I have a 95 e420. runs great with no problems. however, it has a throaty sort of rattle sound when idle? Someone told me that a secondary water pump sounds dry? Secondary? is this anything to worry about? The sound is sort of like a marble rolling across a wood desk..only constant as long as the engine is running..as it revs up..it quietens down.

 

noise from exhaust?

 

this noise is right up front....sounds seem to be coming from front drivers side ...fairly close to the radiator. it does not sound like a bad water pump from my chevy experience. sounds like a really noisy pully but has an enclosed muffled sound....best i can describe it is a marble rolling across a desk. i have sort of heard a similar sound from FWD vehicles that have the exhaust manifold on the front of the engine...but they tend to be consistent with the sound. this sound after 15-20 minutes of running..pretty much goes away.

is there a such thing as a secondary water pump?