Buzzing on startup
 

Hi all,

Lately I have noticed that there is a moderately loud buzzing sound coming from the front passenger side of the engine compartment at startup. The buzzing continues for about a minute and then stops completely. It does this every time and stops buzzing at the exact same time interval after starting.

Is there an obvious cause (ie: common problem on these cars) that you would immediately be suspicious of? I'm just trying to get some ideas before I actually start poking around under the hood this weekend.

Thanks!

Mine has done this religiously upon startup since I purchased the car 6 years ago. Never gotten worse either.

I never got a consistent answer from anyone on the source of the buzzing...so I lived with it and chalked it up to a "personality" trait of the W124...

Me too. I've been told oil pump as well. Same as tkamiya, g-benz, mine has done it since I've had it. It can be louder or quieter depending on the weight of oil I'm using and the outside temperature. I've found that more viscous oil (15W-40, for example) tends to be a bit quieter, but it's still there. Hasn't changed since I got it, and the stealership says either cough up $600 or so for 1 more minute of quiet, or leave it alone because it's just a noise and it's not gonna break.

I have a 98 C230 that has the same buzzing. Sounds like its coming from inside the passenger side kick panel. Lasts about 3 or 4 seconds.

Is it possible that there is an aspirator blower, the fan that pulls cabin air through a tube and thus over the cabin temp sensor?

My 86 300SDL (W126) has such a blower, under the glove compartment, and sometimes makes noise on startup.

BTW, it makes noise before the engine actually starts. If yours only buzz after engine start, then, nevermind... :D

Best Regards,
Jim