I can't complaint too much, it did make it 234,000 miles before causing a problem.
So almost a year after the Silverado transitioned from my daily to my teenage son's runabout, it started tapping...more like knocking, pretty loud (but not as much as rod knock). It also threw a code for a cylinder 4 misfire.
Some of you may know that this is the tell-tale sign for a displacement of demand lifter getting stuck in the collapsed, 4 cyl mode because cyl. 4 is one that deactivates. This can destroy the engine if run too much in this condition.
The standard shop solution is replacing lifters, a $2k job that involves pulling the heads, IF there hasn't been too much damage already. Then, it can happen again unless you delete the DoD which can cost over a grand, leaving you with a $3k solution on what is probably an old truck (mine is).
But then there's the "backyard" solution. There's a guy with a YouTube channel and a shop in South Dakota that has developed a technique to "release" the stuck lifter (special tool, $38). Then, you have to keep it from ever going into 4 cyl. mode again. So, with that tool, an intake manifold and valve cover gasket set and the electronics to turn off DoD and many hours, you too have about an 80-90% chance of fixing it. Sometimes it doesn't work, or it has gone too far for the "trick". I probably spent $200 in total, but I did some other maintenance since I had it apart.
The trick is essentially this- you have to take the intake manifold off (no small feat) then there is a plate under it called the VLOM (Valve Lifter Oil Manifold). When 4 cyl mode is called for, high pressure oil is directed though this manifold to the 4 cylinders to turn off. Oil pressure forces pins in the lifter in and the lifters collapse, turning off the cylinder. The computer also shuts the injectors off.
You take the VLOM off. Then there are passages in the block valley leading to all of the cylinders that get deactivated. I hear that the intake lifters are pretty much the only ones that fail.
You know what cylinder is your problem by taking off the valve covers and there should be a super-loose rocker. Take the rocker off on the affected valve, then in the oil passage in the valley, put a specially shaped tool, a punch of sorts, down the passage to the lifter- then tap on the punch...sometimes harder than you think is prudent and if it works, the push rod will shoot all the way out of the engine bay when it releases.
Then, you disable displacement on demand. You do this mechanically and electronically. Mechanically, the special punch comes with a bushing that you drive into a passage in the VLOM that blocks oil from being send to deactivate the lifters (the lifters are are not lubricated through the VLOM, just the cylinder deactivation). Then, you can get the computer reprogramed or, I went cheaper and got a thing that plugs into the OBD2 port and deactivates it so the signal is never sent to the VLOM and injectors are not shut off.
It's a very involved job, but she is running fine now. However, I will be selling it soon and we need a more fuel efficient car for when my son starts driving to Griffith for welding school.
Here is a video and the website for the guy where I got the tool.
https://www.crazedperformancerepair.com/
So almost a year after the Silverado transitioned from my daily to my teenage son's runabout, it started tapping...more like knocking, pretty loud (but not as much as rod knock). It also threw a code for a cylinder 4 misfire.
Some of you may know that this is the tell-tale sign for a displacement of demand lifter getting stuck in the collapsed, 4 cyl mode because cyl. 4 is one that deactivates. This can destroy the engine if run too much in this condition.
The standard shop solution is replacing lifters, a $2k job that involves pulling the heads, IF there hasn't been too much damage already. Then, it can happen again unless you delete the DoD which can cost over a grand, leaving you with a $3k solution on what is probably an old truck (mine is).
But then there's the "backyard" solution. There's a guy with a YouTube channel and a shop in South Dakota that has developed a technique to "release" the stuck lifter (special tool, $38). Then, you have to keep it from ever going into 4 cyl. mode again. So, with that tool, an intake manifold and valve cover gasket set and the electronics to turn off DoD and many hours, you too have about an 80-90% chance of fixing it. Sometimes it doesn't work, or it has gone too far for the "trick". I probably spent $200 in total, but I did some other maintenance since I had it apart.
The trick is essentially this- you have to take the intake manifold off (no small feat) then there is a plate under it called the VLOM (Valve Lifter Oil Manifold). When 4 cyl mode is called for, high pressure oil is directed though this manifold to the 4 cylinders to turn off. Oil pressure forces pins in the lifter in and the lifters collapse, turning off the cylinder. The computer also shuts the injectors off.
You take the VLOM off. Then there are passages in the block valley leading to all of the cylinders that get deactivated. I hear that the intake lifters are pretty much the only ones that fail.
You know what cylinder is your problem by taking off the valve covers and there should be a super-loose rocker. Take the rocker off on the affected valve, then in the oil passage in the valley, put a specially shaped tool, a punch of sorts, down the passage to the lifter- then tap on the punch...sometimes harder than you think is prudent and if it works, the push rod will shoot all the way out of the engine bay when it releases.
Then, you disable displacement on demand. You do this mechanically and electronically. Mechanically, the special punch comes with a bushing that you drive into a passage in the VLOM that blocks oil from being send to deactivate the lifters (the lifters are are not lubricated through the VLOM, just the cylinder deactivation). Then, you can get the computer reprogramed or, I went cheaper and got a thing that plugs into the OBD2 port and deactivates it so the signal is never sent to the VLOM and injectors are not shut off.
It's a very involved job, but she is running fine now. However, I will be selling it soon and we need a more fuel efficient car for when my son starts driving to Griffith for welding school.
Here is a video and the website for the guy where I got the tool.
https://www.crazedperformancerepair.com/
Last edited:
