Having undertaken this job last weekend, thought I'd share with you all how I went about doing it & I hope this will assist anyone else who finds themselves in the same position as me & has thier turbo fail on them.
Firstly, a few points.
This is a purely a guide to how I did this. I take no responsibility for any damage caused to cars or people when attempting this!
This is based on an E91 320D (M47N2) with the Mitsubishi Turbo (part number 41935-05660), other models/varients may differ.
My shopping list is not comprehensive, it's what I chose to buy.
I can't remember the size of every nut, bolt & screw that was undone during this. I'll list those that I'm certain of & others what I "recall" them being.
You'll definately want an extra pair of hands during this, it's not a one person job.
So, let's get cracking!
Firstly, the shopping list.
A turbo (obviously).
I opted for a reconditioned unit from Turbo Technics in Northampton as having been around the modified car scene for a while, I've heard many good things about them. They weren't the cheapest I found but it's not wise to compromise when dealing with reconditioned turbos. This one cost £510 but you will get £90 back on return of the old unit making the cost £420. It also comes with a 24 month/24,000 mile warantee provided that certain fitting critera is met (see below).
Next, the oil feed/return pipes & gaskets/o-rings.
You must (at minimum) replace the oil feed pipe & o-rings when replacing the turbo as oil starvation is a common cause of failure. Not doing so will invalidate any warantee the replacement unit comes with.
I bought the lot,
Oil feed pipe - 11427791624
Oil Return pipe - 11427791632
Return Hose - 11427793065
Return pipe gasket - 11422246091
2 x o-rings for the oil feed pipe - 07119905041
The gasket for the turbo to manifold came with the turbo but the part number for that is - 11627795266
This lot came to £96.48
Lastly, the service parts required.
Oil & filters etc plus a large can of brake/clutch cleaner (the reason for this will become apparant later).
Total here was £83.70.
Now we can start taking things apart!
Firstly, loose the engine cover, the air intake & the rubber boot between them.
The engine cover is 2 x 5mm allen bolts & the intake is 3 x (T20 I think) torx screws.
You'll then have this.
Remove the engine undershield with the car raised (16 x 8mm hex screws I counted).
Next, drain the engine oil & replace the oil filter. I personally use engine flush which involves a 15-20 min fast idle before draining so if you do this, leave the car for 30 - 45 mins after draining the oil so the engine can cool. Turbos & the surrounding pipework will be HOT!
Once that's done & the sump plug is back in (don't refil with oil yet), get the car raised & on axle stands (safety first & all that).
Undo the 2 x 5mm allen screws from where the duct to the turbo connects to the MAF. The one on the top left is easy & the one on the bottom right needs a little "poking aroud" to get onto.
Once undone, pull the duct towards you & it'll pop off the turbo & the other rubber hose.
Next remove the pipe from the turbo to the intercooler. Undo but don't completely remove the top one & remove the lower one (I think one of these was a torx & the other was an allen), twist the ring on the end of the pipe anti-clockwise & pull it from the turbo.
Then remove the other end of the pipe from the intercooler. Prize the retaining clip outwards with a flat bladed screwdriver & pull the pipe out.
At this point, it's good practice to remove & clean out the intercooler. Depending on the severity of your turbo failure, it's likely that they will have a lot of oil in them so I'll cover that now.
First remove the plastic shield from beneath the radiator & intercooler by undoing the hex bolts on the metal brackets seen below.
Remove the pipe from the other end of the intercooler to the EGR (same style clips as the previous one). No photo here I'm afraid but there's an electrical connector to remove from the pipe & a small clip that secures the wire for it.
To remove the intercooler, remove the 2 x torx screws (T20 again I think) at either end that secure the intercooler to the radiator & pull the intercooler downwards to release it.
You'll now have this pile of filth!
Firstly remove all of the crud & dead insects from outside the intercooler with a soft brush & then (this is where the brake & clutch cleaner comes in), thorougly flush the intercooler & pipes out to remove all of the oil & soot etc. Basically pour it in, cover the ends, shake it all about & repeat until the cleaner starts coming out clean.
Back to the turbo now.
There's a clamp securing an air-con pipe to the side of the turbo, undo this (can't remember what size that was) & pull the pipe away from the turbo.
Next remove the oil feed pipe to the turbo from the side of the block (the Haynes manual say's remove it from the turbo but that's near impossible as we don't have the luxury of the engine sitting on a workbench). Using an extension bar, undo the clamp at the engine end of the feed pipe from the front of the block & then prise the pipe to the left so it pops out.
Remove the electrical connector to the turbo actuator by squeezing the sides & pulling it off.
We have reasonable access to the turbo now but no-where near enough so it's time to remove more covers!
Remove the pollen filter housing (6 x 8mm hex & a few clips at the front if I remember correctly).
Then the two covers either side for the brake fluid reservoir & the relay box & unclip the long black, rectangular unit (seen below) from the cover by pulling it forward.
Remove the electrical connector from the bonnet sensor on the nearside, twist & remove the sensor on the offside (by the brake fluid reservoir) & unclip all of the wiring so they are seperated from the cover.
You then need to remove the whole plastic cover. Remove the rubber seal that runs along the front of it, be aware that there is some of the washer hose clipped to it on the offside (also under it) so unclip those. Sorry, at this point I can't remember how many screws there were securing it but I'm pretty sure it was only a couple more 8mm hex. Easy to figure that out when you can see it!
Next remove the strut brace. Note that this in two halves & you'll need to remember which side is which!
At the turret ends, remove the torx bolts with a female bit & in the centre, remove the round plastic cover to the right of the wiper arm & remove the larger torx bolt from under that & withdraw the two halves of the strut brace.
Next, remove the air filter housing cover by undoing the (4 - 6 I think) 5mm allen bolts from around it.
Remove the air filter & you'll have a bit more room to play with.
A good time to clean out all the dead things from the air filter housing. Note the gardening glove in the above picture. You are working around the battery live boosting point so you can either disconnect the battery (recommended) or cover it like I did (your choice).
Back to turbo removal!
From under the car (this is awkward but dooable), undo the jubilee clip that secures the hose from the oil return pipe from the side of the sump. This can be done with either a stumpy screwdriver or a long flat blade that will reach by going over the front support beams from the rear. There's not much room for leverage under here & I couldn't pull the thing off the sump so as I'm replacing it anyway, I cut through it with a stanley knife. Photo's of this impossible lol!
While you're under there, you'll see the 13mm hex bolt that secures a mounting bracket to the underside of the turbo, remove this.
Next, remove the clamp that secures the dpf to the rear of the turbo. This requires a 6mm allen bit.
This is bloody awkward & the only way I found I could do it was from above with a couple of long extension bars & a universal joint before the holder with the 6mm allen bit in it.
Once you have this undone, remove the bolt from the clamp, remove the clamp & the dpf will separate from the rear of the turbo quite nicely.
As this point, the only thing now securing the turbo to the car is where it bolts to the exhaust manifold.
Remove the 3 rubber bungs from within the air filter housing.
Reach under that, unclip & remove the metal cover below the holes.
You will now see the 3 bolts that mounts the turbo to the exhaust manifold.
VERY IMORTANT! These are 12mm multipoint bolts, use multipoint socket NOT a hex socket on these or you will likely wreck them & find yourself in a whole world of trouble!
These are very, very tight & I had to use a short breaker bar to crack them first.
With someone supporting the turbo, remove all 3. The turbo can't drop far so once it's free, let it go & bin the gasket to the exhaust manifold.
The turbo is now free!
What you will note at this point though is although the turbo is free, it ain't going anywhere with that coolant hose in front of it! You'll need to remove the clip on the large hose & the jubilee clip on the smaller one & move it out of the way (I secured it to the offside front corner of the engine bay with a cable tie).
You will loose coolant at this point so take whatever precautions necessary (I lost approximately 1.5 litres).
Now you can remove the broken turbo!!
Take a moment or two here to feel very smug!
When you've finished gloating over yourself, get the old & new turbos on a table together as it's time to attach the feed, return & hose (using new gaskets & o-rings of course) pipes to the new one.
This is pretty self explainatory when they're sitting in front of you. Just be aware to get the hoses all facing in the same directions on the new one as they were on the old one. An exploded diagram may be handy here.
As part of priming the new turbo, I also poured a little fresh engine oil into the oil feed at this point.
With an assistant, get it in the car!
I found it easiest to have a mate drop one of the bolts back down the hole in the top of the exhaust manifold & hold it in place with a socket & bar. I could then manipulate the new turbo onto it (with a new gasket of course), get one bolt finger tight & then get the turbo & gasket in the right place to get it mounted.
Get it tight & feel proud of yourself!
From the start to this point took me about 8 hours last Saturday so I called it a day & went for the refitting of everthing on the Sunday.
The Haynes manual phrase "refitting is a reversal of removal" is quite accurate here so I'm not going back through the whole thing again in reverse lol!
Note the following though;
Getting the clamp back on where the dpf meets the exhaust end of the turbo is a pig. It's just a case of getting your hand in there, fiddling with the clamp until it's over both the flange on the end of the dpf & the flange on the turbo & getting it done up. The flange on the end of the turbo is slighty convex & the flange on the end of the dpf is slightly concave so once they're together they do hold together. There is no gasket between them.
If your air filter is manky, replace it.
Get everthing back together (don't worry about all of the covers just yet as you may need to get access to things if anything is wrong), top up the lost coolant & refil the engine oil.
Do not connect the oil return pipe to the sump just yet as you need to prime the turbo first!
This is messy. You may find a better way of doing this, I can only post the way I did it & being that I was under the car with both hands in use there are no photo's.
Remove the fuel pump relay, this prevents the engine from starting when you hit the ignition.
Under the car, with one hand hold the oil return hose away from the pipe on the sump & with the other, hold a container of some sort under it (in my case, the bottom half of a chopped up squash bottle). Have an assistant crank the engine over a few times until about half a pint of oil has come through the return pipe from the turbo. Once done, fit the return hose to the sump pipe, secure the jubilee clip then get out from under the car & laugh about how much engine oil you are now covered in!
Before starting the engine again, refit the fuel pump relay & check that absolutely everything is back in place! Learn from my mistake here, I spent a further 4 days fretting as I was still getting no boost from the new turbo. It turned out that I hadn't connected the boost hose from the turbo to the intercooler properly so all of my new found boost pressure was escaping everywhere before getting as far as the inlet manifold. I cannot emphasize here how important it is to double check everything!
That's about it people. In a worse case scenario it may be necessary to also clean out the inlet manifold & exhaust but that depends entirely on the severity of the turbo failure. I didn't need to so I can't cover that!
Hope this helps anyone in the same position that I was in as this whole exercise took 2 days, cost just over £600 in all & compared to the £2k plus BMW would've wanted to do the job, it's well worth it!
I think I've covered it all, anything missed then sorry but I'm sure you'll figure it out while your doing it!