I just did this today, I was getting a 1 second rattle on pretty much all cold starts where the X sat for more than a few hours. My X has 108,XXX on the clock. Keep in mind, i'm not sure yet if this will fix the issue, but i'll know in a few days and i'll update. I just wanted to get a writeup out there for the M62b46 specifically since most seemed to be for the M62b44.

Tools needed:
19mm socket
10mm socket
nut driver
ratchet
breaker bar - maybe (you probably don't need this, i didn't)
screw driver
pliers
paper towel/rag you don't mind getting oily.
Chain tensioner: 11317531813, i got it from autohausaz for $53 with free shipping
Time: 30 minutes

1) Pull off the 4 plastic fasters that keep the air intake on top of the radiator and disconnect the tube from the airbox (I disconnected it where the tube connects to the air intake, not where it connects to the airbox, as that will come out when you unbolt the airbox itself).

2) Unhook the secondary air pump hose that goes to the airbox cover (press in on the sides, slide out towards the front), undo the clips holding the cover on to the airbox base, undo the two clips that hold the MAF to the airbox cover. I didn't unplug the MAF as it didn't seem to get in the way. Remove the airbox cover, and the air filter.

3) Use the 10mm socket and remove the single bolt holding the airbox bottom to the chassis, on the passenger side of the airbox. With that out, you can just sort of wiggle the bottom up and around. Since there looks to be a vacuum line hooked up still, just flip the air box bottom over towards the driver side and let it rest on top of the intake tubing after the MAF.

4) At this point, everything is done by touch and you need smallish hands to get to where the tensioner is. First, place a piece of cardboard or something to catch spillage of oil under the passenger side of the X, it doesn't leak much, but i'm pretty sure there's no way to catch all the oil that will spill out when you take the tensioner out. Then put a rag or paper towel down on top of the lower A/C lines, be sure to get it underneath the tensioner head, so you actually catch some oil :-) When you look at the top of the passenger side of the engine block, the tensioner is just under that valve cover lip, between two A/C lines, nearly up at the front of the block. Because of how cramped it was though, I could barely see it and honestly pictures were pointless...although i'm thinking now i should have tried harder at least. If you want pics, I can disassemble again and grab them.

5) I used my 19mm socket and 3/8 ratchet and it was just enough clearance to undo the tensioner bolt. It took a bit of force, but a nice even, constant pressure pull on it released it. Once broken free, you should be able to get your hand in there and unscrew it. When you remove it, make sure you get both halves. Clean up as much oil as you can see. As a frame of reference, my old tensioner was about 1/4" shorter than the new one and had noticeably less spring tension.

6) I was able to install the new tensioner without compressing it first, your mileage may vary. Once again, by feel, guide the new assembly in, until the tensioner bolt was up against the block. Turn it reverse (like you're loosening it) for at least a half turn, preferably a full turn, this will seat the threads so you don't have to worry about cross threading. You'll need to be applying some pressure to it at this point obviously since the new tensioner has been released. You should be able to pretty much hand tighten it all the way. Get your 19mm socket back in there and snug it up, i couldn't find a good torque value anywhere, most people just said "snug it up". i'd say mine got nice and "snug" after about another 1/4 turn, maybe a little less.

7) Put your air box etc back together. When you fire it up for the first time it'll be a horrific noise for about 1 - 2 seconds while the new tensioner fills with oil etc. But after that, it should be smooth sailing. I had some residual ticks that went away after I brought the rev's up to about 2 - 2.5k. After that, she was quiet. I let her idle for a few minutes, checked under her to make sure there was no more leaking.

That's how I did it...I will update in a few days on whether or not it solved my rattle at startup. Hope this helps someone in the future who's on the fence about doing it.

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