CastorTroy

I'm just finishing up some 100k maintenance on my 08 E550, and had a couple thoughts to share for anyone undertaking this adventure on an M272 or M273.

First observation: remove the SAI pump. It is 5 bolts and takes about 5 minutes, but gives you a lot more room to work and see. None of the walkthrough's I've seen suggest this, but I 100% recommend it.

Second observation: if your filter housing or oil cooler have been leaking for a long time, just get a new one. It's only $95 for an OEM housing, and you wont have to spend an hour or two trying to clean the caked on oil off of your old one.

Third observation: if you're going to get in there, replace EVERYTHING as it likely hasn't been done before. Thermostat, cam sensors, cam magnets, power steering fluid reservoir, serpentine belt, tensioner and idler pulleys. These are all wear items, and are very easy to do.

Fourth observation: as with all jobs, make sure you have all the tools you need BEFORE you start. The P/S reservoir screws require a mid length T30 torx bit or torx key. A standard T30 torx socket is too short to reach the captured screws, and my extended reach torx sockets are too long and run into the fan shroud. They would probably work on a V6, but they are a no go on the V8.

I've no idea how long this thing had been leaking, but it had been a while