Dead turbo in 2008 ML320
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2008 ML320 CDI
Dead turbo in 2008 ML320
Lost boost the other day on the highway. Got it to a local shop last week. They found that the compressor impeller was literally broken in two.
A new OE turbo is out of budget for sure. The car has about 220000 miles on it.
Trying to decide whether to rebuild it, or replace it with aftermarket. There are aftermarket cartridges for anywhere from $84 to $400, and aftermarket complete new turbos for $350 to $900. A new OEM looks like $1500 or so.
One guy has both cartridges and whole units, and says his unit is a drop-in replacement for the original, but that I have to replace the brace. He has not been able to explain why.
So, any advice on rebuild vs replace? Looks to be a fairly easy job to rebuild, but I haven't opened it yet, so I don't know whether the nozzle vanes were damaged by the input impeller.
A new OE turbo is out of budget for sure. The car has about 220000 miles on it.
Trying to decide whether to rebuild it, or replace it with aftermarket. There are aftermarket cartridges for anywhere from $84 to $400, and aftermarket complete new turbos for $350 to $900. A new OEM looks like $1500 or so.
One guy has both cartridges and whole units, and says his unit is a drop-in replacement for the original, but that I have to replace the brace. He has not been able to explain why.
So, any advice on rebuild vs replace? Looks to be a fairly easy job to rebuild, but I haven't opened it yet, so I don't know whether the nozzle vanes were damaged by the input impeller.
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2008 ML320 CDI
I decided to try to rebuild it. I ordered a replacement cartridge that was listed as being specific to my model year and OE part number. Also ordered the hardware kit from FCP Euro.
Once I get it out of the car and opened up I will know more. Worse case, I think, would be that the input impeller damaged the nozzle vanes.... but there may be a worse worst case if the front impeller damaged the front part of the housing.
Once I get it out of the car and opened up I will know more. Worse case, I think, would be that the input impeller damaged the nozzle vanes.... but there may be a worse worst case if the front impeller damaged the front part of the housing.
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2008 ML320 CDI
I am totally stuck on removing these rear E12 bolts. Heat didn't help. PB Blaster didn't help. It's not easy to get much torque to them, but I've got a couple of flexible tools, and even welded together a right angle offset tool, and I've gotten enough torque to them to start bending the E12 ridges.
I'm thinking that if I can remove the wiper deck, I can get in there with an angle grinder to at least cut off the PS one. The DS one is too close to a sensor for angle grinder in there, but I could at least apply more torque to that one, then.
It's really annoying that they didn't put the turbo in in a way that exposed all six of the bolts that hold the core to the exhaust section. Those bolts loosen easily, and it's only the core I need to replace. Five of the bolts are reachable. The sixth is right underneath the turbo...
I'm thinking that if I can remove the wiper deck, I can get in there with an angle grinder to at least cut off the PS one. The DS one is too close to a sensor for angle grinder in there, but I could at least apply more torque to that one, then.
It's really annoying that they didn't put the turbo in in a way that exposed all six of the bolts that hold the core to the exhaust section. Those bolts loosen easily, and it's only the core I need to replace. Five of the bolts are reachable. The sixth is right underneath the turbo...
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2008 ML320 CDI
Well, my best guess is that removing the wiper deck would also require removing the windshield. Not an appetizing option.
I did manage to remove the front part of the turbo, as the cast iron lip of the middle section was actually broken in one area... The front has a bit of scarring inside, but I think it will be OK. I'll need new washers for the 8mm bolts.
For the rear bolts. I don't think it will be possible to unscrew them. I think I'm going to need to spend a lot of time with a Dremel, flex handpiece, and many cutoff disks, to cut the bolt heads off.
I did manage to remove the front part of the turbo, as the cast iron lip of the middle section was actually broken in one area... The front has a bit of scarring inside, but I think it will be OK. I'll need new washers for the 8mm bolts.
For the rear bolts. I don't think it will be possible to unscrew them. I think I'm going to need to spend a lot of time with a Dremel, flex handpiece, and many cutoff disks, to cut the bolt heads off.
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2008 ML320 CDI
I was able to cut off one bolt head (top passenger side) with a die grinder. Not sure I can cut off the driver side top one... doesn't look like there's enough room to get in there with a cutter. The bottom one also doesn't want to loosen, and I can't even see that one, so no idea what to do there... unless I cut off the whole outlet. That seems ridiculous. What do shops do to get these bolts out?
Last edited by SQLGuy; Aug 26, 2023 at 09:53 PM.
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2008 ML320 CDI
And the saga still continues. I bought a super compact 700 lbft air impact wrench. There is just enough room to get this on the bolt. But it still doesn't move. I might try some heat again...haven't tried that yet for this bolt.
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2008 ML320 CDI
Spent several hours on it today. Result is that I've ground away most of the head and flange of the drivers side bolt, and I got the passenger side bolt out. For the PS bolt, when I had ground the flange down to almost nothing, I noticed that it was moving, and it threaded out with just finger pressure on the sliver of the flange that was left. So, that bolt, at least, wasn't rusted or otherwise frozen to the casting it was threaded into... it was just extremely overtorqued.
I'll need to attack the DS one again tomorrow with some larger diameter grinding wheels, as I can't reach anymore with a 4" wheel. I even tried a file, but there's no room there for a file either. With a rigged up 4.5" wheel on my die grinder, I should be able to remove the rest of the bolt flange.
I hope the manifold bolts are easier once I can get to them...
I'll need to attack the DS one again tomorrow with some larger diameter grinding wheels, as I can't reach anymore with a 4" wheel. I even tried a file, but there's no room there for a file either. With a rigged up 4.5" wheel on my die grinder, I should be able to remove the rest of the bolt flange.
I hope the manifold bolts are easier once I can get to them...
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2008 ML320 CDI
Latest update is that I got the head completely ground off the DS bolt, but, unlike the PS bolt, this one didn't want to thread out once the head was down to a sliver. Since the bolt is still there, I can't slide the elbow up and off. I might try removing the bottom bolt, to see if that allows enough movement to pull the elbow off the remaining bolt.
I guess, for a shop, it would make a lot more sense to cut off the elbow, at $170, rather than spending hours fighting with these bolts.
I guess, for a shop, it would make a lot more sense to cut off the elbow, at $170, rather than spending hours fighting with these bolts.
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2008 ML320 CDI
The turbo is out!
Removed the bottom bolt, that only normally needed to be loosened, and the exhaust clamp, and was able to pry the elbow over the stub of the DS bolt. The stub then unscrewed just fine by hand.
The rest of the bracket and manifold bolts came out just fine.
Good news is that the hot side of the turbo looks fine. It's only the cold side that broke apart, so the vanes should be fine.
Removed the bottom bolt, that only normally needed to be loosened, and the exhaust clamp, and was able to pry the elbow over the stub of the DS bolt. The stub then unscrewed just fine by hand.
The rest of the bracket and manifold bolts came out just fine.
Good news is that the hot side of the turbo looks fine. It's only the cold side that broke apart, so the vanes should be fine.
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2008 ML320 CDI
Got the turbo disassembled, swapped out the core, and reassembled. Interestingly, the new bolts are all copper coated. I guess I wasn't the only one who had trouble with the old ones freezing. Hope to finish reinstalling the turbo tomorrow.
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2008 ML320 CDI
Went back to try to remove that broken off bolt that has the ball on top to support the engine cover. MIG welded some steel to the end of the stub (which was sticking up about 1/8") and then welded a nut to that. That allowed me to unscrew about another 1/8" of it from below the level of the aluminum casting before it broke again! Whatever was done wrong here - cross threaded, excessive thread lock, defective bolt, etc... was pretty comprehensively bad. I drilled it out best I could and installed a Helicoil. Hopefully that will do.
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2008 ML320 CDI
Finished the job over the weekend and yesterday.
When rebuilding the turbo, 4 of the 5 stainless M4x.7 10mm Torx bolts that hold the cover for the vanes broke upon removal. This is apparently quite common. Ace hardware had some Allen ones that fit well enough.
Made a replacement for the ball top bolt that holds the air outlet from the turbo - TIG welded the cut off top of the old bolt to a new M6x1 bolt. That came out pretty well.
Had to drill out and Helicoil the one manifold bolt piece that had broken off in the manifold flange. That would have been more of a pain, but, fortunately, I bought some tap drive sockets last year for a different project.
Other than these things, the reinstall went smoothly, and the car runs well now.
When rebuilding the turbo, 4 of the 5 stainless M4x.7 10mm Torx bolts that hold the cover for the vanes broke upon removal. This is apparently quite common. Ace hardware had some Allen ones that fit well enough.
Made a replacement for the ball top bolt that holds the air outlet from the turbo - TIG welded the cut off top of the old bolt to a new M6x1 bolt. That came out pretty well.
Had to drill out and Helicoil the one manifold bolt piece that had broken off in the manifold flange. That would have been more of a pain, but, fortunately, I bought some tap drive sockets last year for a different project.
Other than these things, the reinstall went smoothly, and the car runs well now.
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2008 ML320 CDI
I guess I jinxed that. The car was running great yesterday, maybe even had more power than before... this morning, the turbo is not blowing. No CEL, yet, but there wasn't originally, either. Very disappointed. I guess I'll pull the intake Y this evening and see what I can see about the motion (or not) of the impeller.
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2008 ML320 CDI
Pulled the Y, found that the impeller was indeed stuck. Why? Because the nut at the end of the impeller was loose and almost off. I put some red Loctite and tightened it as well as I could. But I don't have great confidence in that. Going to drop a not very happy note to the seller now...
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2008 ML320 CDI
Well all did not end well here. The replacement cartridge from eBay had a couple of problems. One is that the alignment pin is in the wrong place. Another is that the nut that holds the impeller in place was not tight. That was bad. Worse was that something went wrong with the actuator lever that made it hard to move. The effect is that the car drives fine for a while... 10 to 30 minutes... then loses power. Shut it off and restart it and it will run just fine for another 10 to 30 minutes. Unfortunately, the seller, who promised a replacement cartridge, instead made excuses about not having any in stock until the feedback period expired. I am in the process of moving internationally, so I don't have a place to work or tools to work with. End result is that I'm going to junk the car on Friday. :-(
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ML 63 AMG
Originally Posted by SQLGuy;[url=tel:8883660
8883660[/url]]Well all did not end well here. The replacement cartridge from eBay had a couple of problems. One is that the alignment pin is in the wrong place. Another is that the nut that holds the impeller in place was not tight. That was bad. Worse was that something went wrong with the actuator lever that made it hard to move. The effect is that the car drives fine for a while... 10 to 30 minutes... then loses power. Shut it off and restart it and it will run just fine for another 10 to 30 minutes. Unfortunately, the seller, who promised a replacement cartridge, instead made excuses about not having any in stock until the feedback period expired. I am in the process of moving internationally, so I don't have a place to work or tools to work with. End result is that I'm going to junk the car on Friday. :-(
