tokey

Has anyone seen this?
I've had 3 dealers look at this.

Problem is when the A/C has been running for a while and i've driven for a while, water leaks down (as normal) but it some lands on the pipes making a "sizzling" noise. Similar to if you put water on a hot stove. They all say this is normal but i've never seen this before in any other car and i find it hard to believe that i would pay all of this money for a car that has this happen to it. I've insisted they check all and they say everything is how spec'd.

Diesel Benz

I've never noticed the same. Is your exhaust system original? Otherwise it should be just about the condensed water drain pipe. I'd check myself how it is fed. Perhaps some panels misplaced?

tokey

Yes it is original. The dealers all said the drain is in the right place. I'm going to take to another one to look at it detail... Misplaced panels? That sounds like something i will mention.

Thanks

Diesel Benz

Perhaps you should mention the engine model you have. I'm not sure if it makes a difference between those models that are available in the US but my exchaust pipes must be routed a bit differently from V8 and V12 engines because the engine has a single turbo charger even if it is a V-shaped engine.

If other owners with the same engine have not faced this issue, I'd put some pressure on the workshop to fix it.

Joe S

Of the many cars I owned during my life time with A/C I never had that happen-ever. You might want to place a call directly to Mercedes regarding this issue.

azizblue

hi do have this problem in my car. s63 amg.is that nurmal .is this a recall are what

RA032924

In addition to the normal hissing noises from the suspension, I too noticed the sizzling noises from the a/c condensation on my 07 S550 - built August 2006. My only thought was that I live in a high rise and drive up several levels to park the car, which is when I really notice the noise (maybe dripping at some funky angle). I'm 3K away from the end of the warranty and would appreciate anything you discover from your own trouble shooting or dealer resolution.

Diesel Benz

Are you specifically referring to the noise from under the car, water dropping on to hot exhaust parts? The evaporator and other AC parts make some similar noise by default. After all, cooling power is produced by making the compressed gas "vaporize".

If the water from the AC core drops directly on exhaust pipes, it should be pretty easy to move the hoses or extend enough to feed the water away from the exhaust pipe.

emilner

I had it happen for the first time yesterday after a long 130 mile drive. Under the passenger side firewall area I could hear water sizzling off the exhaust for a minute. It doesn't concern me much, but I will see if it happens again...

Diesel Benz

Would be nice if you had a chance to look at the car from below if there is an obvious explanation how the water hits the exhaust pipes. Sounds like it does not directly drop from the AC hose but the water gets collected on top of the panels while the car is driven?

emilner

Yeah, it sounds like it is collecting somewhere. It has not rained in days and I drove 130 miles without being near water so it must have come from the ac. It doesn't bother me, I first have to see if it happens again...

451/443=EW

To me it sounds very normal. Iv noticed this sound on many cars. Even on my 1993 Mazda B200. Its simply the condensation from the AC unit dripping and landing on very hot parts. Post this question on the other sub forms. Im sure that once guys start to listen for this, it will appear to be much more commen then you realize.

Just so I got it right... the sound is coming from under the hood right?

Diesel Benz

Cannot be AC condensation water if the noise comes under the hood, the hose must be going down further to the rear of the car (about under the HVAC core)?

I would not bother either and would not be concerned if it was just some water hitting the exhaust as long as it isn't from a misplaced drain pipe from the AC core where all of the drain water would hit the exhaust.

moayes

Hi there,
I don't know anything for sure about your car, and as far as I know about my car, it's a W210, the drainage pipe of AC is directly over the exhaust / drive shaft going from engine to rear wheels.
There is one pipe on either sides - one on the left, one on the right - its somewhere behind the center console, few inches behind the passenger / driver foot air outlet toward the engine.
I have tested mine and seen it; when the AC works, water comes off the drain as a stream!! it's not drops of water... it's really a stream of water. It looks as if you have opened a faucet. That's why the water streams on a hot surface to evaporate and the excess falls on the ground (it might have also some cooling function; though, I'm not sure).

cityvic

I have the same problem with my 2008 CL550. I took the car to the dealer and they told me nothing could be done. When my car was on the lift I was able to see exactly what was happening. The condensation drain tube is really short and just above the exhaust pipes. There is a metal pan that allows water to accumulate just above the pipes.Depending on the angle of the car, water drains from the pan onto the hot exhaust pipes. If the drain tube was extended by 0.5 inch, the water would drip below the pipes. I am not sure why a longer drain tube can not be installed. None of the dealers are willing to touch it.

Carters550

I have contacted mbusa and the said its specifically designed to drip on the hot exhaust ... this way it vaporize it right away ...preventing the driver from seeing water pools or water under the car and freaking out .....acording to mbusa it's supposedly better for the environment ...here you have it

brownbomber

I have had the 07 and 08 w221 vehicles, and both have made that same sound after running long enough to get hot. I have charged it off as being normal. I have also posted threads inquiring about this same issue, and gotten no responses.

dcm95ss

My s63 does the same

markg612

I realize this is an old post, but my 2012 S350 BlueTEC does the same thing. I went under the car to investigate, and now believe it's a design flaw in my opinion. The HVAC drain is directly above the exhaust line, which is OEM original from the factory.

When I first got the car, I thought it was on fire from the rising steam. My first cursory inspection lead me to believe it could be leaking DEF because the emitter is right there but as it turned out it was the HVAC drain, no different than the other models sighted above.

The HVAC evaporate drain drips directly on the exhaust pipe, period. Geez, you think a $100K plus vehicle wouldn't have a nitnoid flaw of this kind!