Potrice

I started the ML yesterday morning and got the red battery icon on my dashboard! The ML turned off all of the accessories to preserve the battery charge. I was heading to my father’s place for a family reunion and after 10 minutes of driving, I noticed a very strange noise coming from the front of the car, along with a strong burning/chemical smell. Once at my father’s place, I checked the voltage going to the battery and it was around 12v. I think the alternator should be delivering around 14v when the car is idling.

So I proceeded to put the ML on the lift and I removed the alternator (a hell of a job) and sure enough, the pulley on the alternator was very tight and seemed seized. The wiring inside of the alternator looks fried/melted.

I usually order my parts on Rockauto and I almost fell down my chair once I saw the pricing on a new alternator! Almost 1200$! I wonder if I can rebuild mine? Do you guys know if there’s a place to get one for cheaper? I understand the alternator is a 220 amp, but the price seems insane.

VIN = 4JGDA2EB4DA231578

The suv has 172 000 km.

peter2772000

You're really not doing too well with this truck, huh?

https://www.ebay.ca/sch/i.html?_odkw...nator&_sacat=0

Potrice

To be fair, I haven't invested a lot of money into the truck since I owned it. Here are the problems that I've had with it (not including maintenance such as brakes, oil changes, etc.):

Bought the suv with around 50 000 km.

- 51 000 km = NOX sensor and blind spot sensors changed under warranty.
- 51 000 km to 172 000 km = no problems
- Now sitting at 172 000 km = 1 rear shock was leaking (changed both), rear wiper motor stopped working and was changed, changed the front passenger side wheel bearing, P20B9 code (DEF feed line heater) and now a dead alternator.

I have invested about 2000$ in parts (in about 4 years and 120 000 km) and I do all of the labour myself. Not too bad in my opinion. Far from being the worst reliable car I've owned (a 2008 dodge avenger!).

Regarding your link, it seems Ebay is very weird when it comes to alternators. The ones listed in your link are for the gas version (3.5L) instead of the 3.0L diesel. It seems that the diesel alternator is much more expensive? Hmmm....

peter2772000

In actuality, you're not doing too bad then.

Not all are 3.5 litre versions. Look again...

kombifan

The part is expensive. I'm seeing mb branded reman units going for 1000

The rockauto one was 800

Weird.

https://www.mbwholesalepartsonline.c...r-000906352280

Potrice

So I replaced the alternator. The old one was almost seized (I think the bearing was shot) and the wiring was all burnt inside. It was non repairable. I received the new alternator and installed everything. I also ordered and installed a new serpentine belt https://www.rockauto.com/en/moreinfo...sn=424&jsn=424

I put everything back on and the serpentine belt seems a little too long (not as tight as the original one). Anyways, I start the truck and check the voltage near the passenger side cover where the positive and the negative are. I'm still getting 12v coming from the alternator, so the battery isn't charging! What the %^&*. This is with a brand new alternator. Also, while idling, the truck made some squeaking noises. I think the belt is too loose. I'll put the original one back on for now. I'm really baffled and stuck here. Any suggestions?

Potrice

Well it turns out the new belt doesn't fit. Maybe Rockauto sent me the wrong one. I'll simply return it. I installed the original belt back in and voila! Getting 14v and everything is running fine! Yay!

peter2772000

Awesome, glad you got it figured out.

Curious; You telling us that the alternator wasn't giving full voltage simply because the new belt was loose?

Potrice

That is correct. I don't see any other explanation because I installed both belts correctly.

peter2772000

Never woulda guessed it. I can understand how an under-tensioned belt would cause slipping at high load and or rpm. But just at idle?
Unless your battery was so discharged that it was throwing a huge load. Either way, good to know, thx for sharing.