Whenever its cold outside and I go through a touchless car wash, there is steam coming through the grill for few minutes. Is this normal? I have not seen this happening to any of my other cars.

 

Internal combustion engine: combusts internally. Combustion means fire. Fire is hot. Pretty much like a grenade going off, or more accurately, a molotov cocktail (you know, beer bottle third full of gasoline, lit rag stuffed in the mouth, throw it? You don't know this? You will, come the revolution).

Motor gets hot from grenading. Water hits it. Heat pulls water into vapor. You see this as steam.

Grill is open and right in front of hot motor (got 6 grenades going off continuously). Water which hit motor and hot parts, turned to steam, escapes through open grill.


This will be on the test.

 

WTF? How is it anything like a molotov?

Anyways, yes, it's perfectly fine. The water from the touchless wash probably came in contact with your engine block which is very hot. It will cause the water to vaporize causing the steam. Nothing to worry about.

 

I understand the concept.
I haven't seen this happening on any other cars. I'm wondering if it also happens to other w204 owners.

 

Well what type of touchless wash did you get? Did it have an undercarriage wash? If it did, that's probably the most likely cause.

 

Gas vapor and oxygen, with the flame as igniter. Touches off the vapor over the liquid gasoline, and touches off the air fuel mix rammed into the cylinder. Oxygen is the accelerator, gas is the source of the vapor, the only thing that burns. Functionally speaking there is small difference between an electric spark and flame in this situation, because the chemical and physical result is the same.

Grenade: ignited fuse reaches explosive (powder, plastique/C-4, whatever) which burns directly, causing rapid expansion of gasses which fragments the casing holding the whole shebang; a somewhat different process. Still goes boom, though.

 

+ 10 internets for you

 

to both of you.

 

are u part of a bomb squad or special weapons expert? impressive knowledge

 

No, I've been around some, have military experience during wartime, also know a bit about the principles of car motor function, used to build a few just for the experience. I have an inquisitive mind.

What I wrote was a bit tongue in cheek, but as accurate as I could make it. Give yourself time, you'll pick stuff up too, but hopefully, not about wartime stuff. Nobody needs that kind of knowledge.

 

I hesitated to answer you here because I was hoping for more folks to say they actually have seen this on a W204 (we've all seen this with other cars, I'm sure), because I don't remember seeing this on my car, and I have it washed every Sunday, rain or shine, also in a touchless process. But that doesn't mean what you've seen is something out if the ordinary. Maybe somebody else will answer.

 

OP, it's normal. It happens when I take my daily driver through the touchless when it's cold outside.