Water gurgling sound in dash
 

Hi All,

I remember some past discussion about strange water gurgling sounds in or under the dash. I now have this in my 500E especially when going up hills or at start-up. What could it be? My car has about 110K miles. Sometimes it will fog the inside windows with moisture on start up as well, especially when its hot outside, but I don't know if these two symptoms are related or not. A data base search did not bring up anything other than air in the heater core.

Thanks for any advice,
Eric

Very probably you have a leak in the heater core or control valve.

I normall do not believe in any anti-leak stuff. But when I had that problem in my already sold 300E, I added a small bottle of these raditor leak fix and it worked. It still had no leak when I sold the car after some 25k miles.

Bo

I believe that's a symptom of air in your a/c system also. Check the sight glass on the receiver/dryer for bubbles.

Is the condensate from the A/C dribbling on the ground as it should? If not find the tube where it should be coming out and see if you can probe it without causing any damage to the outlet tube (it's probably a soft flexible rubber).

Ernie

Anti-percolation kit
 

I had this problem in a car I have since sold - a 1989 300E. Mercedes dealers will install an anti-percolation kit to solve it. I don't know what the kit consists of, but this might put you on the right track.

The gurgling noise is probably air in the coolant. Mine does that after coolant has been changed. The best way to handle that that I've found is to fill the coolant tank nearly to the top. After a few heat up/cool down cycles this will generally purge the air.

RE: fogging windows, this is a common problem with aging climate controls. Mine also does that, since it sends air to the defroster vents when first started before the vacuum servos have a chance to route the air to the AC vents.

Ok, my car does the exact same thing and the last post (about air in the coolant) makes a lot of sense. My car ONLY does this at startup (though, not on a "hot" startup / restart).

* My a/c condensation DOES drip out correctly.

So, do I just top it off and let it run, do I do this with the cap or or off?

Also, weird situation here, my car's a/c works great -- all the time. HOWEVER, when I go up a very long, extended hill -- like 5 miles up a mountain -- the a/c stops blowing cold and then fogs up the windows.

What is this, and are these things related (gurgling in dash)?

gurgling in dash
 

When I drained my cooling system and replaced my rad and auxilliary water pump, the car did it once or twice, when moving off from standstill. I topped up my cooling system, and after another drive or two, it hasn't done it since. My guess is that some of the hoses are at a level almost equal to the water level in the coolant reservoir, if the coolant level is low, water passagges located high in the car will still have air in them.

Good luck.

John