Engines are the beating heart of every combustion-powered vehicle. Through thousands of repeated, minuscule explosions, it creates more than enough grunt to shove some 2-tonne slab of metal into the sunset. More often than not, engines are typically fairly dependable, without a lot in there that could break in half. That is, until you take a look at all the GM 1.5 turbo engine problems, and weep.
Back in 2014, General Motors made a big splash with the appropriately named Small Gasoline Engine (SGE). This line-up of small-displacement motors, ranging from just 1.0-liter to a mere 1.5-liter, marks a huge leap forward for GM. At the time, they’re mostly known for big, gas-guzzling LS V8s fitted into muscle cars. Or, the myriad of LS V8 swaps out there, even to puny cars like the MX-5 Miata.
By now, GM showed that they could make efficient, ingenious, but nonetheless potent powertrains. It was fitted into most of GM’s portfolio at the time. You can find these SGE motors inside of models by Buick, Opel, or GM’s China-only marque, Roewe. Yet, despite the clever nature of these engines, could they also be badly flawed? Let’s take a peek at all the GM 1.5 turbo engine problems, and find out…
What Is GM’s SGE Series, Anyway?
Before we get into the GM 1.5 turbo engine problems, some context might help. So, what’s about this GM SGE engine family, then. At the turn of the 2010s, General Motors realized the design and build a new series of engines, made with efficiency in mind. Good MPG figures alone aren’t enough. Thus, their engine needed to also be decently performant, lower emissions, and reduce the NVH to a minimum.
The latter stands for Noise, Vibrations, and Harshness, which defines the unpleasant or discomforting sounds and vibrations that you’ll experience while driving. With all those characteristics in mind, GM succeeded in creating a lightweight, modestly powerful, fuel-efficient, low-emissions, and comforting engine to fit the smaller end of their stable. In other words, GM’s smaller and cheaper vehicles.
GM’s SGE is also marketed as part of their ‘Ecotec’ (or in some other markets, ‘Microtec’) engines. On top of that, General Motors also sells this engine to their Chinese partner, SAIC motors. Where, SGEs can be found on SAIC-made cars, too. In particular, there are four distinct configurations that an SGE engine can be had with. This includes our culprit for GM 1.5 turbo engine problems:
- 1.0-liter (999cc, 61.0-cubic inch), turbocharged inline-3
- 1.1-liter (1,118cc, 68.2-cubic inch), inline-3
- 1.4-liter (1,399cc, 85.4-cubic inch), turbocharged inline-4
- 1.5-liter (1,490cc, 90.9-cubic inch), turbocharged inline-4
To make it happen, GM has engineered an abundance of new and innovative technologies into their SGE collection of engines. Here are some of the most notable inclusions:
What Are The Key Features Of GM’s SGE?
- All of the aforementioned configurations (and many other unique or specialized variations of this) are made from just two engine blocks. This encompasses their 3- and 4-cylinder versions. A key aspect of the SGE Ecotec engine is its modularity, whereby components can be readily interchanged if needed. Hence, they all have the same 2.91-inch (74mm) bore, and 3.19-inch (81mm) bore spacing.
- The direct injection fuel rails are mounted with bushings onto the cylinder head and valve cover. This can aid in reducing the vibrations and loud ticking sounds from the injectors. Consequently, GM has claimed that their 1.0-liter SGE engine is 25% quieter than Ford’s similar 1.0-liter engine in the Fiesta.
- In addition, GM’s other attempts to reduce noise from this engine include using a bed-plate engine block. This helps to increase stiffness – thus reducing any rattling or loose sounds – and use a stiffened aluminum cam cover. Also, the inline-3 engines get a counter-rotation balancing shaft. Bolted onto the oil pump, it can further lower radiated noise, as well as let it idle more smoothly.
- All turbocharged SGE engines carry a Mitsubishi Heavy Industries one-stage, single-scroll turbo. These can spool up very rapidly, with around 90% of their peak torque arriving between 1,500 to 5,000RPM. This is fairly low in the rev range. Plus, peak power is within the 5,600 to 6,000RPM range. The turbo is also installed close to the cylinders, able to dole out speedy torque and throttle response.
- The engine is made mostly out of aluminum (block and head) and uses a composite intake manifold. This is all in the name of saving as much weight as possible, and the SGE is overall a small and light motor. It only weighs 216lbs (98kg) for the bigger 1.4-liter engine, which is 44lbs (20kg) lighter than its predecessor.
Which Cars Have Been Fitted With GM’s 1.5 Engines?
The SGE series of engines are fitted across the whole of GM’s model range, including its subsidiaries, at the time. This was made all the more appealing in certain markets, where alternative fuels can be used. Accordingly, SGE engines could be powered with CNG (compressed natural gas), LPG (liquified petroleum gas), as well as E85 and E100. Of course, most were used with simple gasoline.
Depending on which GM-owned brand you’re shopping with, the specifications of your SGE motor will differ, too. For example, the same SGE engines used by Opel (and its UK-specific brand, Vauxhall) can have varying modifications made to them. That’s when compared to China or US-market SGE motors. For now, though, we’ll stick with the GM SGE Ecotec engines that are sold widely here in the US.
While also focusing primarily on the 1.5-liter turbocharged variant, which is the subject of this guide on the GM 1.5 turbo engine problems. Specifically, a ‘GM 1.5 engine’ can be any one of three distinct forms. These would be the L3A, LFV, and LYX. Here’s a round-up of their specifications, and what cars were they optioned with…
GM 1.5 (Not) Turbo Inline-4 Engine – L3A (2016 To Present)
We’re only including this for comparison’s sake, as the L3A is the sole GM 1.5 engine that isn’t fitted with a turbocharger. It’s naturally-aspirated, but nevertheless includes a similar direct injection like the other SGE engines. They feature a redline at 6,000RPM and were first unveiled for the Chevy Volt.
- Chevy Volt (2016-Present): 100hp (peak power at 5,600RPM), and 130lb-ft of torque (peak torque at 4,300RPM)
- Buick Vette 5 (2017-2019): 106hp (peak power at 5,800RPM), and 102lb-ft of torque (peak torque at 4,400RPM)
- MG 5 (2020-Present): 112hp (peak power at 6,000RPM), and 111lb-ft of torque (peak torque at 4,500RPM)
GM 1.5 Turbo Inline-4 Engine – LFV (2016 To Present)
The first of the actually-turbocharged GM 1.5 engines is the LFV. It featured a cast aluminum DOHC design. And, it had a lower compression ratio of 10.1:1 (compared to 12.5:1 in the L3A). This variant of the SGE redlines at 6,500RPM, and comes with automatic start-stop functionality.
- MG HS (2018-Present): 162hp (peak power at 5,600RPM), and 184lb-ft of torque (peak torque at 1,700 to4,400RPM)
- Chevy Malibu (2016-Present): 163hp (peak power at 5,700RPM), and 184lb-ft of torque (peak torque at 2,000 to 4,000RPM)
- Buick LaCrosse (2016-Present): 169hp (peak power at 5,600RPM), and 184lb-ft of torque (peak torque at 1,700 to 4,000RPM)
- Buick Envision (2016-Present): 169hp (peak power at 5,600RPM), and 184lb-ft of torque (peak torque at 1,700 to 4,000RPM)
- MG 5 LE (2020-Present): 171hp (peak power at 5,600RPM), and 203lb-ft of torque (peak torque at 1,750 to 4,000RPM)
- MG 6 Pro (2021-Present): 181hp (peak power at 5,500RPM), and 210lb-ft of torque (peak torque at 1,500 to 4,000RPM)
GM 1.5 Turbo Inline-4 Engine – LYX (2018 To Present)
A slight update from the LFV, we have GM’s LYX-generation of 1.5 turbo engines. Once again, it has a familiar direct injection, cast aluminum, DOHC design. Even the compression ratio remains similar, at 10.0:1.
- MG HS FFV (2018-Present): 162hp (peak power at 5,600RPM), and 184lb-ft of torque (peak torque at 1,700 to 4,400RPM)
- MG HS PHEV (2020-Present): 284hp (peak power at 5,500RPM), and 354lb-ft of torque (peak torque at 1,700 to 4,300RPM)
- Chevy Equinox (2018-Present): 170hp (peak power at 5,600RPM), and 203lb-ft of torque (peak torque at 2,000 to 4,000RPM)
- GMC Terrain (2018-Present): 170hp (peak power at 5,600RPM), and 203lb-ft of torque (peak torque at 2,000 to 4,000RPM)
What Are The Most Common GM 1.5 Turbo Engine Problems?
As clever as it may be deep inside, the frequency of GM 1.5 turbo engine problems might suggest that it can also be a problematic motor. We’ll focus predominantly on the 1.5 turbocharged models, that is the LFV and LYX engines. Moreover, we’ll also narrow down our guide to 1.5 configurations that are specifically sold here in the US. In short, the GM 1.5 engines fitted in Buicks, Chevys, and GMCs.
Among the former, Chevrolet, had the most commonly reported GM 1.5 turbo engine problems of the bunch. Some of these issues, in a nutshell, include experiencing turbocharger failure if you’re driving in cold weather. Not to mention, the myriad of other issues, such as the erratic oil pressure readings. And, the Check Engine Light (CEL) going off far too many times.
These are the most noteworthy GM 1.5 turbo engine problems, among a sea of other miscellaneous woes. So, here’s an in-depth look at each of these GM 1.5 turbo engine problems…
1. Turbocharger Failure At Lower Temperatures
Another horrendous issue as part of the collection of GM 1.5 turbo engine problems includes how the turbocharger would fail at colder temperatures. This can, in effect, prevent you from driving your car at all. And even if you’re able to get it going, it can leave a significant impact on your performance, as well as driveability. Worse, this issue can begin appearing with minimal mileage clocked in.
As the turbocharger freezes and fails, it might otherwise prompt your car to activate its ‘limp home’ mode, which sharply restricts the speed you’re able to drive. Reading into the forums, we’ve noted a story from one owner, who had their turbo fail in the middle of a long drive. It failed on them more than once, which forced them to abandon their car, only to have it affect their loaner car, too.
Another owner saw a “reduced power” message pop up on their dash, before losing power from the engine completely. In other cases, owners were nearly caught in rear-end collisions or horrible near misses, as their vehicles lost power. Unfortunately, this turbocharger issue is far too common, given its seriousness. Although, its victims are mostly those that live and drive in colder weather.
Apparently, moisture from the intakes can freeze up at lower temperatures. Thus, blocking airflow to the turbos. It should clear up once the intakes and engine heat up more. A Canadian owner noted the temperature to be as low as -45°C. There hasn’t yet been a permanent fix, other than some dealers advising owners to buy a radiator cover. They could then block off the turbo’s intercooler airflow.
2. Oil Pressure Readings Forever Stay In Flux
Oil pressure is important to gauge the flow of oil into the engine, which affects lubrication as well as cooling. Generally, most of us needn’t have to worry about oil pressure. That is unless you’re a victim of GM 1.5 turbo engine problems. They tend to have a habit of never keeping oil pressure at an even level. Sometimes, it might not have enough pressure, or at other times, far too much of it.
Just for context, here’s an excerpt from our guide on low oil pressures, to see how much PSI is too low or high for a typical car engine:
- 20-30 PSI (oil pressure while idling)
- 25-65 PSI (normal oil pressure)
- 45-70 PSI (it gets pressurized while driving)
- >80 PSI (too much oil pressure)
- <20 PSI (too little oil pressure)
Alas, GM’s 1.5 turbo engines don’t follow these general guidelines and have oil pressures that could fluctuate nearly all of the time. More often than not, reaching dangerous levels. One owner saw how their 1.5 engines could see the oil pressure skyrocket from 30PSI to 70PSI, even while idling or driving steadily. This then ties in with heavy oil consumption or oil burning.
While it’s very common, remember that the oil pressure can fluctuate very randomly. So much so, it appears that GM’s dealerships and technicians couldn’t replicate the problem. They’d report back to owners that everything is normal, and it’s possibly a feature of the engine to run at too high or low of oil pressure. Still, owners remain concerned about long-term damage and wear to the engine.
3. Check Engine Light Appears Regularly
As scary as it might seem, the Check Engine Light (CEL) is quite useful. It can alert you early on with a possible issue with your vehicle. You could then take this as an opportunity to have it checked out as quickly as you can. At least, before the problems snowball into something far more serious. A CEL can even light up in your dash for seemingly simple issues, such as not tightening your gas cap properly.
In the case of those cars fitted with a GM 1.5 turbo engine, it seems as though the CEL can appear far too frequently, even when there aren’t any problems. We’d call them false positives. Many owners of vehicles with GM’s 1.5 turbo engines spotted the CEL showing up, with no other noticeable signs and symptoms of underlying issues. This was confirmed when diagnosed with an OBD scanner.
Once again, no error codes popped up, which means there aren’t any problems. Yet, it hasn’t failed to induce fear in those owners, who think that something bad is brewing with their GM cars. This does appear intermittently, making it hard for mechanics to replicate the issue. Therefore, there hasn’t yet been a permanent solution to this issue of the check engine light flashing or blinking regularly.
Owners are left with two fixes, as GM themselves never released a patch. The first is to bring along a diagnostics (OBD) scanner tool. Once a CEL does show up, plug that into your car, and see if there are any errors. If there aren’t, you could easily clear out the CEL from flashing on your dash. The other fix, as recommended by GM dealers, is to simply take the risk of ignoring the CEL altogether.
4. Cracked Or Melted Pistons, And Terrible Blow-By
When GM’s new 1.5 turbo engines were first unveiled and went into mass production with the Chevy Malibu, severe problems started appearing. The most memorable among them is how these engines can run so hot, due to poor cooling and engine management, that they could melt. Specifically, the pistons themselves could melt, possibly turning your 1.5 inline-4 engine into an operational inline-3.
Subsequently, this issue could create rough idling, shuddering, as well as horrible amounts of blow-by. Some have speculated to poor mapping with the ECM or fuel-air flow. This otherwise causes the engine to run lean (too much air, not enough fuel to burn). It’s exacerbated by the inclusion of the turbos, as the engine repeatedly goes in and out of boost, further adding heat and strain.
Some other symptoms include seeing smoke from the engine, as well as burning oil (or heavy oil use and consumption). Misfires could also happen, as you’ll notice a Check Engine Light, on top of poor performance. The good news here is that this pre-ignition failure, which prompts a cracked or melty piston, isn’t as widespread. GM has identified the root cause to be the engine’s SPI system.
Or, ‘stochastic pre-ignition‘. It can be easily fixed by heading over to a GM dealership and getting the engine control module (ECM) reprogrammed. According to a bulletin issued by GM to its technicians and dealerships, the motor oil should also be changed. They specifically name the ACDelco Dexos 1 full-synthetic oil. Alternatively, Mobil 1 oil for those affected cars sold in Canada.
GM’s 1.5 Vs. 2.0 Turbo Engines, Which One’s Better?
Given how GM’s 1.5 turbo engine has been fitted to many popular and top-selling cars in the US, such as those fitted in the Chevy Equinox and GMC Terrain, owners have made a comparison with the other engines on offer, too. Speaking of sibling rivalry, the 1.5’s arch-nemesis is GM’s more meaty 2.0-liter turbocharged engine. The latter is an option on higher-end trims, where the 1.5 is standard fitment.
So, which one is better, the 1.5 turbo, or the 2.0 turbo, both from GM? Well, there are a few angles and arguments to tackle this by:
- For reliability’s sake, the 2.0-liter turbo engines seem to suffer from fewer problems than the 1.5. Yes, the 2.0 isn’t immune to issues, which fewer of them crop up compared to the 1.5.
- If you’re planning to go off-road, the 2.0 is the better choice for more power and torque. Fitting the 1.5 engine with a 4WD setup isn’t sufficient, with barely enough grunt for most trails. If you’re mostly concerned with on-road performance, the 1.5 engine with 2WD should be decent.
- Given that it’s a bigger engine, the 2.0 is undoubtedly less fuel-efficient than the small 1.5. Even with a conservative application of the accelerator pedal, GM’s 2.0 engines can sip very heavily on gas.
- For general performance, owners have reported substantial lag with the 1.5 engines. It’s unclear whether this is an issue with the throttle and ECU mapping, or the turbochargers themselves. For a more spirited response, you’re better off with the 2.0.
Well then, that just about rounds up our look at GM 1.5 turbo engine problems. So, do they deserve a bad reputation? Not entirely, no. Sure, GM’s 1.5 engines are susceptible to a few common issues, like turbo failures, cracked pistons, fluctuating oil pressure, and triggered CEL. The most serious has to be concerning its cracked or melted pistons, which don’t occur frequently, and a fix has been issued.
So, how about the rest? Unfortunately, there’s no thorough fix for the turbocharger failures. Our only recommendation would be to avoid picking this engine if you regularly drive in colder climates. As for the Check Engine Light issue, it’s not that terrible of a deal. You could remedy this by bringing along a simple OBD reader, and resetting the CEL. We’re still not sure if that oil pressure issue is normal, or not.
In summary, the GM 1.5 turbo engine problems don’t indicate this being an extremely unreliable and expensive engine to run. While it’s short on power for those hardy off-road excursions, it’s more than enough for day-to-day driving. And, it’s quite fuel-efficient, too. Its reliability troubles won’t destroy or scrap the engine, either. Should issues appear, they’re relatively inexpensive and simple to solve, as well.
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