2010 DENALI 6.2 Motor "Seized"

[dyce51]

Quick update! Got the pan pulled last night and pulled piston out. Cylinder wall has no damage so ordered up the correct OEM replacement piston, got a head lined up (will be gone through and surfaced) along with the gaskets and hardware I'll need ordered. I did order a new rod bearing since it's cheap, not sure yet if I will replace the old one or not. It looked good, but if I'm in there and knowing that there was contact between piston and head via a seat...might be good insurance.

I did verify the motor has the later style valve cover, along with the shield on the AFM Relief in the pan. I ordered up a catch can to add while I'm at it.

As I get it put back together, I will keep the updates coming!

 

[dyce51]

Been almost a MONTH! Back for an UPDATE!!! Slowly over the last few weeks got my parts in hand and motor back together. Went back together fairly well, for being in the vehicle. Not ideal, but it worked. Busted the crappy heater hose quick connects at the firewall so replacing those today. Also chasing p0206:00 injector code...swapped 2 around to see if it follows or not and will dig into it more once the heater hoses are back on.

Will see long term how she holds up. Have a trip early June I would love to take it on, so want to get some good miles on it here the next month to work out any bugs.

 

[dyce51]

Heater hose connections are all fixed up and my injector code/misfire sorted out! At this point, I'm calling it case closed! Added up receipts and I got it done for right around $1200...considering I bought this with plans to swap the motor thinking it was toast...I'm pretty happy!

Going to drive it and hopefully work out any other issues that come up. Going through the history, brakes have been done less than 20k miles ago, trans was replaced around 50k miles ago...so may be due for a flush before to long, front end was gone through in the last 50k miles...so quite a bit of major work was done that I would normally be looking at doing.

One thing I didn't see in the maintenance history was differential fluid changes...so I may do that before our trip in June.

One thing I am curious on...in our other rig (2013 with a 5.3)...we run E30 quite often vs E85 as mileage seems to be much better and it's a decent price, anyone had any experience running the E30 in these rigs..."Supposedly" the octane rating is supposed to be between 92 & 94...depending on ethanol content...

 

[Just Fishing]

I picked up a 2009 Denali In similar condition scenario. Pulled oil plug and coolant came out with the oil. Couldn’t turn motor over with breaker bar on crankshaft pulley. Had to pull engine with transmission together. Pulled the heads and here is what I found, looks like the piston exploded. Taking block to machine shop to assess, but think it can be rebuilt. **Update-looks like a valve seat came loose and caused the piston to implode.***

This is why you run premium and not regular in a 6.2.