Frankiestanley

Does anyone have any idea what would cause a really loud engine noise to start when I go over 45 MPH and the temperature is around 70 degrees or below?
It does not happen during the hot summer months only when the temperature drops and I go over 45MPH?
Thank you

DUTCH

"really loud engine noise" needs a better description.

Frankiestanley

Thanks for replying.

It's a constant loud humming sound, like some described once like a large swarm of bees.

calemonlaw

If it's hot outside like it is today, the fan runs on my 2002 G500...but it doesn't go on-and-off. It shouldn't run at highway speeds, only when there isn't enough airflow over the radiator. You should get it checked by the dealer if it happens all the time. You could hit the little wrench button in the arm rest and see what the MB technicians say. I've done that from time to time and they are very helpful.

Frankiestanley

Hey thank you very much I will give it a try.

Mike

grane

Does it make the same noise when you are parked and rev the engine to the same rpms?

Drive the car until you have the sound then find a safe place to pull over or return to your driveway and perform the test above. An assistant would help pinpoint the noise.

Good advice from the OP above but there could other possibilities, I reckon.

Frankiestanley

I will try anything before heading to the dealer.
Thanks,

Mike

calemonlaw

I noticed last year on the Moab trip that the G500s had loud fans. They ran a fair amount even though the ambient temps were pretty low. That is slow going though and the engine has obvious cooling needs. the fan in my '90 300GE was really loud too.

Frankiestanley

Thanks for responding. I really need to bring it to the dealer and take a look. The voice can come and go and usually improves as the temperature gets warmed and the more I drive it during the day.

Thank you