I have an 2008 128i that is past it's 15yr/150k mile SULEV warranty. It popped up the P0143E/2AD8 code, which related to the EAC sensor going bad. Now, BMW's only option to fix this code is a $500 OEM radiator. Here is how I went around it.
Part 1: I describe my problem, and show you how the EAC sensor comes off the stock radiator.
Part 2: I install a new EAC sensor using the proper procedure (I followed ALLDATA). So far, no new codes after a couple drives.
Sensor part number I used was: Mercedes 2219055600. There are other sensors available, which supersede this part number.
Glue I used: Palm Adhesives 155 LT, an alternative to Loctite 4204
If replacing the entire radiator too, purchase the CSF 3718 radiator. You will still be cheaper than the OEM BMW unit, and have a refreshed cooling system. This is the only aftermarket radiator that has the block for the EAC sensor.