idf

Hey all, not sure what this might be:

Went out tonight to run an errand... roads were empty so I thought what the hell, let me have some fun.

I ran the car pretty hard, and I got a TON of smoke out of the back soon after. I got home, let the car idle a while and it continued to smoke, but did taper off somewhat.

The smoke was more steamy than oily. Had that slightly sweet smell. The coolant level was fine, no other issues. Car seems to run strong and smooth.

Didn't happen at startup, nor has happened before that I noticed.

I did accidentally run out of gas a few days ago, could be unrelated.

Any thoughts on the culprit?

mishar

Sweet smell would be coolant, so cylinder head gasket. It would blow gases into coolant and you can see bubbles. If there are no bubbles in the coolant it could be injector stuck opened. Don't drive or let it idle like that.

Doc_A8

Not that Mishar needs a +1 on his diagnosis, but...... "what he said.."

white smoke is almost always coolant (unless you have just done a sea foam treatment).
Dark colored is almost always oil or running WAY too rich.....

MP4.2+6.0

+2. Also watch the other side of the coin. If coolant is going out the exhaust, it will be dropping. Keep track of the level and see if you can confirm. Check at cold each time to get consistent level. Also, open oil filler cap to be sure there isn't an oil water emulsion in there. If out the exhaust, probably not in the oil, but just in case.

TFT

Though a totally different car, my son's 2012 Elantra had that same issue with massive amounts of white smoke on hard acceleration after travelling at a steady speed for an extended period of time. It turned out to be a common problem with the Elantras, a build up of moisture in the cats.

idf

Interesting observation for a few reasons.

First, thanks everyone, it confirms my suspicion about a potential worst case.

Let me add some new info to my issue and see if it starts to change the math.

I started the car yesterday and got a solid puff of smoke, then it basically disappeared into a thin wisp after a second.

The ends of the exhaust were a touch oily. I could see drops of water had formed at the lip of the exhaust. Didn't seem to have coolant in it.

Coolant level has not changed. Oil cap removal shows no signs of emulsion.

I drove normally for a few miles, the light wisp from the exhaust continued.
Later in the day, I drove it again and had the same issue, but it seemed to be slightly less. On the second drive, I ran the car hard a few times to see if I could get the same result as the massive smoke trail I originally reported, but couldn't, though I didn't push quite as hard.

Another fact: recently I ran out of gas (I know, old age). Because of cost, I usually use mid-grade. I filled it up with premium after the event, I don't know why, but figured the extra umph would clear any trash in the system out from running dry.

So, germane to the post I quoted, I wonder if it's possible I shook out a bunch of junk when I ran the car hard coupled with higher octane fuel? I usually drive it carefully, I really hammered it that night, so I hope this is a realistic possibility?

Thanks for the support on this so far.

Jack88

What gets me still is the slightly sweet smell you initially reported. Coolant is the only thing I know of that can give you a slightly sweet smell. I still would say to keep an eye on your coolant level. Moisture that collects on the exhaust tip is likely condensed water from moist exhaust encountering cool outside air, and as such wouldn't necessarily be anything other than water, even if coolant was being burned.

CWTech

In cars here are general rules:

White smoke = burning coolant/moisture
Blue smoke = burning oil
Black smoke = running rich

If there was a lot of moisture in your exhaust system from condensation or something, it's possible that's what was giving you white smoke but that should disappear pretty quickly (within 5 minutes) and then be gone.

I suppose if the fuel was tainted with water or something, that might also produce white smoke from exhaust, but the car would be running like ****.

My suggestions is to drive the car normally for at least 30-40 minutes, preferably on the highway, so that the exhaust can get up to full temp and burn off whatever might be in the exhaust. From that point if you continue to see white smoke, you need to start finding out where your problem lies.

Greybeast

Doc, I wanted to Seafoam my engine. On others I typically unplug a brake booster hose and drizzle it in. I peeked under the hood and around the booster. Too much crap to locate the brake hose. If you've done yours, what's the method?
Mike

dvs_dave

Has the car been power washed or been driven or parked in axle deep water recently? Could be something as simple as the exhaust having an excess amount of water it it that steamed off when it got hot enough.