Hey guys I’m new to the forum but I’ve been a long time subscriber since I bought my 14 Sierra new in feb 2014. So I’ve read lots of horror stories on the site and I thought I’d tell you guys about my experience.
A few weeks ago over 5r holidays, my girlfriend and I were returning a uhaul after moving and she was following in my truck, she called to say that the check engine light was on and the truck had reduced power. We dropped off the uhaul and I hopped in and could tell it was misfiring and had a rough idle. I took it to my local mechanic and he told me cylinder 4 was misfiring and he tried a coil pack but that didn’t fix it, he did a compression test and it was holding compression but he told me this was gonna be a bigger problem.
luckily I still had powertrain warranty so I contacted the dealership that I bought the truck from and they had me tow it there using gm roadside. So my first hats off to gm, the lady I had on the phone from roadside assistance asked her manager to waive the tow fee as I was having it towed to my home dealership that was > than the 50 miles that they cover for free.
Once the truck made it to the dealership, it only took the. A couple of hours to figure out I had a failed lifter and broken rod for cylinder #4. Now I was freaking out because I’ve read horror stories on this site about having to argue with regional managers for warranty work this significant and I’ve heard dealerships arbitrarily saying work isn’t covered under warranty for whatever reason. Thankfully I can say my service advisor set me up with a rental the same day and reassured me that everything would be covered by gm. He did say parts were on backorder and it would take approx 2 weeks. Almost 2 weeks to the day, truck was ready to be picked up with 0 hassle the entire time.
This is my 3rd truck with the 5.3 and the only time I’ve had a significant mechanical issue. The truck only had 85000 km (around 50k miles) sure I was PO’d that my truck was out of commission for 2 weeks but I was extremely thankful that gm stood behind their product and was able to fix the truck for me. The truck seems to run fine now but I don’t know if I will keep it as I don’t know if it will be the same or if the issue will reoccur. I do know that my next truck will definite be another Chevy or Sierra. I can’t wait to see the reveal of the new Chevy this weekend at Detroit!
Jut thought I would post a positive warranty repair story and throw a kudos out to gm for making things right with me
A few months ago I bought a 2007 GMC Sierra (new body) with 150,000 miles on the clock. It has the LH6 in it. It has since gotten cold outside and when I start it in the mornings It has what I am sure is a rod knock. It goes away after the engine warms up. It has good oil pressure. I have always been a ford guy and wasn't too familiar with these engines otherwise I would have avoided these early AFM engines like the plague. It sounds a lot "deeper" than a lifter click. I have removed the valve covers and confirmed that I don't have a collapsed lifter or flattened cam. The thing consumed over a quart of oil in the last 2,000 miles. I had a cylinder 1 misfire and when I pulled the plug it was pitted and the porcelain was cracked showing tons of detonation. I replaced the plug and that fixed the misfire. All the other plugs look great.
Onto my question. With all these issues an the reputation of these AFM lifters and oil consumption I kinda want to get ahead of it and plan on putting an engine in it. This is my daily driver so i need to minimize down time. I was looking to get a block and get it ready to go in the truck (as money permits) so there is no huge rush or surprises. The problem is these specific LH6 Aluminum blocks were only used from 2005-2009 and are not the easiest/cheapest to find. The LY5 however is the iron counterpart to it and cheap and easy to find since they produced them 2007-2014 and were more common. I don't care about the 100lbs. Does everything bolt up? And would the computer freak out? I plan on eliminating the AFM and putting some trustworthy lifters and a cam in it so I will need some computer work done anyways hopefully it can be programmed enough to handle a different block? Would someone with HP Tuners be able to do the computer work or does the whole thing need to be sent off/replaced?. I've rebuilt a few engines It's just this computer stuff that gets kinda hayzey. If I am deleting the AMF is there another Gen IV block that would work for this application? Screw it and get a 6.0 and stroke it?
I have a 2016 Crew Cab Silverado 4x4 that I bought new last summer. I have noticed that recently when the active fuel management switches from 4 to 8 cylinders that there is a loud (loud enough to hear it with the windows up, A/C and radio on) squeak like noise that comes from the truck. It makes this noise every time it switches from 4 to 8, no matter what the speed.
I don't remember it doing this until recently. I've googled active fuel management noise, active fuel management squeak and tons on other combinations, but haven't gotten any results.
I wanted to check on here and see what you guys thought before looking like a dumb ass and taking it back to the dealership.
I have a 2007 Tahoe 5.3L LMG (AFM) 4x4 LTZ. Truck has 190k on it. The other day it developed a very rough idle and flashing CEL. Prior to this there was no indication of a problem. Scanner says misfire cylinder 1. I do all of my testing that I can do such as spark plugs, wires, verify injector signal with noid light etc. End up using compression tester to find 0 PSI on #1 and other cylinders at 110-120 PSI. During one of the compression test on #1 the gauge jumped to 60 PSI then next cycle dropped to 0 (unsure how to interpret that). Took truck to local shop and despite my efforts to inform them of the AFM lifter issues that could be causing this loss of compression they basically said that based on the 190k mileage i should only consider replacing with long block rather than repair the heads. They then quote $6600 for Jasper reman and install.
So to my question... Are they right the I should do a reman long block or consider repairing heads? I know I have been lucky to get that kind of mileage without issue but just wondering what others would do. Truck is in great condition otherwise and I plan to keep for the foreseeable future. Thanks for your help.
I have a 2010 Chevrolet Tahoe PPV with a 5.3L LMG and a 6L80 Trans (MYC) looking to drop in a 6.2L L9H. As far as I understand it is a direct swap. Would I run in to any issues or codes as far as the L9H not having AFM/DOD? I plan on using the 5.3L PCM and having it re flashed to work with the 6.2
Or do I look for a L94 that has FlexFuel, VVT, AFM like the LMG does?
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