2018 l5p grenade

Howdy everyone!
I have not been active here for several years, life just happens and my diesel truck herd has thinned out a little.
However...my son just bought a 2018 Chevy L5P 130K miles and the appropriate hours.

We went to pick it up, truck was very clean by salt belt standards.
Had a code for Glow plugs, was low on coolant and had very slight blow by in the oil fill.

Cleared the Glow code and it came back so we figured it was a bad plug. No big deal.

The carfax said it was in the dealership 200miles ago for a factory service memo to replace the frost plug heater.
We added 2 gallons of coolant and the light went out and coolant stayed fine.
I figured the dealership did not fill the system properly.

We drove about 250 miles and parked it for the evening.
Next morning warmed it up and started to drive. 3/4 mile it started making a loud knock from the engine.
Shut it down and got it into our shop. Still runs but has a knock, miss on 4 and 8 and smoked like crazy.
Using a borescope we saw a melted piston in 4. did not check 8 as its a pita to get to.

Anyways....we are most likely looking at a long block.

Does anyone here know of a great source for Remaned long block?
Conversely....are there any sources to avoid?
Or any other good options that make sense economically?
- We don't have a good engine machine shop locally so rebuilding isn't really an option.

Also does anyone have an idea WHY this would happen? I can see an injector sticking and burning 1 cylinder....but TWO at the same time???

Thanks everyone!

Conley Janssen

I wouldn't assume you have two dead cylinders due to 2 misfire codes. 4 follows 8 in the firing order, so unless you confirm #8 damage, it is more likely a cause of the dead #4. Before replacing the long block, you must find the current cause of failure, or risk repeating it on the next block. Your son probably bought the truck with the problem. 2 gallons of coolant (just to get the low warning reset) is a LOT of coolant, more than 25% of total capacity. It would not have left the dealer that low. A complete drain/fill is required to replace the block (frost plug) heater. Even an incomplete air purge procedure is only about 1/2 gallon, at the extreme, but not likely any shop capable of doing the heater replacement would be that far off. The coolant went away, somewhere, perhaps through a cylinder. Check the oil for coolant contamination.

Jasper builds good engines. My son just got a 6.2 gas motor for his 2011 GMC 1500
I believe Robyn has used Jasper before also/

Does your state have lemon laws ?
I would be having a very strong discussion with the dealership

DMax-
Yep, we are going to pull it before we decide anything for sure. Sent in a oil test just out of curiosity