Exhaust smoke isn’t always a four-alarm fix


Dear car speech:

I drive a 2013 BMW X3 It’s a great car, maybe the best I have ever owned. He only has 52,000 miles.

I retired six years ago and drive a lot less than before, let alone during the pandemic. Recently it has started to sporadically emit a lot of exhaust smoke on start up, enough to fill the garage. Not every time, but especially when left unused for a few days.

When I asked the dealership’s service department about this, I was told that older BMWs had this problem when they were left unused for a few days, and there was no other solution. than a new engine. I guess they were suggesting that I buy a new car. Of them.

Seems unreasonable for a 9 year old car with low mileage. At my age, I don’t need a new car and was planning to keep this one. No advice?

– Tim

Advice? Yeah, make sure you always open the garage door before you start the car, Tim.

And keep driving. There is no reason to install a new engine there based solely on this problem.

We see a lot of cars doing this. The most likely explanation is that oil remains on the cylinder walls after shutting down the engine.

And in your case, it is possible that a little more oil will leak out of the valve guide seals and into the cylinders while the car is seated. Then, the next time the car is started, this oil is burnt and comes out of the tailpipe as smoke.

It doesn’t smell good and has a blue-gray haze that makes you feel like you’re living in Los Angeles in 1974. But keep in mind, Tim, it doesn’t take a lot of oil to make a lot of smoke. So don’t assume you have a major problem.

As long as you’re not losing oil at a significant rate, it’s really more of a nuisance than a BMW four-alarm repair. The key is to keep tabs on your oil intake. If you add a liter every 1,000 to 2,000 miles, it’s not bad enough to be fixed.

If you have to add a liter every 200-300 miles, you’re burning a lot of oil – and that doesn’t just happen when you start the car after a few days. In this case, the dealer is right. You need serious engine work. Or a 2022 X3, with a Harmon Kardon stereo and 19-inch alloy wheels.

But the phenomenon you’re describing – burning some oil on the first start after a few days of rest – isn’t something we’ve ever correlated with impending engine failure. In fact, he could have done it for years. Until recently, you rarely let it sit for three days.

So watch your oil consumption, and if it’s not alarming, keep driving, wave the dealership, and smile every time you walk past.

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(c) 2022 by Ray Magliozzi and Doug Berman
Distributed by King Features Syndicate Inc.


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