My E320 has a heart beat! IT'S ALIVE! - PeachParts Mercedes-Benz Forum

captaincrunch · #1 12-06-2002, 09:21 AM

96, E320,

There's a steady bump . . . bump . . . bump coming from under the dash. In my old 86 300SD I would say I have a leak in one of the diaphrams that control the HVAC system. Do the new cars use the same system? Has anyone else hear this noise in theirs? It's getting louder. I only hear it at idle, once RPM's get up it goes away.

IT'S ALIVE . . IT'S ALIVE!

tmorales · #2 12-06-2002, 12:11 PM

I've had it in my '97 E420 since day one. Asked the dealer to look into it and they said it was normal. However, the other day I was looking at the TSBs for my car at alldata.com, and there is a bulletin for that noise, now, that the car is out of warranty.

captaincrunch · #3 12-06-2002, 01:33 PM

That's not what I wanted to hear!

I have a hard time believing that in a $30,000 vehicle that the noise would be "normal." Sometimes I think that Service Techs will say anything instead of "I don't know."

BlueSky · #4 12-06-2002, 01:50 PM

My E320 got the same problem. I did ask the dealer.. Could not find down the problem.. Could not believe they.. not best them toyota...
that the lesson I did learn.. Will not buy the second car.. From M....Also when they hit 20000 miles.. the braker hydrolic ( spell.. may not right) not work.. hit the braker all the way down.. not stop the car.. Make me at that time.. feel to die.. Sorry to told you guy that.. Anyway just want to share the experience.

captaincrunch · #5 12-06-2002, 01:57 PM

. . . Ohhhh Kay . . .

ronald_m · #6 12-06-2002, 02:01 PM

I also hear the ticking noise under the dash it's like a heartbeat but i can't find where it's coming from.

captaincrunch · #7 12-06-2002, 03:18 PM

How do we get Donnie to give us "professional" opinion about this? It seems that this is a common problem.

I'm going to try to do a search to see if there have been other discussions on this . . . but what do I search for? Bumping? heart beat? "It's Alive!"? "Dumb noise under the dash? . . .I don't know, I don't know . . .

#8 12-06-2002, 09:45 PM

When i first bought my 84 380se the hvac would not blow hot air
traced problem to water flow control valve. Replaced guts in valve
and got hot air but then i noticed a thumping noise while sitting still and no other noises out side car. If i remember correctly it was coming from the the valve and or electric water pump for hvac
Since it isnt very loud at all i never worried about it and hvac has worked fine for the last two years "knock on wood" lol. But im driven a totally diffrent machine the you guys.

Gilly · #9 12-07-2002, 01:03 PM

Is it possible that the noise is from under the hood? With the engine running and warmed up, pop the hood and see if it's coming from the drivers side. I'm thinking possible you hear the purge valve cycling? Very noticeable with the hood open, may be transmitting to the interior. If they get too noisy, it may need a new purge valve.

Message to BlueSky: What?

Gilly

#10 12-07-2002, 01:23 PM

My 95 E320 does it too, only when the heat is on though. I've been all over that system and I can't find what is making the noise. I guess over time I just got used to it. Very weird though, I thought my car was the only one, guess not.......

Dale

#11 12-07-2002, 01:48 PM

I just looked at all of the TSB's for my car and no where did it mention this problem. Anyone else got any ideas?

Dale

tmorales · #12 12-07-2002, 04:34 PM

TSB# 154: DDAF83_30-U-160APR 97
Found this on alldata.com for my '97 E420. It is titled knocking/humming noise at idle with A/C on.

#13 12-07-2002, 04:36 PM

Mine only does it with the heat on, it's quiet when using the A/C. Do you know what the TSB says?

Behind the Star · #14 12-07-2002, 10:40 PM

Jet,
I'd be willing to bet that your noise is the monovalve. Does it sound like its coming from in front of the glove box? I had one of these kick my butt when I worked at the dealer and finally I replaced the monovalve. This still did not fix it but it was clearly the monovalve. My shop foreman had me mask the noise by stuffing insulation between the glove box and heater case. I didnt like the idea and wanted to FIX it, but he was the boss.

Brian

#15 12-07-2002, 11:20 PM

The noise comes from the center vent area, I've really got used to it and would only look into fixing it if it were a fairly easy job. I just chalk it up to mercedes ownership:p

The annoying problem that I would be more interested in fixing, and would spend the time with is the thud/clunking noise that comes from the steering box and left front of the car when I hit a bump or go over railroad tracks. Now that one I would be very interested in getting to the bottom of.........

Dale