Repair Mini Cooper Oil Filter Housing Coolant Leak

Learn 3 common Mini coolant leaks and follow along as I fix an odd one stemming from a broken oil filter housing gasket on a 2012 R56 Mini Cooper S. Video details the order in which to reinstall. Step by step procedure below.

Compatibility: Similar procedure should apply to all R56 and R57 Mini Coopers (2006 to 2012) but will be easier for the non-S models without a turbo.

Robb’s DIY Rating on 1 (easy) to 5 (hardest) Scale: I give it a 4. Nothing is easy to access in this engine bay, and it takes time and patience to remove and (worse) reinstall the heat shields, down pipe, and hoses to get to the oil filter housing.

Step by Step (with Tools Needed):
1. For Cooper S (check for other models), buy oil filter housing gaskets (Mahle B32690), oil cooler gaskets (Elring 375640), oil feed line from engine to turbo (Uro Parts 11657534454), oil return line from turbo to engine (Dorman 625826), coolant hose from electric/auxiliary water pump to oil cooler (Rein TCH0190), coolant hose from auxiliary water pump to turbo (Rein TCH0190 with new crush washers), 2 banjo bolts and 4 crush washers for oil feed line (this is a MUST, oil WILL leak if you don’t), studs/washers/nuts and gasket to mount down pipe to turbo (Elring 376340), oil (5 qt Castrol Edge 5w-30), oil filter (Wix 57512), and coolant (1 gal pre-mix Zerex G48 blue)
2. Lift car and secure on jack stands
3. Disconnect battery (you will have sparks when removing heat shields if you don’t) and drain oil and coolant
4. Remove coolant reservoir using 10mm socket and hose clamp pliers and install new oil filter using 27mm oil filter socket
5. Disconnect O2 sensor on top of down pipe (catalytic converter) using 21mm open end wrench
6. Remove top heat shield using combination of 10mm sockets and open end wrenches (6 bolts total)
7. From underneath, disconnect O2 sensor on bottom of down pipe using 21mm open end wrench
8. Remove bottom heat shield using 10mm socket (4 bolts total)
9. Disconnect exhaust and bottom of down pipe using 13mm socket (1 bolt for exhaust pipe, 2 nuts for down pipe)
10. From above, disconnect down pipe from turbo using 13mm deep sockets with extensions and universals joints (3 nuts and studs)
11. From underneath, disconnect bottom of turbo support bracket using 13mm socket (1 nut) and pry bracket away from heat shield
12. Remove heat shield using 10mm socket (2 bolts toward top of heat shield) and slowly pull down
13. Remove auxiliary water pump hoses using hose clamp pliers and 19mm socket on banjo bolt of hose connected to turbo
14. Remove oil return line using 8mm socket with several long extensions (1 bolt) and hose clamp pliers
15. Remove oil feed line banjo bolts using 17mm socket (1 bolt on engine block, 1 bolt on turbo) and make sure crash washers come off and don’t stick to engine block
16. Remove oil cooler using T30 torx socket (5 bolts total) and be prepared for some oil and coolant leakage
17. Remove oil filter housing using 8mm socket (4 bolts total) and be prepared for more oil and coolant leakage.
18. Clean engine block, oil filter housing, and oil cooler surfaces with light scouring pad and rubbing alcohol before installing new gaskets
19. Install new parts in order recommended in video (close to reverse order but some nuances), be sure to hand tighten oil filter housing and oil cooler bolts (consider Locktight and don’t over tighten since they’re aluminum), torque banjo bolts to 45nm, torque down pipe nuts to 55nm, and don’t forget to fill oil and coolant (including proper coolant bleed) or reconnect battery
20. Bonus: Wait to install down pipe and its top and bottom heat shields until you run the car a bit and check for leaks. It will be loud and run a little rough without the O2 sensors in, but the heat shields take time to install so better to check for leaks at this point instead of finding one after you’ve reinstalled the down pipe and heat shields.