My 2003 Mercedes C240 makes a clicking sound like it's percolating not only when it's hot, but in the morning when it's cold and has set-out all night. Sound's like it's coming from the underneath the passenger seat just above the plastic shield that covers the bottom of the engine. What is it? No problem messages on dash. No performance problems. Please help.

 

My 2002 C240 2.6 V6 Auto has water leaking into gearbox from integral oil cooler in radiator causing erratic engaging of gears 1 & 2. Can anyone please advise if this was a "recall" matter.