I Dropped The ENTIRE DRIVETRAIN Out Of My Twin Turbo BMW

Ajouté : 2026-05-10

[00:00:00]This is the biggest project I've ever taken on. Oh my. I'm dropping the engine, transmission, and front subframe out from the bottom of my 2008 BMW 335i while it's all still connected together.

[00:00:13]Then I have to separate the transmission, tear down the original N54 that's filled with metal, pick it out of the subframe, transfer every usable component onto a fresh twin turbo N54, rebuild it with new turbos, lines, injectors, gaskets, and somehow get the entire drivetrain back into the car from the bottom up. But before any of that can happen, we've got to get this drivetrain ready to come down. So sit back, relax, grab a cold beverage, and let's get cracking.

[00:00:52]All right, let's DC the battery and dump some fluids. I'm just pulling the ground. What we need to do. Then I'm going to take a pocket screwdriver and flip the lock back over. Now the trunk won't shut until I manually hit the switch and open the actuator back up. All right, time to pull as much fluid as we can.

[00:01:14]That's going to take too long. Need my sucky hose. Found it.

[00:01:21]So, the game plan is we're going to dump the subframe out from the bottom. So, we need to drain all the fluids, drain the exhaust, start separating the subframe, pull the fan shroud.

[00:01:32]Does this thing have a little bolt?

[00:01:34]Let's knock out the bolt for the fan shroud. Pull the auto transcooler off the electric fan. Pop the charge pipe off of the electric fan. Pull the Torx out of the corner of the E fan.

[00:01:50]Let's get the oil out of this thing.

[00:01:56]Let's check out this oil filter.

[00:02:01]This filter only has like 30 minutes, maybe 10 miles on it total. I haven't driven this car since it started knocking. And for you, for those of you that are new to this channel, I'm replacing this thing because this engine developed a rod, some sort of internal knock. I cut the filter open. It was filled with filled with glitter. I haven't discovered the cause of the engine failure yet, but we will when we tear it down after I get the old engine out. I highly recommend you do this on all your oil changes. Just cut your oil filter open. Especially if you have an N20 engine, an N55, an S65, an S85, engines that are prone to rod bearing failure.

[00:02:39]That's a piece of Yeah, that's like silicone or something.

[00:02:45]Not seeing anything really shiny in here, but for context, this is the filter that I took out of it. Absolutely smoked. So, I I know this engine is done. This engine is done. So, or it will be in the next 100 miles.

[00:03:06]Look at that magnetic drain plug. That thing is loaded with metal.

[00:03:18]We're going to drop the subframe with the uh transmission still connected to the engine. So, let's start getting access to the drive shaft.

[00:03:27]The flex disc looks pretty healthy.

[00:03:30]Maybe a tiny little micro crack there. I think we can get one overnighted. Center support bearing looks really healthy.

[00:03:36]And then I forget if we got to bust this nut loose to get this rear out. I might just drop it and then bungee cord it over against the lift arm. But either way, we're going to yink this flex disc and drive shaft out of there. Let's get this drain plug back in.

[00:03:52]So, for those of you that don't know really what it means to drop the subframe out from the bottom with the engine, we're going to disconnect the control arms from the knuckles or disconnect the control arms from the subframe. We're going to literally support the engine and transmission and subframe from the bottom and lift the car off of it. That way, I can pick the old engine out of the subframe, pick the new engine back into the subframe, and then lift it back up into the vehicle.

[00:04:18]I've never done this by myself before, so we're going to figure it out. Seemed like the most logical way to do this, though, because I can install the turbochargers onto the engine with the engine out of the vehicle. While we're down there, let's get this strut brace off.

[00:04:34]So, we need to disconnect everything engine from the body, which means coolant hoses going to radiator. The automatic trans thermostat can stay because it's right here. As long as we have the coolant hose to the radiator disconnected, we're okay. We need to disconnect the two charge lines for the intercooler by popping these two clamps.

[00:04:55]Popping those out. I'm going to see if I can get this intercooler popped out from the bottom real quick cuz it'll just make things a little more simple. Give me a little bit more room up here in the front end.

[00:05:09]Oh, that's so much dirt. Look at all that junk.

[00:05:14]Project this big, you got to keep organized and stay clean. Need to use cups or plastic bags. Organize all your nuts and bolts so you know where everything goes. More organized and clean you are, the smoother everything will be. Poor preparation makes piss poor performance. Let's make some more progress up top. I'm just going to keep popping top, bottom, top, bottom, and just not following any guide. I'm just trying to do what makes sense. We're going to be able to leave a lot of stuff connected though. Like I think I'll be able to disconnect the wiring harness from the Ebox and drop this whole thing with the wiring harness connected.

[00:05:49]See how much coolant we can get out of this bottle. Then we'll also pull pull the coolant reservoir, pull these vacuum reservoirs, too, just to give ourselves some more room on the sides.

[00:06:02]Also, yesterday I went to a local shop and had them evacuate the AC system for me. So, there's no R134 in here because we're going to have to separate the compressor from the rest of the the engine. So, we're good on that front.

[00:06:16]Let's get this coolant bottle out of here.

[00:06:20]Coolant float sensor. And then we have a hose connection here at the bottom. I got a drip pan underneath cuz it's going to leak a little bit of coolant. Pop that guy off with the pry bar.

[00:06:35]Look at all that room we got over there now. All right, we can pop the upper radiator hose and the lower radiator hose now. Now, there's three ways that you can pull an engine. You can drop the trans and pick the engine out from the engine bay, but you need to have adequate room in front of the car while it's on jack stands or a lift to get your cherry picker in there. You can pick the engine and the trans out together through the front, but again, you have uh room limitations. And then three, you can drop the subframe out from the bottom. You don't have to worry about as much room in front of the bumper as you do with the other methods, but you need to have a hydraulic lift table or be able to get the car high enough to adequately get it out. Because this engine is turbocharged and I'm going to put the turbochargers on before I put the engine in. Putting it in from the bottom is a my best move here. Now, looking at this engine bay, if I were to drop it out from the bottom, this charge pipe here going to the throttle body is going to hit the inside of this fender well. So, let's take off these diverter valves here and pull this charge pipe from throttle body to intercooler.

[00:07:37]And then the other side of this is the other end that we disconnected at the intercooler. Going to have to pull the power steering system, too. We're going to have to drain that because power steering system connects to a power steering cooler over by the radiator.

[00:07:49]Then this hose runs down to the pump.

[00:07:51]So, I think we'll disconnect it at the cooler. That way, we don't have to disturb that power steering pump hose connection. And I think everything here in the back can just fall away. We also have this line here that goes from AC compressor to evaporator. So I have to pull that there. And then this one is the service port. I'm just going to slowly keep picking our way through.

[00:08:13]Let's get our second coolant hose pulled off here. Our lower radiator hose.

[00:08:22]Then we'll go down below and pop that off the thermostat just to give ourselves some more room in the front.

[00:08:28]The hot side to the intercooler can stay. I think we have room to dump that out with the engine. See if I can get that water pump hose from the bottom right quick.

[00:08:43]Got it.

[00:08:46]All right. Another coolant hose down here that goes just below the lower radiator hose.

[00:08:53]And then all that seems pretty dry.

[00:08:56]We're all disconnected over there. Did you get it, Sage?

[00:09:01]Sage is chasing flies.

[00:09:04]Where is it?

[00:09:08]Where is it? Go get him. Go get him. And then one last coolant hose attaching us to the radiator. And that is here on the auto transcooler. It's disconnected on the transcooler side. All right, with that deceedded, the cooling system in the front end is completely disconnected. We still have some power steering. Let's do this power steering hose while we're here, too.

[00:09:33]Problem is that collar there for that power steering hose is popped out. Hope it still works or it's going to be difficult. I bought a tool for this BMW power steering hose trans oil cooler line. disconnect tool. So, you just slip it over the quick connect and it depresses it for you.

[00:09:51]Wow, what a beautiful tool. That worked wonderfully. Let's drain out all that CHF11S.

[00:09:58]I think it wouldn't be a bad idea for us to disconnect it at the power steering pump. I don't know, maybe just disconnect it at the bottle. That way, we don't have to take the whole bottle with it. So, I'm just going to try to disconnect this hose from the power steering bottle. And then um we'll just sort of zip tie this hose over to the side of the engine and just let it hang out over there while we drop it.

[00:10:22]Okay, we'll get this brake booster vacuum hose just tucked out of the way.

[00:10:26]And then let's pull these strut braces and then disconnect this AC line.

[00:10:36]All right, let's pop this AC line off.

[00:10:39]This is compressor to expansion valve which goes into firewall.

[00:10:44]There's going to be a little bit of pressure in there and that's because I had it evacuated but there's still some dye in the system and I drove it yesterday so the compressor.

[00:10:55]There we go. The compressor put a little pressure in the system. Put a paper towel in there. Keep it clean. And then this little service port here is also attached to that hose. Let's pop this clip off. And then this AC hose and the service port can drop with the engine.

[00:11:13]Then there's another heater hose here.

[00:11:16]Ah, got it. It's that hard pipe connection. So, we'll need to pop that hose, too. This one here.

[00:11:22]Yeah, that goes to that hard pipe that runs across the subframe. I can reach it right now.

[00:11:30]Got it. We still need to disconnect the steering column down to the rack and pinion at the subframe. And then we also need to go over here to the Ebox. See if we can get the harnesses disconnected.

[00:11:42]Let's mess around with this for a little bit. Slide the locks.

[00:11:48]All right. So, we got one harness here, one harness here with the ground, another harness here that has the power.

[00:11:56]Then we need to disconnect the charging cable for the alternator.

[00:12:00]Then I'm just going to put these nuts back on here. Cover this up. Pop this ground strap over here by the washer.

[00:12:08]And then we're going to start disconnecting these harnesses. Luckily, everything's pretty keyed, so it's pretty impossible to mix it up. Another thought, too, is I could remove the entire Ebox.

[00:12:20]Let's just unplug.

[00:12:26]If I can get this piece of this harness out, I can take this whole DME and flop it over. This is my only my only part where I'm getting stuck. If I can get this latch off of this DME connector.

[00:12:40]Okay, tire harness is disconnected there.

[00:12:44]Never done that before. All right, we got another AC line we need to disconnect down here.

[00:12:53]This is overwhelming. This is a lot, but I believe in myself. I can do this.

[00:12:59]Now, we need to pop this oil cooler off.

[00:13:02]Let's get more caffeinated.

[00:13:05]I think it's an Allen. No, it's a 13.

[00:13:08]Because the oil cooler bolts into the fender well, we got to DC these oil cooler lines here.

[00:13:14]We're going to be replacing the oil cooler, too, because it's filled with metal. We don't want to put all that new metal into our new engine. It's guaranteed way to ruin our new engine is to reuse the oil cooler and try to flush it. There's just no way we can realistically flush it well enough. I got some used oil cooler lines we're going to swap into. All right, let's go up and start working on drive shaft suspension.

[00:13:46]Ah, it's not neutral. It's okay. I know a hack. Bust the shift selector loose.

[00:13:52]Bust this 13 loose. Park reverse.

[00:13:57]Neutral.

[00:14:00]Okay, time to release the center support bearing. I'm going to mark where the center support bearing is mounting to the unibody so I can get the position when I reinstall it.

[00:14:16]All right, I think we can just like bungee it. Yeah, we should bungee it up to the side. I don't want to bust that rear CV joint loose if I don't have to.

[00:14:25]I don't want to disturb it.

[00:14:29]That's nice right there. All right. Now, I need to do sway bar links and sway bar control arms, steering column, and then fuel line. I think I also need to do EVVAP up to the purge valve.

[00:14:45]So, do this one, this one, plus ride height sensor.

[00:14:53]Okay, those will swing to the front. Oh, we got to do tie rods, too.

[00:14:59]I probably should have pulled the wheels first. Tie rods out, wheels off.

[00:15:06]Getting this lower control arm out and then I'm putting disconnect this ride height sensor. Ah, come on.

[00:15:14]As long as the tie rod is underneath the control arms, it'll be able to drop out.

[00:15:18]Normally, I would bust the uh steering column loose from the bottom, but on this E90, it's pretty buried. I have pretty good access from the top. So, let's bring her back down. And then let's do fuel line, evap line, steering column.

[00:15:34]Right down there in the light, you can see the e torx bolt. That's what sandwiches the steering column to the rack. I'm going to get down there, rip that bolt out, separate that.

[00:15:43]Bolt is out. Okay, that's off. I need to make sure that that doesn't spin. And I got to remember not to spin the rack and pinion because the clock spring for the steering wheel controls can become out of sync of the rack and pinion. So that means when you turn it all the way to the lock, the steering wheel might not be synced up. That ribbon cable in there can snap. I'm going to take some masking tape here. Rope would probably be better, but this will be fine.

[00:16:10]This one right back here is the evap line from fuel tank up to the purge valve. So I'm going to get back there and DC that one. And you can just think of it as, you know, disconnecting every body system from the engine, right? Fuel tank, evap goes up to the purge valve.

[00:16:25]Now, we need to do fuel tank up to the um high-pressure pump. Now, the fitting for it is kind of buried under the intake manifold. I'm going to go up real quick and see if there's access for another soft line down underneath the unibody. If there's not one there, I'll pull the throttle body and pull that hose down there. Hoping there's a fuel line connection underneath here. How does this thing come off?

[00:16:52]Okay, fuel line there. EVVAP is still okay. We got that disconnected just fine. Future reference though, we could have done it there. All right, then we need to do fuel line here. Get our oil drain pan. Safety glasses are probably a good idea.

[00:17:09]Yeah, that was a good idea. Ooh, ground strap, too. If I were to uh turn the key on or put the key in the car, this thing's going to spray fuel. Even if you just open the door with the battery connected.

[00:17:22]So, drive shaft is disconnected. We're going to pull the transmission crossmember. Cats are going to come down with the subframe. It wouldn't be a bad idea to disconnect the O2 sensors here.

[00:17:35]Also do these lower bell housing bolts.

[00:17:38]Yeah, it'd be a good idea for us to like pop the oil level sensor, do these lower bell housing bolts cuz it'll be hard to do while the subframe is down on the hydraulic table. Trans lines can stay.

[00:17:51]O2 sensors. I should probably disconnect just in case. That way I can spin the O2 sensors out of the cats. These if we just tuck up. But yeah, fuel evap is good. Trans lines are staying on the car. That harness is going to go with engine mounts. We can disconnect once we get it down. Tie rods are disconnected.

[00:18:13]Control arms are disconnected here.

[00:18:15]We'll take the subframe bolts out. Oil cooler's DCD. Control arms are disconnected over here. Tie rods disconnected. Charge pipe's going to come straight down. Transcooler hose is DC there. Transcooler is going to come down with the subframe. Yeah, I think we're in good shape. So, let's do these bell housing bolts. I'll do this one, this one, and this one. These three, and then we'll be in good shape.

[00:18:42]We can do these bell housing bolts once we put the subframe back in the car.

[00:18:47]Okay, I should probably replace these bell housing bolts. I don't have these aluminum ones. All right, I think we're good, dude. Before I get under there with the lift table, I'm going to bust loose the trans crossmember. The engine can hold it up just fine.

[00:19:04]All right, we need to get this hydraulic lift table underneath and see how high it can get. Then we need to lower the subframe to match it. This is the first N54 engine I've ever removed. I've done Mini Coopers. I've done N55s. Actually, I only think I've done N55s for BMW engine. No, I've done a M62. That was in a shop. This is in my garage. See how high this thing will go. Let's get it lined up with the subframe.

[00:19:34]Had to modify this lift cart cuz normally the handle is fixed upright.

[00:19:39]Okay, that's how high it goes.

[00:19:42]M. It's going to be tight. I can crib it up so it catches the bell housing. And then once I bring it down, I'm going to have to uh put like a dolly with wheels underneath the trans crossmember to prop that up. Okay, I know roughly where it it's going to be. So, let's drop it down a little bit. Okay, we just need to go up and kind of see where it catches.

[00:20:07]All right, I think I'm going to block the center so it doesn't put stress on the oil pan.

[00:20:15]I can block this front here.

[00:20:19]I need a little thinner on this front block. Like 1 in 2x1.

[00:20:25]It's pretty perfect. Let's take out the subframe bolts, which look like 18s.

[00:20:32]We'll have to come down and see if the trans wants to hang and make it fall backwards.

[00:20:39]That should capture the bell housing if it wants to sag back. All right, moment of truth here.

[00:20:46]She's falling back a little bit, but I think it'll be okay.

[00:20:52]Okay, it's DC. Now, let's try to go up with the lift just a touch.

[00:20:59]Oh, shift linkage. Shifter cable. I'm not nervous. You're nervous.

[00:21:05]Woo. That shifter was holding it up. But that's okay. I needed to block up that rear more. But that's okay. I can fix that once I pick the engine off.

[00:21:19]I should release it from the front rather than the lift in the back. So, I can see.

[00:21:25]May or may not be pooping my pants right now. Looks clear up top.

[00:21:34]Oh my lord. We don't like that. Come on, lift.

[00:21:40]Don't be jumpy on me. We can't have that.

[00:21:50]That wasn't sketchy at all.

[00:21:55]We did it. We did it. We got the engine and trans out with the belt on and all the charge pipes and everything.

[00:22:08]Well, first thing I need to try to do is crib up this bell housing a little more.

[00:22:13]Get the weight more forward.

[00:22:18]Oh, that's perfect. Got that cribbed up with a 4x4 and a 2x4. We have really good capture on the 4x4 in the center.

[00:22:26]And we almost have capture here in the front. So, once we do pull the trans off, this thing will be able to settle forward and I'm sure it'll probably catch on this this 1x6 and this 4x4 combo. You know, I don't think I realized how much work this was going to be until I saw this entire E90 drivetrain sitting on my floor. But here we are, and there's no going back. In the next episode, the transmission's coming off. We're peeling off the entire wiring harness, and we're going to start picking apart this N54 piece by piece. I hope you enjoyed. I hope you learned something new. Subscribe so you don't miss the next episode, and I will see you on my next day off. Cheers.