NEVER Buy These 11 Chevrolet Engines (And 5 That’ll Run Forever)

Added: 2026-05-10

[00:00:00]Your next Chevrolet could be the most reliable vehicle you've ever owned, or it could be a money pit that destroys your savings one repair bill at a time.

[00:00:08]The difference isn't the trim level, the color, or even the mileage on the odometer. It's what's sitting under the hood. After 15 years working on these trucks and cars, I've watched certain engines fail the same way, on the same vehicles, at the same mileage, over and over again. And nobody is warning buyers before they sign the paperwork. Hi, my name is Kyle, and this is Chevrolet Garage. If you're new here, this channel is dedicated to one thing: giving you the real information about your Chevrolet that dealerships, service writers, and frankly even Chevrolet itself would rather you never find out.

[00:00:46]Engine number 11, the 3.6 LY7, the oil burner.

[00:00:52]An engine that looked absolutely spectacular on paper, and turned into an absolute nightmare in real life. The 3.6 LY7 debuted in 2004, and found its way into everything from the Chevrolet Malibu to the Impala to the Equinox.

[00:01:09]Smooth, refined, genuinely powerful for its displacement. On a test drive, this engine feels like Chevrolet finally figured it out. They hadn't. The LY7 has a well-documented oil consumption problem that borders on legendary.

[00:01:25]Owners report burning a quart of oil every thousand miles, not leaking, burning. The engine is just silently consuming oil during normal operation, and the symptoms don't show up until the damage is already done. By the time your low oil light illuminates, you may have already spun a bearing or scored a cylinder wall. The root cause is piston ring design. The rings simply don't seal the way they should, allowing oil to migrate into the combustion chamber, where it burns off cleanly enough that you don't even see blue smoke most of the time. Chevrolet issued technical service bulletins on this issue, but never issued a proper recall. Dealers were instructed to call the consumption normal if it fell within a certain threshold. 1 qt per 1,000 mi was, "acceptable."

[00:02:11]You tell me if that sounds acceptable when you're writing a check for a replacement engine at 80,000 mi. If you're looking at a used vehicle with an LY7 under the hood, walk away.

[00:02:22]If you absolutely must buy one, check the oil every single fill-up. Not every oil change, every fill-up. Engine number 10, the 2.4 Ecotec LAF, the timing chain killer.

[00:02:36]The 2.4 LAF Ecotec sounds like a sensible, fuel-efficient choice. And for the first 60,000 mi, it usually is.

[00:02:45]Then the timing chain stretches, the tensioners fail, and everything goes sideways very quickly. This engine showed up in the Chevrolet Malibu and the HHR from around 2008 through 2012.

[00:02:58]The timing chain system on this engine is genuinely poorly designed. The plastic guides wear faster than they should, the tensioners lose pressure, and when that chain starts slapping around inside your engine, you will hear it every cold start as a rattling sound that owners describe as someone shaking a coffee can full of rocks. Here's what makes it worse. That rattle on cold start isn't just annoying. Every time that chain slaps, it's eating the plastic timing guides alive. By the time most owners take it to a shop, the guides are destroyed and debris has circulated through the oil system. A timing chain job on this engine runs $1,200 to $2,000.

[00:03:38]And because this failure is so predictable and so common, there is absolutely no reason Chevrolet couldn't have addressed the tensioner design long before these vehicles were sold.

[00:03:49]They chose not to. If you're shopping used Malibu's or HHRs from this era, start the engine cold and listen. That rattle tells you everything you need to know. Engine number nine, the 5.3 LC9 AFM, the lifter lottery. Oh boy, where do I even start with this one? The 5.3 LC9 with active fuel management is probably responsible for more repair bills, more heated arguments at dealership service counters, and more gray hairs on owners' heads than any other Chevrolet engine of the modern era. And the frustrating part is that without AFM, the underlying 5.3 is actually a pretty solid engine. But Chevrolet bolted on this fuel-saving cylinders deactivation system and turned a dependable truck engine into a ticking time bomb. Here's what active fuel management does. Under light load driving conditions, the system deactivates four of the eight cylinders to save fuel. In theory, brilliant.

[00:04:49]In practice, the special AFM lifters that collapse to allow this deactivation are fragile.

[00:04:56]They fail. When they fail, they send metal debris through your entire oiling system. That debris reaches your camshaft, then your bearings. By the time you hear the lifter tick, you're often looking at a full engine replacement, not just a lifter swap, because the metal contamination has traveled everywhere. The repair bill for a proper AFM lifter failure repair, done right, including camshaft replacement and full flush, runs $4,000 to a truck that might be worth $12,000.

[00:05:27]I've seen this happen at 60,000 mi. I've seen it happen at 45,000 mi. The mileage almost doesn't matter, because this is a design failure, not a wear failure. The fix, if you already own one of these, is to install an AFM disabler device immediately.

[00:05:43]They run about $50 and plug into your OBD-II port. They electronically disable the cylinder deactivation system and your engine runs as a normal eight cylinder from that point on. Do it today, not next month, today.

[00:05:58]This engine appeared in trucks from 2007 through roughly 2014.

[00:06:03]If you're buying a used Silverado or Suburban from this era, the very first question you ask is whether the AFM has been disabled. If the seller doesn't know what that means, assume it hasn't been done and factor the risk into your offer.

[00:06:19]Engine number eight, the 3.5 L Z4, the head gasket special.

[00:06:26]The 3.5 L Z4 V6 showed up in the Impala, the Monte Carlo, and the Colorado between 2004 and 2008. It's got a smooth power delivery and decent performance numbers for a naturally aspirated V6 of that era.

[00:06:44]It's also got head gaskets that fail with the kind of depressing reliability that would be impressive if it wasn't so expensive. Coolant intrusion into the combustion chamber, external coolant leaks, overheating that occurs without obvious warning because the failure is often slow. By the time the temperature gauge climbs, the head has already warped slightly and you're looking at a head gasket replacement job of 1200 to 2000 dollars minimum.

[00:07:11]And here's what mechanics know that owners don't. The head gasket on the LZ4 isn't just a material failure, it's a design clearance issue combined with a cooling system that runs hotter than it should under sustained load. The two problems amplify each other. You can replace the head gasket perfectly and be back in the shop 18 months later for the same repair if the cooling system isn't also completely serviced and the root temperature issue addressed. Avoid it.

[00:07:41]Engine number seven, the 6.0 LY6 truck engine, the carbon choker. Now, I want to be very careful here because the 6.0 LY6 has a devoted following and honestly, I understand why. It's a big, torquey, capable engine that tows like a champ and sounds absolutely menacing when you get into it. But, the LY6 has a carbon build-up problem on the intake valves that is severe enough that I'm putting it on this list. This engine uses direct injection combined with the AFM cylinders deactivation system we already talked about.

[00:08:18]That combination creates an environment where intake valve carbon build-up accumulates faster than almost any other Chevrolet engine I've worked on.

[00:08:27]At 60,000 mi, the intake valves on neglected examples look like the inside of a chimney.

[00:08:33]The result is rough idle, reduced power, misfires, and fuel economy that drops off a cliff. A walnut blasting service to clean those valves runs $500 to $900.

[00:08:44]Add a potential AFM lifter failure on top of that and you're carrying significant financial risk. If you own one and love it, catch can installation and frequent Italian tune-ups keep it manageable. But, as a used purchase without documented maintenance history, it's a gamble.

[00:09:02]Engine number six, the 2.0 LNF turbo, the boost destroyer.

[00:09:10]The 2.0 LNF turbocharged four-cylinder was Chevrolet's attempt to prove that a small displacement engine could deliver serious performance. And in the Cobalt SS and the HHR SS, it genuinely delivered lots of fun on a twisty road.

[00:09:26]The problem is that fun comes at a cost that shows up reliably around 70,000 to The turbocharger on the LNF runs extremely hot and the oil feed system to the turbo bearings is marginal. Skip even one oil change on this engine, and you're accelerating turbo wear dramatically.

[00:09:46]The bearings develop play in the shaft, the turbo starts smoking, and a replacement turbocharger for this specific application runs $800 to $1,500 installed. The high-pressure fuel pump also has a documented failure rate that results in hard starting, rough running, and sometimes a complete no start condition.

[00:10:07]Replacement runs $400 to $600. This engine rewards meticulous maintenance with genuinely fun performance. It punishes neglect almost immediately. In a used vehicle where you can't verify the service history, the risk is simply not worth it. Engine number five, the 3.9 L LZ8, the forgotten failure.

[00:10:27]Nobody talks about the 3.9 LZ8, and that's honestly part of the problem.

[00:10:33]This V6 appeared in the Impala and Monte Carlo from 2006 through 2008 as an upgrade option over the base V6. The sales pitch was compelling. More displacement, more power, more fun. What buyers got was the same head gasket vulnerabilities as the smaller V6s of this era, combined with a valve train that develops a persistent tick at higher mileage that is, and I'm being honest here, almost impossible to fully eliminate without a complete engine rebuild. I've seen shops throw three sets of lifters at these engines chasing a tick that just comes back six months later. It's not a catastrophic engine.

[00:11:10]It won't necessarily strand you, but it will nickel and dime you from about 80,000 mi onward in a way that gets very old, very fast. Engine number four, the 4.2 L L8 inline six, the timing nightmare. The 4.2 LL8 inline six in the Trailblazer and Envoy is one of those engines where you read the spec sheet and think Chevrolet has a genuine winner. Smooth, strong, and an inline six configuration that is almost universally regarded as one of the most naturally balanced engine layouts in existence.

[00:11:45]And yet, the timing chain system on the LL8 is a multi-stage, multi-chain setup that uses a transfer case style arrangement to drive everything from one end of this long engine to the other.

[00:11:58]When it works, it's an engineering marvel. When it starts to wear, and it will, you're dealing with a job that involves removing what feels like half the front of the engine. Labor charges alone on a full timing chain replacement for this engine regularly run $2,000 to $3,000 before parts.

[00:12:16]And the wear isn't subtle. The chain stretch, the guides crack, and you get a rattle on startup that owners often ignore for far too long because they don't realize how serious it is. Ignore it long enough, and the chain jumps a tooth. At that point, you're potentially looking at bent valves and a much larger conversation about whether the vehicle is worth repairing at all. For a used Trailblazer, the timing chain condition is the first and most important question.

[00:12:44]Budget for the repair when buying, and you might get a good deal. Ignore it, and you'll regret it. Engine number three, the 5.3 L33 aluminum block, the cooling crisis. The L33 was Chevrolet's aluminum block version of the 5.3, offered in certain high output pickup truck applications in the early 2000s.

[00:13:06]Lighter weight, solid power output, genuinely impressive on paper. The aluminum block runs hotter than its iron block counterpart, and is significantly less forgiving of cooling system neglect. A marginal water pump, a slightly low coolant level, a thermostat that's sticking even just a little bit.

[00:13:25]On the iron block 5.3, these are manageable. On the L33, they become expensive problems fast. Aluminum warps.

[00:13:34]And when the block warps even slightly on this engine, you're dealing with oil leaks, coolant intrusion, and ultimately a repair bill that can exceed the vehicle's value. The L33 was also less common than the standard iron block 5.3, which means fewer mechanics have experience with its specific quirks, and part sourcing can occasionally be frustrating. If you see one at a used car lot, have it fully inspected, including a cooling system pressure test, before you even consider a purchase. Engine number two, the 3.6 LFX.

[00:14:07]The oil starvation special.

[00:14:10]This one physically pains me to put on this list, because the LFX is in so many vehicles I genuinely like. The Camaro, the Malibu, the Traverse. It replaced the troubled LY7, and in many ways it's a better engine. Smoother, more refined, more powerful. But it has a catastrophic oil pressure failure mode that has destroyed thousands of these engines, and continues to destroy them today. The issue is a combination of the oil pickup tube design and oil pan baffling that under certain hard cornering or aggressive braking conditions allows the oil pickup to momentarily lose prime.

[00:14:46]Oil pressure drops. Sometimes briefly, sometimes catastrophically. And here's what makes this worse than a typical oiling issue.

[00:14:55]The LFX does not always throw a check engine light or low oil pressure warning in time to prevent damage. The engine can drop pressure, damage bearings, and recover enough to keep running. But now it's running with scored bearing surfaces that will eventually fail completely. Owners report sudden engine failure with no warning at all. A full engine replacement on an LFX equipped Camaro or Traverse runs $5,000 to $9,000.

[00:15:23]This is not a cheap problem. If you own one, the modifications that help include an improved aftermarket oil pickup tube and regular oil changes on a strictly 5,000 mi interval using full synthetic oil. Never, ever let the oil level drop below the full mark on this engine.

[00:15:40]Engine number one, the 2.9 LLV, the wrong engine in the wrong truck. And the number one engine to avoid is the 2.9 LLV inline four-cylinder that appeared in the Colorado and Canyon from 2004 through 2012.

[00:15:58]This engine doesn't have one dramatic fatal flaw. It has a relentless collection of medium-size problems that, taken together, make it one of the most frustrating ownership experiences in the modern Chevrolet lineup.

[00:16:11]Timing chain issues, oil consumption, a power output that is genuinely insufficient for a mid-size truck, fuel economy that doesn't even justify the sacrifice in performance. I've had owners tell me this engine feels like it's working at 100% capacity just to maintain highway speed with two people and a light load in the bed. Chevrolet put this engine in a truck body and called it a day. The Colorado deserved better and the buyers who chose it definitely deserve better. Avoid it completely. If you want a four-cylinder Colorado, the later 2.5 and 2.8 diesel options that came later are in a completely different universe. Now, the good news.

[00:16:55]Five engines that'll run forever. All right, enough bad news. Let's talk about the engines that will make you fall in love with Chevrolet all over again.

[00:17:04]Number five, the 3.8 L36.

[00:17:08]I know what you're thinking. Kyle, the L36 is old and you're right. This pushrod V6 appeared in full production through the 1990s and early 2000s in the Impala, Monte Carlo, and Camaro. And it is, without question, one of the most bulletproof engines Chevrolet has ever bolted into a passenger car. Simple design, proven technology, an oiling system that just works. These engines routinely hit 200,000 mi with basic maintenance and keep going. The L36 doesn't need to be babied. Change the oil, change the coolant, replace the spark plugs, and this engine will out last the body it sits in. I've seen L36-powered Impalas with 250,000 mi that start on the first crank every single morning. Number four, the 4.8L R. Four.

[00:17:59]The 4.8L R4 is the unsung hero of the LS engine family. It showed up in trucks and SUVs from 1999 through 2013, and it is, pound for pound, one of the most reliable truck engines ever produced in America.

[00:18:15]It doesn't have AFM. It doesn't have variable valve timing. It doesn't have any of the technology that makes other engines expensive to repair. It's a simple iron block pushrod V8 that makes adequate power and simply refuses to die. Owners regularly report 300,000 mi on original engines with nothing more than oil changes and basic maintenance.

[00:18:37]Mechanics love working on them because they're simple. Parts are cheap, and the design has been proven over decades of real-world use.

[00:18:46]If you're buying a used Silverado or Tahoe and you see a 4.8 under the hood, consider it a very good sign. Number three, the 5.3L 96. The L96 is the 5.3 you want. This is the iron block non-AFM version of the 5.3 that appeared in commercial and fleet applications. Without the active fuel management system dragging it down, this engine is extraordinarily reliable.

[00:19:12]The iron block handles heat better than aluminum. The oiling system is robust.

[00:19:17]And the fundamental LS architecture it's built on is one of the most over-engineered pushrod designs in automotive history. If you can find a used vehicle with an L96, you found something worth paying attention to.

[00:19:30]These engines are rare in civilian applications, but they show up in certain Silverado HD configurations and fleet disposal sales. The absence of AFM makes this engine dramatically more dependable than its LC9 counterpart.

[00:19:46]Number two, the 6.6 Duramax L LBZ.

[00:19:52]I'd be lying if I said I wasn't a little bit excited to talk about this one. The 6.6 LBZ Duramax diesel, produced from 2006 through 2007, is widely regarded as one of the greatest diesel truck engines ever built, not just by Chevrolet. Ever built, period. The LBZ came before the emissions equipment that complicated later Duramax engines significantly. No diesel particulate filter, no selective catalytic reduction. Just a clean, powerful, mechanically beautiful diesel that makes enormous torque, tows effortlessly, and with them proper maintenance will run for 400,000 mi without significant internal work. Yes, 2006 and 2007 Silverado HD trucks with the LBZ command a significant premium on the used market. They're worth every penny. If you ever find a clean one at a reasonable price, stop reading this and go buy it immediately. I'll still be here when you get back. Number one, the 6.2 LS3.

[00:20:55]The 6.2 LS3 is the best naturally aspirated V8 engine that Chevrolet has ever put into production.

[00:21:03]Full stop. It debuted in the Corvette in 2008 and later appeared in the Camaro SS. It makes 430 horsepower from the factory in a naturally aspirated package and it does so with a simplicity and mechanical integrity that makes it almost unfair to compare with anything else on this list.

[00:21:23]No AFM, no direct injection carbon problems, an iron block that handles heat without drama, an oiling system that works, a proven valve train design that has been refined over decades of LS development. The LS3 rewards proper maintenance with with legendary reliability and rewards enthusiast ownership with one of the most satisfying driving experiences available at any price point. 200,000 mi on an LS3 is a beginning, not an end. I have personally seen LS3 engines with over 300,000 mi that have never been opened.

[00:22:00]The owner changed the oil every 5,000 mi, used full synthetic, kept the cooling system fresh, and the engine simply kept running. This is what Chevrolet engineering looks like when it's done right. So, there you have it.

[00:22:14]11 engines to walk away from and five engines that will change how you think about Chevrolet reliability. Print this list out. Seriously. Take it to the used car lot with you. The difference between a Chevrolet that becomes a lifelong vehicle and one that becomes your most expensive mistake often comes down to knowing exactly which engine is under that hood before you hand over your money. If this video saved you from a bad purchase or helped you understand what you already own, smash that subscribe button and drop a comment below telling me which of these engines you've personally dealt with. I read every single one. I'll see you in the next video.