Steam & Smoke after Carwash

[EricSilver]

After taking my 89 260E through certain automatic car washes, I notice steam
and smoke coming out of the exhaust for a few minutes, then it stops.

It seems that water is getting into the exhaust system somewhere, and mixing
with oil residue to cause the smoking/steaming. This started a couple of
months ago after I got new tires -- and drove the car off a lift which, I
discovered when I felt the scraping under the car, was not completely
lowered. Is it possible some part of the exhaust system or catalytic
converter is loosened or cracked and allowing water to get in?

This only happens when there is an undercarriage wash. When I wash my car
myself, and spray water up the exhaust , there is no smoking.

Any help would be appreciated.

Eric Silver

[jeffsr]

Eric, what you are seeing is condensation created inside the exhaust system when it gets rapidly cooled from the undercarriage getting soaked with water. Condensation will form inside the exhaust from rapid cooling and then reheating will blow it out. Not to worry, if you had a hole large enough to let that much water in, be assured, you would certainly be hearing it.

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Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 05-24-2000).]

[EricSilver]

Jeff, thanks for your reply. I figured it was something like that but was never quite sure.

Now that I think of it, the smoke/steam only appeared when the car had been hot. On those occasions when I washed it just after starting it for the first time in the day, or after it had been sitting for a few hours, there was no smoke, so your condensation explanation makes a lot of sense.

The only problem is that it is embarrasing to be spewing smoke like that -- even for a short while. Other drivers seem to get some sort of perverse thrill from seeing a disabled or malfunctioning Benz.

Thanks.

Eric

Eric,

Whatever you do, don't spray water in your tailpipe ever again.

Good luck,

------------------
Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

[jeffsr]

I second Larry. I didn't catch the last part of your post. NEVER spray the hose up the tailpipe. You will ruin the exhaust system real fast that way. Also, if you get liquid into the cat, kiss it goodbye...

------------------
Jeff L
1987 300e
1989 300e
1987 BMW 325

[EricSilver]

Larry/Jeff,

Thanks -- I did not spray it directly or deliberately. Just in the process of rinsing the car, it is unavoidable that some water gets into the exhaust pipe. Apparently, that small(?) amount is not enough to cause any harm.

Thanks for the advice nonetheless.

Eric