Trailblazer Forum banner
1 - 5 of 5 Posts

2021Trailblazer RS AWD Scarlet Red Metallic
871 Posts
Discussion Starter · #1 · (Edited)
Here is what I've dug up so far on the 1.3T (L3T) engine. The 1.2T (LIH) is almost identical to the 1.3T, just a little smaller with less hp/tq.


1.3T (L3T) Engine Overview
The 1.3T is an advanced, power dense, inline three-cylinder engine, producing 115 hp (86 kW) per liter. It is the built off the new cylinder set strategy (CSS) engine architecture, optimizing efficiency and performance. The new 1.2T and 1.3T engines were designed through a partnership with GM's former Opel subsidiary (now owned by PSA), and the Shanghai Automotive Industry Corporation (SAIC), and MG Motor. GM’s new three-cylinder engines are built at its Ramos Arizpe plant in Mexico and are then shipped to GM Korea’s Bupyeong facility in Incheon, South Korea, which is building both the 2020-2021 Buick Encore GX and the related 2021 Chevrolet Trailblazer.

Engine Specifications 1.3T (L3T)
• Engine Type: Inline three cylinder
• Displacement: 1.35 L, 1341 cc, 81.8 CID (cubic inch displacement)
• Bore x Stroke: 79 mm x 91.2 mm
(3.11 in x 3.59 in)
• Block Material: Aluminum
• Cylinder Head Material: Aluminum
• Valve Configuration: Dual overhead camshaft (DOHC) with variable valve timing (VVT)
• Valves per cylinder: 4
• Fuel System: Spark ignited direct injection (SIDI)
• Compression Ratio: 10.0:1
• Firing Order: 1–2–3
• Horsepower @5600 RPM: 155 hp (115 kW)
• Torque @1600 RPM: 174 lb ft (236 Nm)

Engine Specifications 1.2T (LIH)
• Engine Type: Inline three cylinder
• Displacement: 1.2L, 1199 cc, 73.2 CID (cubic inch displacement)
• Bore x Stroke: 75 mm x 90.5 mm
(2.953 in x 3.563 in)
• Block Material: Aluminum
• Cylinder Head Material: Aluminum
• Valve Configuration: Dual overhead camshaft (DOHC) with variable valve timing (VVT)
• Valves per cylinder: 4
• Fuel System: Spark ignited direct injection (SIDI)
• Compression Ratio: 10.0:1
• Firing Order: 1–2–3
• Horsepower @5000 RPM: 137 hp (102 kW)
• Torque @2500 RPM: 166 lb ft (225 Nm)

Engine Block
The aluminum alloy engine block is made by high pressure die casting with three cast-in-place iron cylinder liners called cylinder set strategy (CSS). There are four crankshaft bearings with the thrust bearing being located on the third bearing from the front of the engine. The lower structural extension forms the lower portion of the crankcase to promote cylinder block rigidity and reduce engine noise and vibration.

Cylinder Head
The cylinder head is a dual overhead camshaft design made of cast aluminum alloy. Each combustion chamber contains four valves and is designed for increased swirl efficiency of the incoming air charge to maximize gasoline combustion efficiency. The exhaust manifold is integrated into the cylinder head. The fuel injectors are located under the intake ports.

Balance Shaft Assembly
The single balance shaft is internal to the engine block. The oil pump is attached to the lower structural extension of the engine block. The balance shaft and oil pump are driven by the balance shaft chain. The engine oil pump supplies pressure to the hydraulic tensioner, which provides the chain's tension. This design promotes the maximum effectiveness of the balance shaft system and further reduces engine noise and vibration.

The crankshaft is made of forged micro alloy steel. Six counterweights have been scalloped for mass reduction and precision engine balance. A harmonic balancer controls torsional vibration.

Pistons and Connecting Rods
The cast aluminum pistons in the 1.3L (L3T) engine are a lightweight and low friction design with a recessed top and a barrel shaped, graphite-coated skirt. Its cast iron top ring provides added strength. The pistons use two compression rings and one oil control ring assembly. The chromium steel pins are designed to be full-floating and must be serviced with the pistons as an assembly. The powdered metal connecting rods are fractured at the connecting rod journal and machined for proper clearance.

Lower Oil Pan
The lower oil pan is made of plastic and is attached at the engine block lower structural extension. The oil pan must not be used for lifting the engine as noted by the icon on the pan. These oil pans are equipped with M5 jackscrews for easy removal. Once properly cleaned, the oil pan is reusable.

Lubrication System
The lubrication system includes a continuously variable oil pump, an oil filter bypass valve, and an oil heat exchanger.

Oil Pump and Oil Control Valve
The continuously variable oil pump has an oil control valve that controls the oil flow to the oil pump, thereby controlling the oil pressure in the main gallery. The oil control valve is controlled by the engine control module.

Oil Filter Bypass Valve
The lubrication system also includes an oil filter bypass valve located inside the filter thread nipple. This bypass valve is used to continue providing oil to the engine in the event the oil filter becomes plugged.

Oil Heat Exchanger
The oil cooler heat exchanger is mounted to the lower right side of the engine and is used to heat or cool engine oil.

The engine has two camshafts, one for the intake valves and another one for the exhaust valves. The camshafts are driven using a Belt-in-Oil system. This system reduces noise and friction compared to timing chains and dry belt systems. Both the timing belt and the oil drive belt have a change interval of 150,000 miles (240,000 km) or 15 years.

Camshafts Actuator System
The camshaft actuator system on the cylinder set strategy (CSS) engine is much like the camshaft actuator systems found on other GM engines. This system enables the engine control module to change camshaft timing while the engine is running. The intake and exhaust camshaft position actuator assemblies vary the camshaft position in response to directional changes in oil pressure. Modifying camshaft timing under varying engine load provides better power, fuel economy, and lower emissions.

Camshaft Position Sensors
There are two camshaft position sensors, providing feedback to the engine control module. These sensors are integrated into the camshaft cover.

Active Thermal Management Cooling System
The cooling system on the cylinder set strategy (CSS) engine is completely new and different. A new system called active thermal management is now used to control the coolant temperature. This system which features an electric water pump helps the engine and transmission warm up faster and achieve its optimal temperature, improving performance and efficiency. Active thermal management sends heat where it is needed to reduce friction and heat the passenger compartment. Likewise, this system cools the engine and transmission when necessary for high power operation.

Crankcase Ventilation System
The crankcase ventilation system incorporates a pre-separator in the left side of the engine block below the coolant control valve. As crankcase gasses enter the pre-separator, oil separates and drains back to the oil pan through two oil drain channels in the block. The blow by flows internally from the pre-separator through block and head into the fine separator.

Ignition System
The ignition system of the 1.3L (L3T) engine is a coil per plug system featuring 14 mm spark plugs that are installed seven degrees offset in the cylinder head. The camshaft position sensors are located on the camshaft cover, and the crankshaft position sensor is located on the left rear of the engine with the target wheel attached to the rear of the crankshaft. Two knock sensors are located on the intake side of the engine.

Fuel Injection System
The 1.3L (L3T) engine is equipped with a spark ignited direct injection system (SIDI) and consists of three direct injection fuel injectors that mount in the side of the cylinder head below the intake ports. The injector tip size is now 6 mm, so it requires a new seal installer and sizer. The high pressure fuel pump mounts to the rear of the cylinder head and is driven by a hydraulic roller lifter, which is in turn driven by the intake camshaft. The fuel system is capable of producing 35 MPa (5076 PSI).

Evaporative Emission Purge Pump
The evaporative emission purge pump located on the left rear of the engine. This pump is necessary because the purge capacity is reduced by technologies that improve fuel economy. The purge pump is required to increase the purge volumes to meet Low Emission Vehicle 3 Evaporative Emission requirements. This pump has an integral pressure sensor and is controlled by the engine control module.

The L3T engine uses a turbocharger which has been optimized to reduce turbo lag and give the engine more immediate throttle response, capable of a maximum boost of 1.5 bar (22 PSI). The engine control module controls the turbocharger's electric wastegate and bypass valves.

I will add more info as I find it. If anyone has additional info post it here and I'll add it and if you see any info that's wrong please let me know and I'll delete or correct it.


Super Moderator
2021 TB Zues Bronze Activ
622 Posts
Good info.

29 Posts
That lil turbo peaks at 22 PSI? Damn, that's actually pretty impressive.

Edit - Many thanks for sharing this info!
1 - 5 of 5 Posts