Hot Battery

[Alan S]

Today I decided to take the merc on its first road trip, to Iowa, a 4.5 hour drive. Approx. 2hrs into the trip, we noticed a funny smell, pulled over, and opened the hood. I noticed the smell came from the battery which was hot and was hissing. I also noticed it was leaking some fluid. I took it to a local shop where I purchased a new battery. I thought maybe the old battery was going bad. Well, 2 hrs later, we made it to our destination, but after getting out of the car, I noticed the smell again. Opened the hood and the new battery was hot, but not leaking. I've owned the car for several months now, and the car always started in the cold Minnesota winter. The only electrical problem I have is my climate control fan sometimes works and sometimes doesn't. I also noticed in the past that when the climate control fan used to go to high, my lights would brighten. Am I in for a lot of expense? Could my alternator be overcharging? Please help, thanks

The condition you describe should never happen. It sounds like a bad alternator. If it's the usual MB prices thats probably three hundred plus. You might check the battery voltage with the engine at a fast idle, it should be about 13.5 volts.
If it's much higher, I'd be real careful about turning on the radio etc. The last thing you want to do is fry all that expensive Bosch electronics.
The well informed tech experts that frequent here can give a better diagnosis, but that's my two cents worth.

[Hazen]

Zounds as if der voltage regulator is gersprotzgen! Voltage regulators are relatively imexpensive vis a vis der alternator, and easy to fix, too!
Good luck,

[Benzmac]

I have seen this, in both cases, it took a new alternator to repair. You could get a price in the fastlane at the top of the screen.

Also, be sure to check this soon! You could damage windows, lights and computers in the car.

[Alan S]

Thanks everyone, it was the alternator. It was putting out 22 volts!