'07 5.3L AV white smoke at startup and oil consumption

At startup in the morning (and sometimes after driving less than 10 miles) I will get a puff of white smoke (Its defiantly white smoke, not blue or black) from the exhaust pipe.  After driving for 10 miles or more, I don't get the puff of smoke from the exhaust. (Like if I drive and stop at the store or for relatively long distances and restart the truck)  I do have a little bit of oil consumption however.  I haven't noticed any loss in engine coolant or high temp readings.  No loss in oil pressure and I haven't noticed any other problems either.

I've read on here (as well as other forums) that the white smoke could be caused by the placement/oil fouling of the PCV valve, coolant leaking into cylinders (leaking valve seals), leaking valve cover gasket, issues with the AFM (needs to be disabled) and other issues as well. (such as oil baffles, etc.)  I've also read that there are TSB's that describe this problem, but I cant seem to find the specific TSB for the 2007 Av. 

I would appreciate any assistance that would lead me in the right direction for a TSB so that when I take my loving baby to the dealership, I can show them the TSB (or describe the issue in detail) so that I can get this issue addressed.  Also, if there are any other suggestions for repairs that would address this issue, I would appreciate those also.

White smoke = Coolant
Blue Smoke = oil
Black smoke = gas

I'm thinking it may be a bad intake gasket or head gasket

Well, I haven't noticed any smoke lately on startup over the last few days.  I have however, been constantly checking my oil level.  (making sure that it does not get too low) I think I will probably change the valve cover with the redesigned PCV valve opening to help with the oil consumption.

Thanks for the help!

Oooooh I wish I had a white Avalanche

I have an 04 Av 5.3 with 114,000 miles.  Mine too will blow a small bit of white smoke at startup, but only after it has been driven a good distance and parked.  If for example, I start it up and move it in the driveway (engine running less than 5 minutes) and park it, the next morning I start it and there won't be any smoke.  It doesn't really have that "sweet" smell like coolant but it's not blue or black, so I guess it would be coolant?  I have about 2500 miles since the last oil change and no noticeable change in oil level at all, been checking at each fill up.  The coolant level looks to be a little bit below the "full" indicator but I didn't start paying attention to that level until about 500 miles ago, and I really can't see that there is any difference since then.  The engine is running smooth, no overheating, excellent acceleration; really no other indication that there is a problem besides the small puff of white smoke.  I only noticed it when I started remote starting it a few months ago, it may have been doing it all along, I am just not sure.  If there was a bad head gasket, what other clues are there that I can be on the watch for?  I have only owned it for about 4 months, by dad had it before that for about a year and besides replacing the knock sensors, no other engine issues.  I probably need to change the plugs and wires, but as it has been running so smooth, haven't made that a priority.  Pulling the plugs may show some additional signs of trouble, what would I be looking for specifically there?  Any thoughts or ideas would be appreciated. 

BTW I also own a 03 Chevy Express with about the same miles and the same engine, no white smoke on that ever, that what has got me a bit worried.

Ok!  So I finally got around to changing the drivers side valve cover on my '07 Av.  I've been having intermittent problems with white smoke at startup after the truck has been sitting a while and/or overnight.  I've also had a slight issue with burning oil and having to add a quart or two once a month or so.  I've read that it could be a bunch of different problems from blown head gaskets to a bad PCV valve, bad rings and so on.  I basically eliminated some of the obvious issues due to not having any other symptoms associated with those types of problems, so I decided to change the valve covers after reading up on the issue.

Apparently, starting with the 2007 Avalanches, had a design "flaw" in the drivers side valve cover.  The vent hole for the PCV valve was prone to clogging (due to its position within the valve cover) and that clogging of the hole may be the cause of the white smoke at startup.  Chevy's remedy was to redesign the valve cover to reposition the opening so that clogging was reduced.  I decided to change the valve cover to see if this eliminated my problem.  below is a description on that needs to be done if you would like to change the valve cover yourself.  Its not that hard, and if your handy with tools, it shouldn't take you more than an hour. 

Check out this link for more information on the subject.   http://www.autoserviceprofessional.com/article/91874/gm-oil-consumption-and-blue-smoke

Moderator: since this is a repair sticky, please feel free to repost this under the correct forum posting!

First, the redesigned valve cover I purchased for my 2007 Av was GM part number 12570427.  I bought it of Amazon for about $103.00.  Please check the correct valve cover for your application.

You are going to need the following items:
10MM long socket
8mm socket.
Clean rag.

First, remove the plastic cover off the top of the engine.  Make sure you don't lose the two rubber grommets that hold the cover down.

Next, reach back near the firewall and remove the PCV hose from the valve cover.

Next, pull each of the spark plug wire boots off of each ignition coil. (you do not need to remove the wires from the spark plugs.)

Next, remove the 5 long bolts with the 10mm long socket that hold the ignition pack to the valve cover.  (You don't have to remove the wires that connect to the ignition coils.)







Next, move the entire ignition pack away from the valve cover.


Next, use the 8mm socket to remove the 4 bolts that hold the valve cover.  The bolts do not come out of the valve cover, they are held in by a rubber grommet.






Next, remove the valve cover.  As you can see, my lifters don't look bad at all!


Here is a pic of the inside of the new valve cover and the old one.  As you can see, the position of the PCV vent has changed.  Also, there are really small oval seep holes at the bottom of the PCV vent channel that are clogged as well.  The inside of my valve cover doesn't show any gunk (such as oil mixing with antifreeze) so, I figure I don't have a coolant leak.



Next, use a clean, lint free rag to wipe down the edges of the heads where the valve cover seats.  Try to remove any oil or dirt to ensure a good seal.  The valve cover should come with a rubber gasket attached to it.  You don't need to use any gasket sealant for installation.

Installation is reverse of the removal procedure. Place the new valve cover on, tighten down the valve cover bolts. ( I don have a torque wrench, so I just got them down tight enough for them not to move. (I didn't want to break any of the bolts!)  I tightened the two inside bolts then the two outside bolts.
Put the ignition pack on and replace the bolts that hold it down.  Make sure you replace the PCV hose and then put the engine cover back on.  That's it!

Hopefully this will alleviate my problems!

Good write up, but not seeing any pictures.  

Reviving this thread because I just did the exact same thing on my '07 Avalanche yesterday.  Here is a couple pics I took:


Comparing new Valve cover with old one:


Valvetrain before installing new cover:


Hoping this will help with the periodic puff of smoke on startup and oil consumption.

Well after 2.5 weeks I have yet to see a puff of smoke upon start up and the oil level is still full. So dare I say that the problem is resolved? I'm keeping an eye on it.

It's been a few years. How did this work out for you? I have the same issue on my 08'.

Well for me it's been 6 months, and I have not seen any puffs of smoke at start up. Oil consumption is way down, about a 1/2 qt every 1000 miles.

I'm pretty sure my 2007 needs this head replacement done also same issue you described. Plan to replace this upcoming week.

Did the modification & Did cut way down ammount of oil pulled into fuel/air system.
Today I'm checking the afm plate bolts underneath intake manifold, didn't want to remove but luckily I did 8 of the 11 13mm bolts holding the oil pressure for afm were finger loose turned loose all but 4 bolts with socket & fingers.
Tight ones I left & torqued center outward side by side evenly press back down oil seal.
Replacing manifold seal & valve cover seals as I put back together. Will swap out fuel injectors before reinstall manifold easier on work bench than hunched over truck compartment.
Will suggest every avalanche owner checking these bolts for tightness as I'm sure causing lifter failures when oil pressure can't collapse lifters correctly.
Probably why so many engines needed Replacing.
Glad caught mine before caused any big failures.