DIY Disclaimer: I hold no responsibility should anything goes wrong when you decided to follow my guide. It’s strictly meant as a reference for knowledge sharing purposes.
2007 BMW E90 N46B20
Mileage: 85k km
Been noticing the roundel is losing engine oil and noticeable around the base of oil filter housing. There are 2 gaskets as shown in diagram below, item 5 and 6.
It is very interesting to discover that my car don’t have item 9 and 10.
These are the gaskets I bought.. RM15(Gasket: 11 42 7 508 970) and RM23 (Profile-gasket: 11 42 7 508 971), respectively.
Okay, here goes the DIY procedure..
1. Open item 13 (intake manifold), unplug connector (item 17), followed by removing item 1 (intake silencer).
Note: Item 9 will be stuck to item 13 while item 11 and 8 will be stuck to item 1. 
2. Unplug connector item 4 below. Open the throttle housing assembly: 13 54 1 439 580, item 3 below is a size 10 bolt and there are 4 to open, all similar size and length.
3. Lay old news paper to cover the alternator and whatever expose area that’s vulnerable to oil drip when we dismantle the oil filter housing and coolant heat exchanger.
4. Remove all 4 Torx bolts (item 7) securing the heat exchanger. All same size.
5. Now we unscrew the 3 size 10 bolts securing the base of the oil filter housing.
6. Replace the 2 rubber gaskets. Photo below shows I’m digging the oil filter housing bottom gasket.. notice how flat is the gasket? The heat exchanger gasket has be replaced in the photo, notice the difference in rubber surface texture? 
The old gasket is harden and brittle.. proceed with caution if you want to remove it in one complete piece. 
New gasket..
7. Clean the 2 connecting surfaces and install everything back in reverse order.
That’s all folks! 
My supervisor paying close attention while the job is performed.. 
Thank you for reading and please provide feedback or query if any.
Next job should be valve cover gasket.. really.. 
