Alright, hedging my bets and purchased an OES, MINI-stamped new replacement expansion tank. Looking at the thing, it's not molded consistently, meaning the center seam alone is uneven (seam grows from no gap to 1/8"+ gap) . This makes me a little nervous, but am wondering if I might just be over-reacting. But my initial thinking is...I'd rather risk the original tank (now 7 years old and no issues...yet) instead of installing the new one.

Somebody talk me off the ledge. Pics are attached, but those don't do justice in revealing the new tank "flaws".

Thanks!
Greg

 

Pretty amazed yours lasted 7 years.
Mine lasted no more then 3.5 years.

Personally, I wish I had just invested so I wouldn't have to worry about the seam splitting again. Plus that black tin just looks so nice.
I didn't notice any uneven seams on mine but it was already on the car and I had it all replaced at a shop and they disposed of it so I can't tell you if that's what caused it or not to be honest. Sorry.

 

We don't recommend the OEM tanks. Even the new ones from MINI fail as I've seen 4 this year fail that were all less than a year old. We recommend the Aluminum tank that way it won't leak.
http://www.waymotorworks.com/polishe...-tank-r53.html

 

I put a new oem one on three months ago and it already failed. I will be purchasing an aluminum one soon.

 

I'd be mighty unhappy if I installed the new OEM tank only to have it split quickly. How can BMW engineer such a "fine" piece of necessary equipment, not just with MINIs, but will various models?

 

Mine lasted 10 years, although it had only 45k on it. I bought a new one at the dealer for $70 including the cap. I checked the seams and didn't see any obvious leaks so it might of just been the cap.
You can understand why these fail, just check and see how hot they get with your hand.

 

My BMP Designs aluminum coolant tank arrived today. $120 without cap (uses eom cap). My eom plastic tank has not showed signs of leak yet but car is turning 10 next year and I do not want to take a chance

 

Speaking of taking chances......i would not be putting a ten year old cap on a brand new tank. JMO