rsracing1

My alternator went bad yesterday, thought it was going to be the regulator but once I dismantled the regulator I noticed the diode pack had overheated and melted in areas. See attached picture. I read about others smelling a slight plastic/electrical smell and voltage dropping causing the battery errors on dash to pop up. Based on this it made sense to replace the alternator. After a few hrs or looking through the process I managed to unbolt and remove the alternator with only removing the fan housing and a few hose brackets. Bit tricky getting it out but managed to manipulate the hoses with no real problems. ordered a replacement alternator that arrives tomorrow and will document the install with pics including fan housing etc

On the other hand in leveraging the alternator from its mount I broke the plastic idler pulley. The one that has the double pulley just above the alternator .... was not a happy chappy. Anyone know where to get a good replacement? is there an aftermarket upgrade that is better quality than the OEM? I need to order this asap as we are going on a road trip with the family Friday morning and need to get a replacement fast.

Tried to load my pictures of the burnt alternator but would not load, I'll try to load these again later tonight.

Sir-Boost-a-Lot

iTrader: (1)

I'd use that opportunity to get one of the aluminum idler kits from Shardul. Your stock ones were going to fail soon anyways.

rsracing1

Thanks for the info...Have just ordered the pulley kit from Shardul for next day delivery. Since I have everything removed I decided to replace the supercharger bearing with the nachi replacement bearing from Shardul as well.

Alternator is scheduled for delivery this morning and will try to document with pictures the install on how I get it in with out removing/draining cooling system

Sarc1218

Anyone know what may cause this?? About a month ago I was driving and smelled an electrical fire I pulled over and it was my alternator. I had my sl55 towed home and replaced the alternator with a new one. Well just last week the same thing happened, dash lights, red battery /altermayor loss of brake power etc. I replaced the alternator again and I'm worried it may happen again. The car drives great just want to take preventive measures, can grounding issues cause this or perhaps a low battery overworking the alternator???

Max.H

That blows…. if you make your own thread about this. I bet someone can help you. A lot of experienced folk here willing to helps.

What went out on your alternator? Was it the voltage regular or something internal?

FLE55AMG

Thanks for the DIY write up. I had to tackle this on Saturday myself. I replaced the voltage regulator first but my car under full load (100% WOT) would lose voltage and give me the red battery warning.

It was a major pain and i did end up pulling the radiator hose to clear the alternator out.

One working is be mindful of the radiator support bracket. Under the bracket is the wire to open the hood and those clips need to be removed or you can run the wire off track and then the hood does not open.. Also while you in there get a new belt and tensioner if it's within you budget. I wish I did because now I need to go back in there to replace those items