Teutonic_Driver

I posted last year about the SRS light that went off in my 2000 E320 4matic sedan. About how my Youcanic scanner reset the dash light, but how it kept coming back. About how I took out the passenger from seat and examined the seat pad sensor and its connections. About how the error attributed the SRS light to a voltage issue in the passenger side door's airbag squib. About how I took it to the MB dealer here and they reset the light and it stayed off.

Well, it stayed off until about two months ago, and then came back on. I was procrastinating taking it back to the MB dealer to fix -- expecting it to be a $2,000 job to replace the seat sensor, do diagnostics and gosh-knows what else. I mentally prepared myself to just pay it because it was cheaper than buying a new car and my car is in such great shape.

Well, a strange thing happened with (maybe) a happy ending??

My son, who's the main driver, calls me from the car and says he thinks he smells burning oil. I knew my valve cover breather covers were leaking (as they all do), so I told him not to worry. I bought the fix-it kit from MercedesSource.com and was planning on dedicating a day to meticulously cleaning and reinstalling them.

That night, my other son accidentally left the parking lamps on. I discovered it the next morning, but the battery (a new AGM) seemed fine. Later that day, my son calls me and says the dash warning said: "Battery / Alernator, visit workshop." I figured it was because the battery was run down and the alt was busy working hard to charge it back up.

That night, I decided to idle the car in the driveway to make sure the battery was fully charged. Smoke started pouring out from beneath the hood. HUGE amounts of it. Like "your valve covers came off and motor oil is pouring onto a hot exhaust manifold" levels of smoke.

I shut the engine off, popped the hood and discovered that the smoke was coming from the OEM alternator.

I removed it. The shaft spun with a crusty feeling (shot bearings?) and it stunk like burnt plastic. I could see melted debris inside the aluminum rib cage.

I replaced it with a new one from auto zone, and then reset all the warning lamps using my Youcanic scanner.

You know what? The SRS light turned off and stayed off. Every time I tried to clear the SRS light before it would return. Not this time.

Here's the helpful part of this story:

1. the alternator was probably dying last year and throwing eratic voltage levels which caused the voltage issue with the passenger side airbag squib.
2. the car only has 84,000 miles, so age of components can be as important a factor in lifespan as mileage.
3. the alternator I first got from auto zone was incorrect. Even though I gave them the proper Make/Model/Year. We even tried VIN. It kept returning the wrong alternator part. So I asked them to look up the alternator for a 2001 version of my sedan. *That* returned the correct alternator.

I hope this story can help others who will face similar issues in the future. I know I've benefitted from this community's knowledge. Just paying it forward!