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Discussion Starter · #1 ·
I let my SL sit for a few months and now whenever I start it up after it sits for a few days, it emits a lot of white smoke from the exhaust. After a few minutes it stops smoking and runs fine. What would cause this?
 

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'09 E350 4-matic sport, '83 240D 4-speed (sold), '77/'78 450SLC (junked), '81 500SLC (junked)
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I let my SL sit for a few months and now whenever I start it up after it sits for a few days, it emits a lot of white smoke from the exhaust. After a few minutes it stops smoking and runs fine. What would cause this?
Change the oil and filter and then report back. I tend to hope it's just condensation in the oil, but it could be a leaking head gasket. A similar thing killed my 78...

Smoking on startup could also be valve stem seals, but that's typically a greyer smoke...
 

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I changed the oil yesterday and it did it today. I don't see anything that looks like water getting into the oil. By the smell of the smoke, I thought it might have had some antifreeze in it though. But wouldn't I get water in the oil?
 

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'09 E350 4-matic sport, '83 240D 4-speed (sold), '77/'78 450SLC (junked), '81 500SLC (junked)
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I changed the oil yesterday and it did it today. I don't see anything that looks like water getting into the oil. By the smell of the smoke, I thought it might have had some antifreeze in it though. But wouldn't I get water in the oil?
I had water in my valve covers and water in my cylinders but no mayonnaise in my oil pan. There was peanut butter looking stuff under the valve covers. Taking your car in to get the coolant tested for combustion products might be a good next step. They sell a funnel that seals onto the top of your overflow tank (where the cap normally goes) that will let you see if exhaust gasses are getting in to the cooling system (it'll show up as bubbles), but I've never used one so I don't know how sensitive they are to small leaks.
 

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2010 Mercury Milan Hybrid, 1993 BMW 325i convertible
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I changed the oil yesterday and it did it today. I don't see anything that looks like water getting into the oil. By the smell of the smoke, I thought it might have had some antifreeze in it though. But wouldn't I get water in the oil?
A leaking head gasket can leak coolant into the cylinders and you won't see it in your oil.
 

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All these cars tend to mark their territory...You may have a tranny fluid leak that is finding its way into the exhaust...I had a rear transmission seal go bad and the fluid was flowing into the exhaust. Looked like the Bat-car had let loose with the Bat-fog. A small leak might cause the white smoke for just a short while after startup.
 
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