Just bought a CLK 430, beautiful condition, however, I gave it a 3-stage buff with the rotary, turned out beautiful. Drove it about an hour both ways on christmas, ran flawless, but it was heavy rain, the next day it was clear, so I washed it down to get the luster back, I also jacked it up on the passenger side to check ball joint wear as there is a slight clunk over bumps when going slowly... As I jacked it up on the passenger side, there was a steady stream of water that came from under the car, at the firewall towards the driver side of the car, didn't think much of it. When I opened the car it smelled kind of like coolant / antifreeze. I felt around the footwells, under the carpet, even the foam, was all dry. Heater works, smell doesn't come from the vents, no loss in coolant that I can see in the expansion tank, no film on the windows, can't figure it out. The drain on the passenger side under the hood was clogged with debris, cleared that out. Smell is on the passenger side for sure, but nothing feels wet at all. Is this possible considering the water stream when I jacked up the car? There are no leaks under the car besides when I jacked it up and the residual from washing it came down. Also, there was no play in the ball joints, control arm bushings, or the like, in fact it all looked and felt new, can the steering box bolts that need to be torqued cause slight clunks? Motor mounts needs to be done for sure, can that be a cause..... Not worried about that so much as the smell, car also runs 80 degrees, little warmer in traffic. Pulled the cabin filter, bone dry, no water anywhere around that area was damp at all.... Any ideas? Do these cars have heater core problems? CA car and only has 78K on it, was dealer maintained. Funny enough, the two other CLK's I test drove, W208 and W209 smelled similar in heavy rain.

 

You should post in the W208 forum - 430 is a W208.

 

Regarding the antifreeze smell, I can only suggest a leaking heater core. I think mine might have a very small leak as my windows fog up relatively easily after rain or in humid weather, but I have no film or smell so I'm leaving it until it more symptoms show up linking that to the heater core. That said, I'm sure any car 10+ years old can develop HVAC problems so I wouldn't put it past that it's the core. Also, are you sure your passenger footwell isn't damp? Lots of guys on here have had issues with debris clogging up the rain gutters (not certain which ones as I'm not super familiar with the coupes). Obviously, this probably isn't connected to your antifreeze smell but perhaps when you jacked the car up you jolted it enough to clear the debris and hence, the stream of water.

About the clunk, I can only think of ball joints or worn sway bar bushings, possibly lower control arm bushings. Check the bushings on the actual bar itself as well as the end link bushings (we don't have actual links on our cars). I'd use a prybar to double check.

 

I'm positive there isn't dampness, I've also placed plastic floor mats over the area that would trap any moisture evaporating during the night and nothing. I'm starting to think it's just a musty like smell, my windows fog up normally, nothing more or less, the moisture has no taste to it (yes, I taste test) and is not greasy, nor does it leave a film. I'm leaning towards it not being a core issue, especially since the smell goes away when driving, even with the a/c pump turned off. I believe it's residual moisture in the system after driving. As for the ball joints, could very well be, I tugged pretty hard and checked all the bushings, surprised to see that there are no end links. I'm not going to worry about the small issues, I usually try to find things wrong that end up being ok, I know for sure motor mounts need to be done so I'll focus on that, and doing the comand retrofit. Thanks for the reply though, I appreciate it!