2007 GMC Sierra gave up the ghost

[GeorgeG.]

Assuming it has good oil pressure, the oil looks okay and it's not misfiring that could be a carbon knock. I'd try some seafoam and see what happens.

I'd also run it without the belts to make absolutely sure it's not an a/c compressor, tensioner or something else stupid.

Crap, I forgot about this. I'll try it this weekend. I literally have not touched it in several weeks. I did run some Marvel in the oil and let it idle for about 5-10 minutes and then changed the oil. It was a stretch but I read a suggestion that the lifters might possibly have crud in them.

Likely just lifters. Check the filter for bearing material and if it looks good pull the cam to inspect for damage.

I saved the oil filter. I'll check it tomorrow.

[GeorgeG.]

I cut the filter open tonight. I don't see any brass or metal on the outside of the filter, although it's black and kind of hard to tell. I can feel some grit but when I wipe it in my hands, it's black does not resemble metal flakes or shavings.

I also took a rubber hose and listened around the engine. I still can't really pin point it. I was able to put the hose against both sides of the block, below the exhaust manifold and was not able to locate the noise. I also fed it through different parts near the intake/heads and still nothing. Then I placed it on the passenger exhaust manifold and the noise was definitely there, the driver side exhaust manifold and it was very faint. Would the sound travel to the exhaust if it was a rod bearing?

Also, I discovered that if it hold the brake pedal and give it a little gas, there's a second knock that is audible right after the first tap sound. Can someone host a video for me? I was beginning to be optimistic about it just being a cam and lifter job but this second knock has me wondering about piston slap.

If I can ever get this Lightning out of my driveway, I'll start tearing into it.

[GeorgeG.]

Anything automotive in Denton. John and Jason know those ls motors well and James can handle the tune.

One stop shop and members here

What's their screen names here?

[DON SVO]

What's their screen names here?

DvilleGT is James.
JOHN is John Dodson. He hasn't been on in a while. He's on Facebook though.

[GeorgeG.]

Damn, I had no idea that this happened in March. Since my other truck was stolen last Friday, this kind of forces me to deal with this truck. The 6.0 is not really an option anymore as this will most like be handed over to my now 14 yr old daughter for when she drives. So, looks like I'm just going to keep it stock, including keeping the AFM setup.

The engine has 197k miles so if my daughter is going to be driving it, I don't need any issues out of it.

Option A - I plan on tearing into the top, taking the head off that has the knock. If that confirms, then I'll most likely remove both heads to replace the AFM lifters along with the cam. Then I'll probably remove the rest of the engine because the oil pan is leaking pretty bad (low oil light comes on just past 5k miles from an oil change) and I've read online that doing that while in the truck is a PITA. Also, since I don't want any issues, I may look into sending it off for a refresh since it has damn near 200k miles. I'll need a shop suggestion too. I won't be using the one in Sherman that left metal shavings on my Lightning heads.

Question...would you refresh it at 200k if you planned on keeping it? If I'm that far into it, might as well at a minimum replace bearings, right? Can you just hone the cylinders and install new rings or do you need to bore it out? (I don't intend to do this).

Option B - buy a reman engine, save the headache and just worry about swapping the accessories. Who are the reputable engine builders?

I'm fairly certain the cost will be about the same so only thing I'd be saving is time and I only have 30 days of rental coverage anyway.

Thoughts?

[GeorgeG.]

Well a crate engine from the GM dealer is $5,800 plus a couple hundred in gaskets and such. An engine rebuilder might be less than that but I'm sure I won't spend this much rebuilding this one.