Herbertm

Sounds like rattling noise. At first suspected dash fan but persists when fan is switched off. Started about a month ago. Today the noise persisted when engine turned off. I raised the hood and it seems like it might be coming from the large silver round box mounted near the driver. Anyone have any ideas or similar experience?

Herbertm

Posted last night about noise in engine compartment. This morning the noise continued. Motor off, key out so I assume was making this noise all night. Sounds like rattling and static.

Any ideas?

tusabes

Uh oh. Sounds like your airmatic pump was running when it shouldn't be . This is due to a defective relay. Your pump is likely burned out now.

If the car is not slammed to the ground already drive it straight to the mechanic because it will soon drop so low it cannot be safely driven or even towed or flatbedddd without damage

tusabes

If the pump is still making noise , its not burnt out yet- immediately pull the relay or disconnect the battery until you get a new relay.


See the sticky start here thread this I's a common problm I keep a relay in the car in case mine ever goes out

redcoupe

So is the noise on the driver side or the passenger side? Because the airmatic pump is on the passenger side under the headlight.

Herbertm

So here's the thing. The noise sounds like static and rattling. Weds. evening I turned the dash fan off and the noise went away. Thursday evening I turned the fan off and the noise persisted, even after I turned off the motor!

The noise persisted all day Friday with the motor off. Sounded like a loud-ish static, like a radio which can not tune into a station, sort of. Friday evening I moved the car and the noise stopped! Came on when I turned the dash fan on and then went away when I turned the fan off.

Today, Sat. the noise only persists with the dash fan on. The noise does not get louder with increased fan or if I rev the motor.

The noise is seems to come from the area in on the drivers side and kind of where the brake vacuum box is.

I showed it to a certified MB mechanic on Weds and this morning and he told me not it's the fan and not to worry about it. I sure would like to diagnose the issue but do not want to spend a lot of money doing so.

I am concerned if it's related to the air shocks. Esp. if once they go I can not tow the car. The what?

redcoupe

With out being there and hearing the noise I couldnt really say what it is but it def doesn't sound like the airmatic pump

Herbertm

Thanks, I appreciate your response and input. For now, I'm going to wait and see if something else develops.

tusabes

Well if the noise is going on and off with the fan then it doesn't sound like it's the airmatic pump

Has your car been out in the rain or car wash recently?? Something may have shorted out from getting wet

Herbertm

Thanks for your response. Now it is definitely linked to the fan. When the fan is on there is rattling noise which goes away when the fan is off. For now, I think that I'll live with it. Doesn't seem worth it to remove the dash to address this.

DAMIT

If you are sure that is the Heater Fan (Although how it was still running when switched off is a mystery!) It is a common problem. The result of a blocked drain in the air intake, which allows rain water to fall on the motor fan causing corrosion on the main fan bearing over time.

Relatively easy to get to from under the footwell, but as expected expensive to replace!

Can be purchased new on fleabay most days saving a third on stealership prices.

Herbertm

Thanks, I'll look into it.