Chevy Colorado Diesel Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Hello everyone,
I'm considering purchasing a 2017 CCLB 4x4 with a little over 160K on the clock. It's a one-owner vehicle that has been well-maintained and was traded in for a full-size Duramax.
The first and only owner reportedly performed all maintenance himself, so there is little record of maintenance being done. But judging by the way it runs and drives (perfect) he kept up with it.
I've been researching the most common major failures of high(ish) mile LWN engines and it seems that occasionally an injector tip will crack, they will spray the same spot on a piston, and in time the piston will develop a hole. Other than that, I haven't read about a lot of issues in high-mile engines.
My thought would to be preemptively replace the injectors with Exergy stock size injectors to prevent this from happening. Then probably a full delete and mild tune for MPG. I live at high elevation and while I never flog my vehicles, long and steep pulls are common.
With the other diesel engines I've owned (Ford 7.3, 6.4 and Chevy LYY) I managed 300K+ on all, and I purchased each above 200K. But the LWN scares me just a bit.
Are there any other red flags or issues you guys know of that I should investigate? I know there aren't many with this high miles and it seems I would be jumping right into the deep end......

Thanks for any thoughts. I'll post back up if I buy her this weekend!

Cheers!
 

·
Registered
Joined
·
245 Posts
If you replace the injectors just go with GM/ACDelco replacements from Rock Auto or wherever is cheapest. I contacted Exergy about their stock/+0% injectors and what modifications/upgrades/improvements they do to them as someone else made the claim/assumption that Exergy is doing something to make them more durable and Exergy flat out said they do nothing, they are 100% factory stock, untouched injectors. I don't know why they're charging so much for them, it's quite a bit more than Rock Auto.
 

·
Registered
Joined
·
661 Posts
Hello everyone,
I'm considering purchasing a 2017 CCLB 4x4 with a little over 160K on the clock. It's a one-owner vehicle that has been well-maintained and was traded in for a full-size Duramax.
The first and only owner reportedly performed all maintenance himself, so there is little record of maintenance being done. But judging by the way it runs and drives (perfect) he kept up with it.
I've been researching the most common major failures of high(ish) mile LWN engines and it seems that occasionally an injector tip will crack, they will spray the same spot on a piston, and in time the piston will develop a hole. Other than that, I haven't read about a lot of issues in high-mile engines.
My thought would to be preemptively replace the injectors with Exergy stock size injectors to prevent this from happening. Then probably a full delete and mild tune for MPG. I live at high elevation and while I never flog my vehicles, long and steep pulls are common.
With the other diesel engines I've owned (Ford 7.3, 6.4 and Chevy LYY) I managed 300K+ on all, and I purchased each above 200K. But the LWN scares me just a bit.
Are there any other red flags or issues you guys know of that I should investigate? I know there aren't many with this high miles and it seems I would be jumping right into the deep end......

Thanks for any thoughts. I'll post back up if I buy her this weekend!

Cheers!
The one thing you should know is getting the #4 injector out is a PITA. It sits in a spot that requires the cowl to be removed and GM uses an industrial strength adhesive in that area. Second to that process would be lifting the cab 3" to 5" to get that last injector out.
 

·
Registered
2017 colorado z71 modified
Joined
·
78 Posts
Awful weird/suspicious how all of a sudden diesels are burning holes in pistons, used to be you had to run propane on your diesel to achieve that or nitrous on a gas engine.
If this continues to be a problem maybe it is time for a little water/methanol injection to cool things down.
 

·
Registered
Joined
·
245 Posts
Awful weird/suspicious how all of a sudden diesels are burning holes in pistons, used to be you had to run propane on your diesel to achieve that or nitrous on a gas engine.
If this continues to be a problem maybe it is time for a little water/methanol injection to cool things down.
The assumption is the injector tip cracks which results in what is like a plasma beam of diesel fuel hitting the piston which eventually creates a hole. It's not something that happens as a result of normal operation.
 

·
Registered
2017 colorado z71 modified
Joined
·
78 Posts
Wouldn't something need to hit or overheat said injector to Crack it and why is it only one piston? Normally on a diesel you get multiple burned pistons.
Is injector timing off? If heat is cracking it then there is an oiling issue. Sucked in a compressor blade? Dpf filter clogged? Egr clogged? Something not put together correctly when engine was built?

I feel like there is more to the story than what is being said about these injectors online. Having 200k on a 2016/2017 supposedly the ones to stay away from and doing all the truck stuff offroading, towing etc heck I even lock up the g80 and do burnouts when it's time for new tires.
Other than regular maintenance I beat my truck like a 90s Ford ranger.
 

·
Registered
Joined
·
245 Posts
Wouldn't something need to hit or overheat said injector to Crack it and why is it only one piston? Normally on a diesel you get multiple burned pistons.
Is injector timing off? If heat is cracking it then there is an oiling issue. Sucked in a compressor blade? Dpf filter clogged? Egr clogged? Something not put together correctly when engine was built?

I feel like there is more to the story than what is being said about these injectors online. Having 200k on a 2016/2017 supposedly the ones to stay away from and doing all the truck stuff offroading, towing etc heck I even lock up the g80 and do burnouts when it's time for new tires.
Other than regular maintenance I beat my truck like a 90s Ford ranger.
Debris or excessive wear can cause the tip to crack, there's no reason to expect multiple injector tips to fail at the same time so one injector failing and causing one damaged piston is pretty typical.

That said, the pictures I've seen of holes in pistons with the LWN definitely do NOT look like melted pistons from a repeated jet of fire hitting it, the pistons are cracked and bits of the piston break off leaving a hole. Holes melted through pistons literally look like the piston was molten around the hole.

The other assumption I've been told is that the injectors are partially stuck open which leads to this, however I haven't seen any evidence of that either. An injector that is stuck open so it's constantly spraying fuel results in a loud engine knock from the affected cylinder.

I do feel like there may be some potential issue with the 2016-2019 injectors, though, as GM has updated the injectors for late-2019 or 2020+ models and they aren't backwards compatible with the previous injectors. Different connectors and likely different programming in the ECM. I just feel like there are more assumptions than facts which just muddy the waters and we really don't truly know what is causing the cracked pistons that sometimes have holes due to the fracturing.
 

·
Registered
Joined
·
27 Posts
The one thing you need to be aware of is they have a timing belt that needs to be changed every 160000km. And they are also known for having rear main seal oil leaks. Mine started leaking and I had to have it done under warrenty gm uses a cheap Teflon seal instead of rubber it's stupid.
 

·
Registered
Joined
·
245 Posts
The one thing you need to be aware of is they have a timing belt that needs to be changed every 160000km. And they are also known for having rear main seal oil leaks. Mine started leaking and I had to have it done under warrenty gm uses a cheap Teflon seal instead of rubber it's stupid.
The timing belt interval is 150k miles or 240,000km.
 
1 - 10 of 10 Posts
Top