Occasional Blue Smoke

[David H]

2017 5.7 20k Miles 5K mile oil changes 5-30 syn Has catch can.

I occasionally get a blue cloud on start up. This only happens after a short run cycle (30 seconds) like when I move the truck out of the garage to make room. So half the time, after a short run cycle like that, the smoke will appear on the next startup.
Never happens after I run it for a couple minutes. Concerning?

 

[Fast69Mopar]

2017 5.7 20k Miles 5K mile oil changes 5-30 syn Has catch can.

I occasionally get a blue cloud on start up. This only happens after a short run cycle (30 seconds) like when I move the truck out of the garage to make room. So half the time, after a short run cycle like that, the smoke will appear on the next startup.
Never happens after I run it for a couple minutes. Concerning?

Blue smoke is oil burning in the combustion chambers. There are only a couple of ways for oil to reach the combustion chambers and it can be from the valve seals not sealing around each valve stem properly and allowing oil to travel past the seal and on to the back side of the valve. When this happens the oil build-up is one of the first things burned when the engine is started and it burns blue.

Another way oil reaches the combustion chambers is by worn compression rings in the cylinder. The too ring of each piston is a compression ring. When these wear heavily they allow oil into the combustion chambers. When the compression rings get worn they allow pressure to be built up in the crankcase and this pressure can push oil out of seals and gaskets and past the rings into the combustion chambers.

With all of that being said, I have seen catch cans installed and connected improperly and fill the PCV system and intake manifold with oil.

How long has your catch can been installed?

Did the blue smoke in start-up start after the catch can installation?

 

[David H]

Thanks for the reply. I installed the can at roughly 1500 miles. The occasional blue puff started around 17,000 miles making the 2 likely unrelated.

Just seems odd it only does this after a really short run cycle. If I let it idle for 2 minutes after I move the truck it will not blow smoke on the next start.

 

[hemihustlin]

Yes this is very normal with the precise conditions you describe. My 06 did this regularly when doing things like moving it in the driveway or in - out of the garage. with the side exit exhaust I could see it in the mirror. Haven't noticed it on my new one so far but rear exit exhaust so probably wont see it.

 

[Bob Macknight]

PVC ?

 

[Burla]

Rare with so few miles, off chance you have a gummed up combustion chamber, maybe run sea foam through vac lines and clean it. Nothing will clean combustion chamber as good as sea foam through vac lines.

With so few miles one would expect excessive block to piston clearances, which is likely unfixable. In a perfect world this would have been addressed the first 18 mos of owning it new and 4 tags of an attempted fix, then you would be entitled to relief. Now, dimes to donuts the dealership will say it's normal, within tolerance. As the miles increase on this machine, I'd expect problems with sensors and cat. Stay with 5w30, don't go thinner, it would be worse.

Did this show up right after catch can install or before?

 

[Hemi395]

What kind of catch can do you have? How quickly does the catch can fill up on your truck? Its possible its sucking some oil in through that. With that low of miles I doubt its bad valve seals or rings....

 

[David H]

Rare with so few miles, off chance you have a gummed up combustion chamber, maybe run sea foam through vac lines and clean it. Nothing will clean combustion chamber as good as sea foam through vac lines.

With so few miles one would expect excessive block to piston clearances, which is likely unfixable. In a perfect world this would have been addressed the first 18 mos of owning it new and 4 tags of an attempted fix, then you would be entitled to relief. Now, dimes to donuts the dealership will say it's normal, within tolerance. As the miles increase on this machine, I'd expect problems with sensors and cat. Stay with 5w30, don't go thinner, it would be worse.

Did this show up right after catch can install or before?

This showed up well after the catch can was installed. Like, 15,000 miles/3 years later.

What kind of catch can do you have? How quickly does the catch can fill up on your truck? Its possible its sucking some oil in through that. With that low of miles I doubt its bad valve seals or rings....

I don't recall the brand but in the summer it's close to half full at 5,000 mile oil change...3 to 4 ounces. Winter time it fills faster so I empty it in-between changes. Probably would not fill at 5,000 miles but I don't give it that chance. Much more water in it in the winter time. Located in Minneapolis. The can works as advertised and I very much doubt it's an issue.

Thanks for the replies.

 

[indept]

Your truck is still within the 5yr/60k powertrain warranty so why not bring it up with your dealer? Of course they'll blame it on the catch can.

 

[David H]

Your truck is still within the 5yr/60k powertrain warranty so why not bring it up with your dealer? Of course they'll blame it on the catch can.

Thanks. Just not one to bring it into the dealer every time it has a cough. This seems like a cough to me and would like to avoid an interruption in my hectic retired schedule. lol
If it did this every time I started it I'd be more concerned and bring it in but it only happens when the motor is cold, run for half a minute, then restarted hours later.
I do have the extended warranty so no rush to dump it on the dealer. Thanks for the reply all the same.

 

[crackerjack1957]

Thanks. Just not one to bring it into the dealer every time it has a cough. This seems like a cough to me and would like to avoid an interruption in my hectic retired schedule. lol
If it did this every time I started it I'd be more concerned and bring it in but it only happens when the motor is cold, run for half a minute, then restarted hours later.
I do have the extended warranty so no rush to dump it on the dealer. Thanks for the reply all the same.

If it doesn't use oil & only does it on a short run crank on next start I say you have no problems.

 

[averageguy]

My 05 hemi did the same thing often with 11,000 miles on it and it was just "moved around" a lot.

 

[Smitty2495]

2019 6.4 21300 miles. 0w40 every 5k. Mine did the exact thing today. Heavier start up tap and one kinda large puff of blue/white smoke within 2 sec of start. No catch can.

 

[Iron General]

Hi guys,
just wondering, if anybody has figured out what is causing this issue?
I had the smoking problem, on my 2011 at start up occasionally. But then I found out that I had a broken valve spring, got a new one in and that seemed to solve the problem . (crossed fingers)
Just some food for though. Hope this may help someone.
Thanks for all the information. Y’all rock