it really did. You could swap the 1/4 coil packs with the 2/3 coil packs to see if the misfire follows the coil packs. I would do a quick compression check to see what you find, since I guess there could be a path between cylinder 2 & 3, which would show immediately in a compression check. From there a bleed-down test would be next to assess the health of that engine at this point.

 

So unfortunately this is a female I'm dealing with, and she was incorrect about the cracked head as well. I looked at the actual repair paperwork and the oil filter gasket failed. Apparently this is somewhat common, and requires the whole front of the car to be taken apart to get to it. I watched multiple videos on YouTube on it and it's a nightmare. Makes sense why they charged her $1,100.

Here are some videos:



Anyways, none of that should have anything to do with the miss. What's weird is that it never had a miss before, and then suddenly it has a miss on not just one, but TWO cylinders. Just seems a little too coincidental. I've never seen two misfires pop up literally at the exact same time. Regardless, not sure what else could cause them since the spark plugs and coils have been replaced. I could chalk it up to maybe I got unlucky and got a bad brand new part out of the box, but I replaced TWO coils, so both would have to be bad out of the box, as I still have two misfires. I highly doubt two Bosch coils were bad. Maybe some cheap Chinese brand, but not Bosch. Maybe the computer is causing something????

 

Ugg, so the 2016 MCS needs a lot more dismantling to get to the oil filter housing...glad my F54 has a bit more room. The $1,100 cost does make sense if you need to pull the nose off the car. My thought, if the filter housing dumped the coolant, that engine could have had an overheating cycle depending on how long it ran after the failure/dump. My guess is the mechanic noted that overheating the engine can lead to a cracked head. In any case, that would lead me to do a compression and possibly a leak-down test on the engine to see if it has indeed compromised the head gasket between cylinders 2 & 3. I agree that getting two bad coils is a long-shot.