E320 smoke on start up
 

1998 one owner with 55K miles and all records when I bought it 6 months ago. I've only put 3k miles on it due to weather. Car starts and runs fine but has put out a sizeable amont of smoke, on cold start, the last two times I've started it. Car never smoked before.

First, make sure it's not just steam from the cold weather. Cold starts in our recent weather put out a white cloud that is more noticable than any other time.

If it's not steam, it sounds like bad valve stem seals, though this isn't a systematic problem for this engine. If the valve stem seals are bad, you should also experience a puff of smoke when taking off after a red light.

This was a healthy cloud that hung in the garage and smelt of petroleum. Don't valve guide seals fail gradually over time/mileage?

Sure they do, but 55K is rather early, unless you're driving a 3.0L Misubishi engine, like I had in my LeBaron!

One other thought is that your transmission modulator may have a leaky diaphragm. It's an easy check - disconnect the vacuum line at the modulator and see if it's wet with transmission fluid on the inside.

Since this just started all at once and the amount of smoke is cosiderable, I think the modulator is more likely the cause than the seals.

What color is the smoke? Valve stem seals leave a dark blue cloud because oil is buring off. If it is valve stem seals it should do it on almost every start up where the car has been sitting for a few hours.

If it smells like gas I can't help you I am not sure what would cause that. Maye sitting for a long time?