faz999

Hi guys quick question E350 2009 60K out of warranty but i do have after market extended warranty 7 / 100K

When i turn on the heat i hear a humming / buzzing noise like the fan is on i never notice it before but it nay have been there not sure.

Should i be worried ? when i am driving i do not hear it or when the radio is on only time i hear it when the car comes to stop on a traffic light or when i am i am stopped/

again when i turn of the heater it goes away don't know if it is the fan or the blower or what ?

its not a big deal just curious if it something i need to look into or keep going

Thanks

Plutoe

Do you believe the noise is constant regardless of the fan speed or does the noise increase or decrease with fan speed.

A side bar, when was the last time you replaced or cleaned the cabin filters

faz999

Thanks for the reply it is always constant regardless if the level is on 1 or 7

Cabin filter don't know but it has regular service A and B done at a regular intervals

update: i only get the humming noise like the motor fan is on not to loud just a constant noise. when i turn the AC on it goes away so it only happens when i turn the heat on

currently in Chicago weather is very cold