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Huge Plume of Blue Smoke Billowed out When Starting Engine

101K views 279 replies 71 participants last post by  AscentForumUser 
#1 · (Edited)
After the first few days of driving the car and with less than 200 miles on it, I drove into my driveway and went into the house. After about 5 minutes, I got back in the car and started it to drive away. I was immediately engulfed by a huge cloud of blue smoke that I presumed came billowing from the exhaust. I immediately realized that this was MUCH more smoke (it was as if I had just started a finicky cold diesel engine) than ANY car should ever give off. It was more smoke than any other car I have ever seen give off unless it was on fire. I immediately got out of the car (still leaving it running as I didn't think to push the button to stop it) fearing it might be on fire. When I looked toward the back of the car, I could hardly see it through the smoke. Looking at it from 10 feet away, it appeared that the smoke was coming from under the car. I never saw a flame. It looked like when you put a large pile of dry leaves on a fire. It starts to smoke A LOT, then the flames erupt and the smoke disappears.

Within about 30 seconds, the smoking subsided and stopped. The car never made an unusual noise. I didn't have any dealer applied undercoating applied as I though that might have caught fire. Then I considered that the turbo might still have had hot oil that got shot into the engine or exhaust system. This did happen after having driven the car for 30 minutes, shutting it off and restarting it 5 minutes later. (I have keyless start so no manual gas was applied.) I have no idea what caused the event. I'll bring it up to the dealer when I see him next (although they don't want to see us for 6,000 miles).

So here's a heads up for any of you new Ascent owners. Normally, there is NO sign of exhaust upon startup. If it looks like a large pile of leaves just got lit under your car when you start it, you will have just joined the club. I would recommend to get away from the car.
 
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#2 ·
It's an inherited problem on flat/boxer engines, particularly on Porsches with improper functioning air/oil separator at cold start. People on here said that these engine do not have air/oil separator but rather use a simple check valve(s) called PCV (common device on non-boxer engine). Worst, if the piston rings are allowing oil to seep thru when the engine is at rest, you'll have smoke at cold start. If you're handy, you should do some inspection on the PCV to rule out the problem.

I don't believe it's the turbo unless the seals are shot already.

If the problem persist and gets worst, you should take it to the dealer. At this time, you should call your dealer and report it.
 
#3 ·
I'm not taking any chances. I won't park this car in my garage. I won't even park it near the house right now. It's about 10' away from the house. If there's a 1 in 1,000 chance that the car will start burning up or explode (it does have a 19+ gallon gas tank), I'm not going there.


On the plus side, when I contacted my dealer, Reynolds Subaru here in Connecticut, they sent someone immediately to PICK UP the Ascent where I work and left me with an Outback loaner. That's a class act.



BTW, this was not a cold start. The engine had been running for at least half an hour, then turned off for about 5 minutes, then turned on again when this happened.
 
#66 ·
I just had my 2019 ascent did this an hour ago. I always park it on an inclined driveway at work. Never had this issue til bow tho. Billow of smoke seemed to come out from undrneath with a burning smell. It got me worried for a bit but it went away after a minute. Bottomline WHAT THE HECK WAS THAT?!!
 
#12 ·
Our car is only a month old with 1100 miles on it and I experienced the thick smoke out of my tailpipes today. I've already dropped it off at the dealership to have it looked at, and will follow up with what they find, in case anyone experiences the same issue.
Maybe loose turbo bolts? Is your VIN in the 6,000s?
 
#18 ·
I’ve had my Ascent blow white/blue smoke on two startups (2,300 miles now). They both happened on warm starts after sitting for 10-15 minutes.

Was never overly concerned as I also own an air cooled 911 where Smokey starts are fairly common after sitting for longer periods of time(2-3 weeks in my case). I thought it was a horizontally opposed thing but watching this thread closely to see how things develop.
 
#20 ·
I'm sitting and waiting for a tow truck to come and pick up my 2 month old Ascent with 4000 miles on it. I took it to the dealership last week for its first oil change and drove it through the weekend with no problem. Yesterday morning, however, when I started the car (cold engine), I got a thick white stinky exhaust that lasted about 30 seconds and then cleared up. It happened again at lunch time (after the car had been sitting for 5 hours) but wasn't as dense. This morning, it was even worse and very smelly. Lunch time today, I thought something was on fire......this time it didn't dissipate and definitely had a burning smell to it. I even drew a crowd in the parking lot of my office. I shut off the car and and am hence waiting for the two truck.....
 
#22 ·
I'd be interested in knowing what trim level and what dealership.
 
#21 ·
Oh, @Lopaka. I feel so bad for you. I wish we knew each other better. I am sure you found out about this forum well before today. You could have created an account long ago talking about vehicle comparisons ans such. You were so overjoyed when you bought it, you created a thread with pics in it. You had so many journeys with the Ascent in the past two months you had more threads and pics. I mean, above average mileage in 2 months warranting an early oil change. But since you didn't, I am glad you came here to warn us of the ticking time bomb in my driveway.

As far as resolution to your problem, maybe you can post your service order? We can review what the service dept did. They may have forgotten to tighten some bolts when replacing the muffler bearings causing a leak? Did you check to see if there was a banana or two in the tailpipe? I have neighborhood kids who have been known to do such a thing.

Let us know how it turns out. Maybe it can be something to look forward to. I can blame my recreational habit on the car!
 
#25 ·
You away on a road trip?
 
#27 ·
Newer cars boil off water that condensed in the exhaust system overnight. The Ascent is no different. The cleaner a car's emissions are, the more water vapor or water.

Some cars have cool enough rear exhaust that instead of steam, they drip or even pour out water.

Keep an eye on the NEWER cars in front of you on the highway in the mornings, and you will see one or the other. Or a combination of the two.
 
#59 ·
Newer cars boil off water that condensed in the exhaust system overnight. The Ascent is no different. The cleaner a car's emissions are, the more water vapor or water.

Some cars have cool enough rear exhaust that instead of steam, they drip or even pour out water.

Keep an eye on the NEWER cars in front of you on the highway in the mornings, and you will see one or the other. Or a combination of the two.
A recent article in automotive news regarding Subaru quality issues attributed ( according to Subaru reps) the engine smoke to "oil dilution"-- NOT moisture accumulation. On facebook one individual posted a video of the excessive smoke and said Subaru is replacing his engine. I'm now second guessing my decision to purchase a 2020. Mine now had only 54 miles on it.
 
#28 ·
Well, I just heard from the dealership; they are claiming that they did overfill the oil during the oil change from last week. They could not explain to me why the problem (the smoking) did not appear until 5 days after the oil change was performed. The woman I spoke with did state that the oil apparently accumulated in the exhaust system which caused the problem. I guess that sorta makes sense if you figure that it would take some time for the oil to accumulate enough in sufficient quantity to cause a problem (?!?). Anyone have any thoughts? Thanks.....
 
#34 ·
Good News!!!! NORMAL!



Hi, as mentioned above, that is absolutely normal. Your car will burn off condensation when cold. Newer cars have FAR more water vapor as exhaust because they burn cleaner. Depending on exhaust length, outside temperatures, exhaust temperatures, etc, it will come out as thick water vapor, or as water running out the rear of the exhaust, or both.
 
#36 · (Edited)
But of course...



A lot of it is temperature and humidity dependent.

As for the smell, a couple reasons come to mind...
  1. Cars burn less clean when starting (which is related to #2 below).
  2. With the car off and cooling, as well as when just starting it before the catalytic converter hits 400°F+, it's not trapping and catalyzing as much exhaust waste - instead, that is coming out of the tailpipe until the system heats up.

#2 is part of the reason why they do various emissions tests on a warm car after the catalytic converter has reached operating temperature. A catalytic converter starts functioning between 400° and 600° degrees F. The normal operating temperature can range up to 1,200° on a properly operating car (higher in a poorly functioning one - but that would throw a code and CEL on a Subaru).

So, when you start your car, even let's say in Nevada in summer at 100°F, you have quite a while before the cat gets to minimum operating temperature, much less normal operating temperature.

To summarize:
In all cars with cats, the exhaust fumes will be smellier when first started. Various environmental factors, mileage, type of vehicle use affect how smelly and for how long (eg: heavier loads, or brutal beach driving causes "dirtier" exhaust). And, newer, cleaner burning cars collect more condensation/water/vapor over night or after driving, which burns off when the car is first started. Depending on outside humidity, and how much collected, and how quickly the cat heats up (and how quickly the muffler and tail pipes heat up in relation to the cat), one will see more or less or no steam or water vapor or water come out of the exhaust.

Here's a few neat articles on catalytic converters, operating temperatures, their purpose, etc:
 
#38 ·
I guess I have joined the club

Here are some photos of my smoke. Started after 1st oil change. Dealer has changed the oil again as per our request but problem continues. It only happens when car is parked on an angle with the passenger side facing downhill. Dealer has had the car for two weeks and is still waiting on Subaru to tell them what to do next. To my knowledge, nothing has been done to the car, not even diagnostics or emissions testing. It’s just sitting there. :sad:
 

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#39 ·
Normal...

Here are some photos of my smoke. Started after 1st oil change. Dealer has changed the oil again as per our request but problem continues. It only happens when car is parked on an angle with the passenger side facing downhill. Dealer has had the car for two weeks and is still waiting on Subaru to tell them what to do next. To my knowledge, nothing has been done to the car, not even diagnostics or emissions testing. It’s just sitting there. :sad:
That's steam and morning burn off. That's normal.
 
#40 ·
I think they might be looking for a reason why its so prominent after parking on an incline and why it would've started after their first oil change.
Is it just the location where more moisture may be concentrated on the incline? Maybe its just a coincidence that it started after the first oil change or maybe theres some other variable unaccounted for...
My driveway is on a slight incline but I'm always facing uphill. I'm temped to park sideways to see if I can recreate it on my car.
 
#42 ·
We have parked the car in various ways to video the exhaust. When the car is sitting level or when the drivers side is facing downhill, we get no “smoke” whatsoever. Only when passenger side is downhill. It seems to be more in quantity after the car has been driven, then parked that way for a few hours. The second time it happened, we thought the car was on fire, but the smoke seems to stop after about 5 seconds.
I don’t know if we should leave it with dealer service a bit longer or go get it and just keep a record of how it behaves. At least we have it on file with Subaru as the service manager is in touch with their tech line.
 
#43 ·
We have parked the car in various ways to video the exhaust. When the car is sitting level or when the drivers side is facing downhill, we get no “smoke” whatsoever. Only when passenger side is downhill. It seems to be more in quantity after the car has been driven, then parked that way for a few hours. The second time it happened, we thought the car was on fire, but the smoke seems to stop after about 5 seconds.
...

Ditto for me... this was the only time I've seen it (parked across the grade, passenger side downhill on like 3%+ grade). Just a second or two... oil level is fine... everything is fine. ;-)
 
#44 ·
We picked the car up this morning. Subaru says it’s normal under certain circumstances. Dealer service was great to work with, their hands were just tied until SOA decided what to do. They are asking that we do an oil consumption test. We are to return to the dealer in 1200 miles to have the oil checked, or sooner if we notice low oil or the oil light comes on.
Thegeeknme, I would be curious to know if your smoke started after the 1st oil change. Still wonder if turbo should be using 5w-30. I know SOA says no, but why is it recommended in their other turbo cars?????
 
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