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Water, wave, dripping sound

1709 Views 10 Replies 7 Participants Last post by  Jase
I noticed a water dripping noise coming from the dashboard when I turn on the heater. I thought of nothing at first two days then decided to pop the hood yesterday. I saw a unplugged that is conneced to the side of the fan which is connected to the coolant reservoir -- about 3 feet hose. Turns out the it was slowly spraying coolant to the side of the ABS housing. The coolant level wasn't low enough to lite up but I was lucky enough to check and popped the hood.

Whew, good thing it would have been a little more than $6 coolant quick fix up if I didn't check.

She is running like a champ again. I just push the plud in and make sure it's in tack. So far so good! no more leak and water noise in the cabin!
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Hello everyone. the sound you are hearing is due to some AIR trapped in the heater core (the part that gets hot from the water). You NEED to get as much out as possible because the air 'gurgling' around inside causes corrosion of the metal parts, thus a leak is coming, sometime.

See; "Possible Problems" down the page:

Heater core - Wikipedia, the free encyclopedia

My car had a retrofit device added by the dealer to help remove (and prevent) the air from becoming trapped.

A good MB tech (shop) should be able to 'bleed out' the air.
I don't know what the part is called, but I know it was added on because I found it out on that 'official' MB parts site that I signed up for.

I don't know if it was used on other cars than the 300CE.

One method of bleeding the air out is to raise the front end of the car up as high as you can, like 2ft. then with the engine warmed up, run it for 5 minutes at approx. 2000 rpm with the heater on high temp setting.

The air should come out and go to the plastic bottle.
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