bru023, recommend checking the power steering fluid level and replacing the accessory drive belt when you replace the tensioner mechanism. Hopefully, the engine in your 1994 E320 has the newer style belt tensioner ... without the tensioner rod and shock absorber. That style is much simpler to replace, and no adjustment is necessary ... a far superior design to the tensioner in the older 124 cars. Also, check if the alternator is a Bosch with a voltage regulator attached to the back with 2 screws. If so, the voltage regulator brushes may be worn down so much that the alternator doesn't recharge the battery sufficiently.

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Fred Hoelzle