Burning oil at start up

[George Owens]

On start up most of the time after letting the car sit for a while I get a puff of blue smoke and then after that it’s fine. It got to the point that I had to change the number six spark plug because it was covered in oil no other spark plug had been replaced, I’ve been reading it could be valve seals but I also saw another post that said it could be the passenger side valve cover I’m just trying to get pointed in the right direction before I order some parts. 08 Tahoe 5.3 175k with AFM but use range disabler

 

[tom3]

I'd vote on the valve seals for that cylinder.

 

[intheburbs]

Blue smoke means oil is getting into a combustion chamber. Valve cover doesn't cause that.

I agree with tom3 on the valve seals. I'd pull spark plugs to look for oil fouling, to identify the problem cylinder.

 

[wjburken]

X3 for valve seals.

 

[89Suburban]

Add a catch can and bump the heat range up one on the plug.

 

[Geotrash]

+1 more on the valve stem seals. And they're easy to replace in-vehicle with the heads on.

While you're in there, replace the driver's side valve cover to make sure you have the updated design. The Dorman part is fine for this. And as @89Suburban says, optionally install an oil catch can.

There are 2 separate oil control issues. One is caused by a poor baffle design for the PCV system on the original valve cover that leads to the engine ingesting more oil and causing sticking piston rings over time. The updated valve cover design fixes most of this, and the optional oil catch can will capture any oil that still gets by even with the updated baffle design. The second is that the valve stem seals harden over time and allow oil to seep down into the cylinders after shutdown. Your symptoms are caused by this second one, but it would be wise to address both at the same time.

 

[George Owens]

+1 more on the valve stem seals. And they're easy to replace in-vehicle with the heads on.

While you're in there, replace the driver's side valve cover to make sure you have the updated design. The Dorman part is fine for this. And as @89Suburban says, optionally install an oil catch can.

There are 2 separate oil control issues. One is caused by a poor baffle design for the PCV system on the original valve cover that leads to the engine ingesting more oil and causing sticking piston rings over time. The updated valve cover design fixes most of this, and the optional oil catch can will capture any oil that still gets by even with the updated baffle design. The second is that the valve stem seals harden over time and allow oil to seep down into the cylinders after shutdown. Your symptoms are caused by this second one, but it would be wise to address both at the same time.

I did see how to replace them While still attached to the engine but that requires me to have compressed air which I don’t have, was considering taking the heads off to replace them and while I’m there replace the lifters as a preventative maintenance

 

[89Suburban]

I did see how to replace them While still attached to the engine but that requires me to have compressed air which I don’t have, was considering taking the heads off to replace them and while I’m there replace the lifters as a preventative maintenance

Shove some nylon rope into the cylinder at BDC of the beginning of the compression stroke then slowly turn towards TDC to press and hold the valves closed. Not all the way of course. Use common sense. This way you can do the problem cylinder only and see it if fixes the problem.

 

[Doubeleive]

I did see how to replace them While still attached to the engine but that requires me to have compressed air which I don’t have, was considering taking the heads off to replace them and while I’m there replace the lifters as a preventative maintenance

harbor freight has air compressors for cheap, flea market, craigslist, offer up, facebook, borrow from a friend, or if you only need it for this buy one and then take it back.

 

[Geotrash]

Shove some nylon rope into the cylinder at BDC of the beginning of the compression stroke then slowly turn towards TDC to press and hold the valves closed. Not all the way of course. Use common sense. This way you can do the problem cylinder only and see it if fixes the problem.

This ^^^ It's called the rope trick. Works great. Or, you can do each cylinder one at a time. Rotate the crank until you're close to TDC on each cylinder as you go, verify it with a wooden dowel. The valves won't fall into the combustion chamber if the piston is close to TDC. Pulling the heads to do the lifters is great, but at that point you're most of the way to a cam swap. It's a snowball effect...