I've read here that you should change the oil pressure sender around 100,000 miles since if it begins to leak, the oil will be contained within the plug and will invade the wiring harness causing all kinds of problems. With 212,000 miles on my 2004 S, I decided to fit another sender. I'm a professional mechanic/engineer and have changed out countless oil and water sending units over the past 60 years. Guess what? I cracked the aluminum oil filter housing that the sender threads into! And, it didn't even seem tight, just snug. Cost of a new housing: $450 plus tax!!! Holy crap! Does Mini think we all own Bentleys as well as the Mini? While I could remove the housing and try to Tig weld up the crack, I'm not comfortable trusting my motor to a repair like that. Ordered a new housing for nearly $500 after tax and shipping. What a horrible design to be so fragile.

Lesson here: be VERY careful tightening the new sender. In hindsight, I should have counted the number of turns to remove the old sender and use that number to install the new one. Live and learn. On my second $969 exhaust header as well due to failing flex couplings. Companies must be buying their couplings from China. Love the car and hate it at the same time!

 

Thanks for the warning --- I've seen the photos of oil in the harness you speak of it and it is a horrifying sight. What a major bummer that in the process of preventative maintenance such a thing occurs. Torque for it is 15 lbs/ft but it seems like a tight spot to even use a torque wrench there in situ.

I can totally relate to the love/hate thing because many times I've felt like I'm being punished LOL but then such a massive reward in driving experience and I'm head-over-heels again.

And BMW MINI parts pricing is definitely absurd and causes much pain in the wallet, although I consider myself somewhat lucky that my local dealer tends to have better pricing than average and it's easy for me to drive by to pick up.

Was this the part # you bought?

https://parts.miniofkennesaw.com/oem...ng-11427562250



Not much cheaper really, but every little bit helps.

Very curious to hear what brand of headers failed on you if you'd care to share.

 

Yes, that's the part I ordered from Pelican Parts. I wanted to do a more detailed search but my lousy internet connection here in the countryside limits me to just 10GB per month (exorbitant overage charges, thanks Verizon!) and I was already at 9.9GB so had very limited amount of searching. I had some other small items I was ordering from Pelican as well so just bit the bullet and placed the order. Next time I'll be more diligent. The header that failed was the Flashpoint I bought from Way Motorworks. I had it on for about 3 years when the flex joint failed causing a loud exhaust leak from there. I originally removed the exhaust and welded in a replacement flex joint. Unfortunately, the cheap Amazon coupling failed within 6 months. So, I again removed the header and welded in another Amazon coupling which fell apart as I was installing the exhaust!! Love that Chinese crap they're selling these days. Ordered the more expensive Milltek header and cat from Way Motorworks and it looks to be very good quality. I had just installed it when I decided to replace the oil sender since I had the header heat shielding removed giving slightly better access. Concerning the torque value: you're correct in that there isn't room down there to fit a torque wrench. I was using a stubby little 3/8" drive to limit the amount of force I could place on the sender but it didn't work. Now I have to drain the coolant and remove the entire filter/cooler housing to solve the problem. Only good thing is the new housing comes with the oil sender already installed so there's no risk of a repeat disaster.

 

I added a fitting so I could install an actual gauge in my R53.
While I did snug it pretty good, I was careful putting that big fitting into the filter housing. Now...I'm glad I was careful.
The fitting is pretty big and bulky. (read that...heavy). I cut as much weight from it as I could so it would put less stress on the filter housing.

Mike