2004 c240 with 80k miles. Today I hear a loud clicking noise from the engine, driver side near belt pulley tensioner. The noise sounds like a diesel engine. Clicking gets faster with engine speed. At certain speeds the noise stops. Air conditioner also blows warm air only. No error codes. Tensioner pulley probably needs to be replaced because it was squeaking a bit a few days ago.
Any ideas? AC was working fine yesterday. Noise and AC problem started the same day.