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Hi everyone; I have a 2016 GL450 with 215k miles that I've owned since almost new. It's been great for the most part, but yesterday during a normal day of errands and everything working fine, the starter decided to quit on me. When I press the ignition, the starter whirrs loudly for a few seconds and stops, but does not crank the engine. Seems like a bad solenoid; I tried tapping it with a hammer to no avail. I'm going to try to replace the starter, but can't find any videos or steps for the X166 model with the 276 engine. I find lots of info for the 164's, but almost no info for this car. Does anyone have the steps to replace it? Is it done from the top or bottom, does one need to remove parts of the exhaust, or jack the engine for clearance? All advise is greatly appreciated. Cheer all,
For anyone who comes along this post looking for similar instructions, I was able to replace this starter today. This job is much harder than on the x164, for which there are several videos on youtube. I found no information for how to replace the starter on the x166 with the M276 V6 engine.
On a different forum, a user provided the outline of the WIS and it was for the most part spot on. This is definitely a medium to high difficulty job, and I don't recommended it for unexperienced diy-ers. Here are the necessary steps:
REPLACING THE STARTER MOTOR ON THE 2013-2016 GL450 (X166 WITH M276 ENGINE)
0) DISCONNECT THE BATTERY'S POSITIVE TERMINAL FROM UNDER THE PASSENGER SEAT
1) Remove top engine covers, and remove passenger side air filter box with its pipe.
2) Jack up the car and remove 2 plastic covers, the one by engine and the one by the transmission. (8mm socket)
3) Remove the charge pipe that goes from the turbo to the intercooler on the passenger side.
4) From the top of the engine, remove the tiny heat shield covering the clamp for the passenger side catalytic converter (1 E10 Torx screw).
5) Remove the heat shield that covers the passenger side engine mount (3 E10 Torx screws).
6) Disconnect both O2 sensors from the harness on the top of the engine, remove the top clamp of the cat (13mm socket).
7) From the bottom of the car, remove the back clamp of the cat, the nut that holds the cat pipe to the transmission brace, and the bracket that holds the cat to the transmission. The screw on the clamp and the screws holding the pipe to the bracket were VERY rusted on my car. I bathed them on PB Blast for about 45 mins and even though they were tough to remove with a 16in breaker bar, they all came out in one piece.
8) Slide the cat back as far as it will go, turning it and wiggling it to back it up to the point where the body of the cat hits the transmission brace. Be careful not to damage the wires of the cat sensors.
9) Now you have all the clearance you need to reach the starter from both top and bottom. Remove the heat shield from the starter (3 Torx E10 screws)
10) Remove the wires from the starter, solenoid wire is held by a 10mm nut, and the voltage wire is held by a 12mm nut. I removed both blindly from the top of the car with a small 1/4 ratchet and sockets with no extension.
11) Remove the 2 Torx long screws that hold the starter to the engine from the bottom of the car. I used a regular 3/8 ratchet with an extension (I think they are E14 Torx); no swivel necessary.
12) Install the new starter and work backwards to resintall everything.
All this took me about 7 hours. About 5 to remove everything and then 2 to reinstall. I think more experienced guys might be able to do it in 4. The scariest part was messing with the cat because I had never removed it before and was nervous about breaking the rusted screws. This was the most difficult job I've done on this car, but I feel pretty proud about being able to do it. Indies wanted to charge about $3k for this job, and the dealer quoted $8k claiming that the engine had to come out. I bought the starter from AutohausAZ, it was SEG Automotive model 2769064300. Cost total about $270 including the fast shipping. Literally arrived in 1.5 days.
I'll post some pictures I took of how it look when everything is removed (including the starter). If any of the explanations are not clear please ask and I'll try my best to clarify. Good luck all!
For anyone who comes along this post looking for similar instructions, I was able to replace this starter today. This job is much harder than on the x164, for which there are several videos on youtube. I found no information for how to replace the starter on the x166 with the M276 V6 engine.
On a different forum, a user provided the outline of the WIS and it was for the most part spot on. This is definitely a medium to high difficulty job, and I don't recommended it for unexperienced diy-ers. Here are the necessary steps:
REPLACING THE STARTER MOTOR ON THE 2013-2016 GL450 (X166 WITH M276 ENGINE)
0) DISCONNECT THE BATTERY'S POSITIVE TERMINAL FROM UNDER THE PASSENGER SEAT
1) Remove top engine covers, and remove passenger side air filter box with its pipe.
2) Jack up the car and remove 2 plastic covers, the one by engine and the one by the transmission. (8mm socket)
3) Remove the charge pipe that goes from the turbo to the intercooler on the passenger side.
4) From the top of the engine, remove the tiny heat shield covering the clamp for the passenger side catalytic converter (1 E10 Torx screw).
5) Remove the heat shield that covers the passenger side engine mount (3 E10 Torx screws).
6) Disconnect both O2 sensors from the harness on the top of the engine, remove the top clamp of the cat (13mm socket).
7) From the bottom of the car, remove the back clamp of the cat, the nut that holds the cat pipe to the transmission brace, and the bracket that holds the cat to the transmission. The screw on the clamp and the screws holding the pipe to the bracket were VERY rusted on my car. I bathed them on PB Blast for about 45 mins and even though they were tough to remove with a 16in breaker bar, they all came out in one piece.
8) Slide the cat back as far as it will go, turning it and wiggling it to back it up to the point where the body of the cat hits the transmission brace. Be careful not to damage the wires of the cat sensors.
9) Now you have all the clearance you need to reach the starter from both top and bottom. Remove the heat shield from the starter (3 Torx E10 screws)
10) Remove the wires from the starter, solenoid wire is held by a 10mm nut, and the voltage wire is held by a 12mm nut. I removed both blindly from the top of the car with a small 1/4 ratchet and sockets with no extension.
11) Remove the 2 Torx long screws that hold the starter to the engine from the bottom of the car. I used a regular 3/8 ratchet with an extension (I think they are E14 Torx); no swivel necessary.
12) Install the new starter and work backwards to resintall everything.
All this took me about 7 hours. About 5 to remove everything and then 2 to reinstall. I think more experienced guys might be able to do it in 4. The scariest part was messing with the cat because I had never removed it before and was nervous about breaking the rusted screws. This was the most difficult job I've done on this car, but I feel pretty proud about being able to do it. Indies wanted to charge about $3k for this job, and the dealer quoted $8k claiming that the engine had to come out. I bought the starter from AutohausAZ, it was SEG Automotive model 2769064300. Cost total about $270 including the fast shipping. Literally arrived in 1.5 days.
I'll post some pictures I took of how it look when everything is removed (including the starter). If any of the explanations are not clear please ask and I'll try my best to clarify. Good luck all!
Great job, and thanks for sharing! For us DIY guys, it’s jobs like this that help us get better and build confidence.
Over the years, I have always had a tougher time finding DIY support (videos, torque specs, etc) for my x166 compared to my e90 BMW. Last year I purchased a 3-year AllData subscription for our GL and it has been a huge help.
Here's the procedure from WIS, I'm in the process currently. Having trouble reaching the shields so may need a stool lol
that really sucked.
In total, 7.5 hours with a break in between. The blind shield screws are such a time waster, I unfortunately wasn’t able to reach from the top like OP so everything was below. Thankfully all my exhaust bolts were super easy getting off, I did break the locking tab on one of the O2 sensors but it connected back in and doesn’t move.
Putting the cat back on was a two man job and even then was painful, need to hit arm day at the gym after that lol.
It took me a few tries to get the main starter connector onto the new starter, lots of wiggling to get it to go on but I think the eBay brand I bought may share some fault there. I’ll try to pull some camera footage to make a hopefully entertaining timelapse of my driveway job later.
I’ll rate this job a 7.5/10 on the frustration/scratches/pain factor. The little plastic coolant coupler pipe between the engine block and thermostat still takes the cake, $15 part turned into a few hundred due to plastic parts breaking as I removed them and a turbo coolant line fitting breaking requiring a bootleg flush.
Last edited by Bumbleboy92; Feb 6, 2026 at 03:43 AM.
Today while at a red light, the new starter failed in the exact same way. Had to turn off the car and turn back on. Thankfully it wasn’t as bad as before where multiple attempts were needed, only needed one attempt. Not what I was hoping to find after replacing the starter.
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