Originally Posted by jzchen
I actually have both. My N54 didn't have an oil cooler and I retrofitted it. My wife's N51 doesn't. They both seem to be the same. I will try to verify when I get the chance. (I actually took a picture of the inside of my wife's when I did an oil change for her two days ago remembering this thread. The part number is 67 402 30 310. On top is Al Si9Cu3(FE). I am trying to attach a picture. If you do a retrofit buy 3 replacement bolts for the 3 that mount it, to the whatever you call it. In another thread I think I called it the block and someone corrected me. I forget what it is exactly. Anyways, I recommend it, because it seems to be an Aluminum part and most likely uses Aluminum bolts which are one time use: "Al"uminum "Si"licon Cu (Copper) FE (Iron? I'm not sure why the E is capitalized. I could be wrong on this one.) It's worth saving the headache of possibly having to change the gasket from a leak issue later. Then you might wonder maybe I should have changed those 3 bolts for a few dollars... If you do a retrofit if I remember correctly you should be able to torque each fastener to spec with a torque wrench. I think I used a 3/8 inch size.) When you do a retrofit, you have to change the oil filter housing...
Ohh I was unaware that some come without the oil cooler. I didn't realize you can retrofit it but now I wonder is it worth it or not. Have you tried to retro fit it on the n51?