So, early this morning at 430 am, me, the wife and one of my kids left MIllbrae to go to Folsom CA in our GL63. It was supposed to be a 2 hour drive. Well, when we got to Vallejo, the red battery symbol was displayed on the dash. I immediately knew what the issue was so I told my wife that we needed to go back home. We were about 45 miles from home. On the way home, the car started to shut down various systems. The very first thing to shut down and it happened that same time as the red battery coming on was the command system. As we continued to drive back at about 80mph, blind spot assist, then active curve system, etc was being displayed as inoperative on the dash. One by one, the car was slowly shutting down. Luckily, it was fairly empty on the freeway. We finally got to the bay bridge and the dash lights and headlights shut off except I could see the running lights remained on. If I gave it more gas, it started to bog and lose power so I maintained a steady pedal. We got to the peninsula and right when we hit the 380 junction, the car lost power though it continued to run. I pulled over to the shoulder only 3 miles from home. The funny thing is that I could not get the car to shut down. It felt like it was dieseling for a few minutes. I even put the key into the ignition to try and manually turn it off but it continued to run. The flatbed came in about 30 minutes to take us back the last 3 miles. He hooked up his jumper wires to our car and I was able to drive it on and off the flatbed as if nothing had happened.

The battery is about 4 years old but I was able to drive back about 40 miles on the battery alone.

Anyway, I just wanted to share my experience that I had today and I already got the alternator out to be replaced. I decided not to just replace the voltage regulator since my AMG is already at 200k miles.

 

When did the first one go out on your 63?

 

What did you have to remove/disconnect in order to get the alternator out? I'm at 190K+ miles and debating between replacing just the voltage regulator or the whole alternator.

 

Blown, the red battery light came on about 1/2 mile away from the next exit yesterday morning.(sat 04/27/24.) The command then shut off almost simultaneously and I immediately knew what happened. Being 45 miles away from home at 5:15am, I knew I didn't have much time so I boogied back home at a decent pace.

Edit, Blown, I just reread your post. do you mean how many miles? At 190,200 miles.

MTM, I was going to do the voltage regulator but there were none around locally. The Benz dealer said the closest one was in TX and that it would take a while. Even Amazon didn't have them close by. There were also no alternators close either but I called Orielly at 8 am that same day and they were able to get one from 100 miles away by 3 PM. I bought it. I'm glad I went that route of replacing the alternator. Aside from just doing the voltage regulator, I would have had to buy the new plastic cover. When I went to grab the alternator rear plastic cover, the entire thing disintegrated into small pieces. The brass bushing from where the brushes contact was also worn pretty and I knew that I would have had to replace pretty soon also.

Removing the alternator was pretty taxing. It took me a few hours whereas assembling everything only took me 2. I didn't unplug the positive from the battery. Instead, I unbolted it at the jumper point under the hood. The one that goes to the starter is not the brass jump point but the one right next to it that is also a 13mm bolt. Once you unbolt that, the positive is disconnected from the alternator. The items that needed to be removed were the air intake tubes to filter, front fan assembly, upper coolant hose at the radiator, overflow hose assembly, serpentine belt, passenger side turbo intake charge pipe, turbo coolant line to the front of the block, and bottom catch tray. Loosen oil cooler hoses. There are only 2 e torx bolts that hold the alternator to the mounting points. Disconnect those 2 wires. It is almost impossible to get to the positive lead on the alternator so once you unbolt it, I found it easier to use a 13mm with extensions and a cordless impact and it unbolted easily. I went from the area by the rear of the lower control are forward. Before doing that, you will need to remove the plastic protective cover that covers the positive bolt and stud with a long pair of pliers.(This is just a friction fit and plastic so be careful to not squeeze too tight. With the AMG hydorlic stability control and all the cooling hoses, I didn't see a way to get it from under the car. There was a way to get it out through the top but you will have to maneuver it through the hoses and then in between the other turbo intercooler air intake. I didn't have to remove this bit it is a very tight squeeze as the alternator might damage the radiator fins so you might want to protect that.

I think that's it for having to remove that alternator. putting everything back was pretty quick and really no issues. Though this new alternator was rebuilt, it is a Valeo alternator as per the markings on the case. I was able to get my standard military discount from Orielly so that helped out pretty well.

 

Thank you for all the details! Sounds like a royal pain.

 

Hey MTM, Btw, the above was for a gl63. Your vehicle may be a little different if it's a gl450 as I'm sure there aren't as many obstructions so it may be a bit easier to remove. I edited my original post.

 

Yes, you are right, I replaced mine today. All I had to do is disconnect two oil line brackets to move them aside and that cleared enough space for alternator to be removed.

 

In talking with my mechanic the magic number for the alternators is around 200k miles. His x163 went out at like 203k. He has had 3-4 customers go out between 190-220k. I’m no borrowed time at 240k but I’ll get it before 250k if it makes it that far. I stay on the interstate almost exclusively and that seems to be easier on everything so I’m going to try and make it. Dang alternators are expensive!!

 

Just as another data point - I replaced mine at 192K miles, mostly highway. The regulator brushes were at 2-3mm, so almost gone. You can see the pictures here: https://mbworld.org/forums/gl-class-...h-mileage.html