My 2008 Sierra 1500 5.3 has had oil consumption issues since 50,000 miles. Dealers ran around problem and did bandaid fixes and I had to drive it for work, out of warranty now. 120,000 miles, slight tick the last few days and this morning I'm going to pass this old lady and felt almost a bang or pop, I was almost to work so i limped there, Engine running rough and almost feels like it could die at stop light, Check Engine Light Flashing, Stabilitrak and Traction Control lights came on too. Went into limp home mode. Checked Oil: good. Unhooked battery to reset for awhile: restarted and everything came back. So I took it to Advance auto to check codes, P0306 - #6 cylinder misfire. So I buy a spark plug/ set of spark plug wires, and ignition coil. Old spark plug covered in oil: replaced: no change. Plug wire and coil don't make any difference either. Re-check new spark plug, Oily.

Dealer confirmed no compression in Cylinder 6. Said I need a new Engine. $8000. Any opinions on this? They should have replaced engine before warranty went out, but they danced around it as I racked up miles and added oil each time I got gas...

Would it be possible to just add and AFM/DOD delete kit with a non AFM cam? My guess is #6 lifter is collapsed with possible cam damage. Would this have put enough metal shavings through the motor to ruin it?

Got my first kid coming soon and I do not have $8000 to spare but Im decent with a wrench.

Any chance GM would replace the motor?

Thanks!

 

Doubtful you will get GM to replace the motor on a 120k mile car.

Best you can do is tear it down yourself to the bare shortblock and see if there is any damage there or to the heads. Then replace whatever is necessary and go on with your life. It will be costly depending on what you find damaged or how much you can actually do yourself, but no way in heck it will come anywhere near 8k.

For less than that you can get a new forged stroker with aftermarket top end...or a brand new LS3 crate engine. Both will be much better than any re manufactured 5.3 GM will be giving you.

 

If you are comfortable doing it yourself get into that motor and assess the damage. The short block is probably toast. If you are lucky the heads are okay. You can get a remaned shortblock for drastically less than 8k.

Drop the AFM and VVT if you can. You'll loose a little low end tq and mpg but the less hassle is worth it.

 

To know what's going on you have to at least take that head off. If it was a collapsed lifter, I don't think you would have lost compression. I think the valve would have stayed closed and not opened.

Regardless, a used shortblock can be bought cheap ($500) at a salvage yard if you want to go that route. It will be a lot of work to change but certainly not $8k.