Figure 1 | | You don’t need to remove the compressor outlet hose at this point, but you can see here that I have. Note the oily discharge that has been building up for some time; this can be a symptom of a problem with the turbo, but in this case it appears to be simply the accumulation of oil through the crankcase ventilation system (which is directed into the intake tract just ahead of the turbocharger) over 100,000+ miles of service. The first step is to remove the support bracket between the turbocharger and the engine block. The support is the gray metal piece extending to the bottom of the center of the photo. On the turbocharger side you need to remove the 6mm Allen-head bolt seen in the center of the photo (22 ft-lb). | | Large Image | Extra-Large Image |
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Figure 2 | | On the engine block side of the support bracket, you’ll find an 8mm Allen-head bolt. It is slightly obscured by the turbocharger’s oil return tube, so you may need to use an L-shaped wrench on it. Or, you can disconnect the end of the tube at the turbocharger (which is the next step anyway), and that may give you the wiggle room you need to get at this bolt (18 ft-lb). | | Large Image | Extra-Large Image |
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Figure 3 | | The turbo’s oil return tube connects to the turbo with two 5mm Allen-head bolts; one of these is visible here, and the other is directly on the opposite side of the tube (7 ft-lb). It’s a good idea to remove the oil return tube completely and flush out the line using brake parts cleaner. This will remove any carbon starting to build up in the line. | | Large Image | Extra-Large Image |
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Figure 4 | | With the two bolts removed, the tube can be disconnected from the turbo. You should have a small drip of oil, but not much more than that. | | Large Image | Extra-Large Image |
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Figure 5 | | This gasket, which sits between the oil drain tube and the turbocharger, should be replaced during the reassembly process. | | Large Image | Extra-Large Image |
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Figure 6 | | Remove the hose that runs from the airbox to the intake side of the compressor by loosening the hose clamp and prying the hose loose. Looks like our turbocharger will need a bit of cleaning before we reinstall it. Just above the compressor inlet, on the turbocharger, you’ll see a 12mm banjo bolt for a pressure reference line that you’ll need to remove next. | | Large Image | Extra-Large Image |
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Figure 7 | | This photo shows the same 12mm banjo bolt, seen from above. It’s a bit hard to see but this photo should give you some reference for locating it. | | Large Image | Extra-Large Image |
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Figure 8 | | The next major step in the project is to remove the airbox, which contains the air filter. The airbox has many connections, both electrical and mechanical, that need to be disconnected in order to remove the airbox and open up access to the turbo and other surrounding components. Start by disconnecting the Evaporative Emissions (EVAP) purge regulator valve, which sits on top of the airbox, toward the rear. Pull up on the metal clip to release the connector… | | Large Image | Extra-Large Image |
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Figure 9 | | …and then pull the wiring away. Some cars will be equipped with a “Power Output Stage” connector, which would be located on top of the metal blanking plate that is visible just to the left of the screwdriver handle and beneath the wiring harness in this photo. Although the engine pictured here is coded as an ATW engine, many of these components correspond to the AWM code engine, at least as described in the Bentley manual. | | Large Image | Extra-Large Image |
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Figure 10 | | The connector for the wastegate bypass regulator valve is next, but the procedure is the same, with one metal clip to release. This one is located near the wastegate, just forward of the turbo itself. | | Large Image | Extra-Large Image |
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Figure 11 | |
Figure 12 | | Some cars, like this one, are equipped with a secondary air injection system, which is designed to alleviate start-up emissions. The system feeds air into the airbox up from the hose I’m holding in this photo, connected to the hard plastic tube just above my hand. Disconnect this hose. | | Large Image | Extra-Large Image |
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Figure 13 | |
Figure 14 | | Disconnect the two hoses seen here. The hose leading from the activated charcoal filter pictured here leads… | | Large Image | Extra-Large Image |
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Figure 15 | |
Figure 16 | | The last connection is the wiring for the MAF sensor. This is located under the round rubber plug on top of the airbox. Peel the plug back to gain access to the connector. | | Large Image | Extra-Large Image |
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Figure 17 | | Like many electrical connectors on this car, it is helpful to use a small flat-blade screwdriver to release the connector. This close-up shows how to position the screwdriver. | | Large Image | Extra-Large Image |
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Figure 18 | | The airbox is now free to be removed. Simply lift it straight up and maneuver it around any hoses or wires that are in the way. | | Large Image | Extra-Large Image |
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Figure 19 | | Here’s a general shot of the right side of the engine bay once the airbox has been removed. Look at all that space! | | Large Image | Extra-Large Image |
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Figure 20 | | The hose leading to the secondary air injection pump can be disconnected to improve access. Here’s the bottom connection, just forward of the turbo. | | Large Image | Extra-Large Image |
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Figure 21 | |
Figure 22 | | Many items in this area are protected from the heat of the turbocharger and exhaust system by heat shields. The coolant line that is connected to the center section of the turbocharger is protected by a reflective sleeve that is secured with snaps. Open the two snaps and remove the sleeve. | | Large Image | Extra-Large Image |
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Figure 23 | | Next you’ll disconnect this coolant line, but first, pinch it shut with a pair of locking pliers that have parallel jaws. There are locking pliers with smooth jaws that are made just for this purpose, but your standard type will do the job too. | | Large Image | Extra-Large Image |
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Figure 24 | |
Figure 25 | | Pull the rubber hose off of the pipe that protrudes from the center section of the turbocharger. A small amount of coolant will escape, but if you clamped the line properly, it won’t be much. | | Large Image | Extra-Large Image |
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Figure 26 | | Above the exhaust manifold you’ll find a heat shield that protects the oil line that feeds the center section of the turbocharger. Remove this heat shield by first removing the 8mm bolts that secure it (31 in-lb). | | Large Image | Extra-Large Image |
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Figure 27 | |
Figure 28 | |
Figure 29 | | Next you need to disconnect the oil feed line at the turbo center section. A 17mm open-end wrench will make quick work of the end of this line (17 ft-lb). | | Large Image | Extra-Large Image |
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Figure 30 | | The line is off and out of the way. You’ll get a little oil leakage out of this fitting, but it shouldn’t be too much. | | Large Image | Extra-Large Image |
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Figure 31 | | Three 17mm nuts hold the turbo outlet flange to the catalytic converter (22 ft-lb). These are tantalizingly visible, but are difficult to remove because of the way the converter flares outward and because the seams of the outer shell of the converter provide an obstruction. This nut is the easiest to remove; the one to the right is a little more difficult to reach, and the one you can’t see, right on the bottom, you will need a swiveling socket to reach. You simply can’t get a straight shot at the nut with a standard ratchet and socket. You might be able to get a short combination wrench on it, but then you won’t have the leverage you need to break it loose. | | Large Image | Extra-Large Image |
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Figure 32 | | Next, remove the 17mm bolts holding the turbocharger to the exhaust manifold (26 ft-lb). These will need to be replaced when you reinstall the turbo. These bolts can be a bit stubborn after hundreds or thousands of heat cycles. You can get a nice deep socket and a breaker bar on the two outer bolts. It also helps to use a little penetrant oil on the bolt a day or two before. | | Large Image | Extra-Large Image |
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Figure 33 | | You’ll need a low profile socket for the bolt next to the block. Make sure your socket is positioned properly and apply torque smoothly to be sure you get the bolt loose. | | Large Image | Extra-Large Image |
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Figure 34 | | The turbo is now loose. A couple more connections need to be removed before you can lift it out of the engine bay. As I walk you through those in the following steps, keep in mind that these can be done before the steps shown in pictures 32 and 33. | | Large Image | Extra-Large Image |
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Figure 35 | |
Figure 36 | | In this photo you can see the actuating rod between the wastegate actuating valve (the cylinder to the right of the photo) and the wastegate linkage itself, which is behind the crankcase ventilation tube in the foreground to the left. Just below that, on the body of the turbocharger, is a 19mm banjo bolt that connects a shorter, second coolant line between the engine block and the turbocharger. | | Large Image | Extra-Large Image |
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Figure 37 | | A 19mm socket will take care of that banjo bolt, but the coolant line isn’t free yet. You’ll also need to remove the bolt on the other side of the bracket from that welded nut just behind the wastegate actuating rod. The problem is that this fastener (or alternatively, the fasteners holding the wastegate mounting bracket to the turbocharger) are difficult to find and reach, particularly if this is your first time doing this project. When you reinstall the turbo, leave the fastener connecting the coolant feed line to the wastegate valve a bit loose. Tighten it down to 7 ft-lb only after you have secured the coolant feed line’s banjo bolt (26 ft-lb). | | Large Image | Extra-Large Image |
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Figure 38 | | The solution I went with was to remove the short coolant hose at the engine block. It is held in place with a 7mm hose clamp. | | Large Image | Extra-Large Image |
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Figure 39 | | Be prepared to dump a lot of coolant when you remove this hose. It’s not the ideal solution, but it will work in a pinch. | | Large Image | Extra-Large Image |
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Figure 40 | | The last remaining connection keeping the turbo from being removed is the hose that provides the vacuum signal to the wastegate actuator valve. This is the hose that runs across the timing belt cover to the intake manifold. | | Large Image | Extra-Large Image |
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Figure 42 | |
Figure 43 | |
Figure 44 | | Here’s the turbine side of the turbocharger, with the wastegate flapper on the left and the turbine wheel on the right. | | Large Image | Extra-Large Image |
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Figure 45 | | This is a closer look at the nut that is welded to the wastegate actuator valve mounting bracket. Because this nut is welded, you needn’t hold it in place as you remove the bolt from the other side. | | Large Image | Extra-Large Image |
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Figure 46 | | Remove the 10mm bolt in order to remove the short coolant pipe from the turbocharger. Again, you can do this while the turbo is still in the car rather than on the bench. See the Turbo Rebuild project next if you’re planning to rebuild your existing turbo. | | Large Image | Extra-Large Image |
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Figure 47 | | With the turbo and airbox removed, along with the hoses that lead into and out of the turbo, the exhaust side of the engine looks awfully empty. Note that I removed the crankcase ventilation hose—it was thoroughly baked onto the metal pipe and had to be cut to be removed. Even then, a good bit of rubber was stuck to the pipe. | | Large Image | Extra-Large Image |
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