This is a 380SE Euro version (graymarket) W126 chassis. It currently has 196,000 original miles on it.

I had the timing chain + guides + tensionners + water pump replaced at 160K miles. So I've put on about 36K on the new chain and tensionners etc.

I have never checked the EGR valve nor any of the vacuum system.

I tend to think the bottom end is not to blame because the smoke is so rare and intermittent. It's just that on the rare occasions that it does smoke, it smokes a lot for about 20 seconds at a time.

The car otherwise does not have any known leaks. It does not drip any oil on the ground. I do put in about 1 qt of oil every 1,500 miles or so - more when city driving, less when mostly hwy miles.