3.6L DOHC VVT Engine Complete Assembly for 2016-2017 Cadillac CT6

A quick look at your own vehicle makes sure the right engine shows up:

• Verify the 8th digit of the VIN is 'S'
• Confirm the Engine RPO Code is 'LGX' on the Service Parts Identification label
• Verify Drivetrain Type (RWD vs AWD)
• Check for the Engine Oil Cooler (RPO KC4) near the oil filter housing

What the install really takes — plan and budget with confidence:

Special tools this job needs:

• Camshaft holding/retaining plates (GM Tool EN-51360)
• Fuel injector remover/installer tool (GM Tool EN-49248)
• High-pressure fuel line quick-disconnect tools
• Engine hoist
• Heavy-duty subframe table/jack
• Engine support fixture
• Torque angle gauge
• Five-point Torx sockets

Budget for these consumables at install:

• Engine Oil (OE-spec Dexos1 Gen 2 or Gen 3 Full Synthetic 5W-30)
• Oil Filter (ACDelco UPF63R only)
• Coolant (GM-approved Dex-Cool 50/50 pre-diluted)
• Spark Plugs (ACDelco 41-147 gapped to 0.035 inches)
• Upper and lower intake manifold gaskets
• Exhaust manifold gaskets
• Thermostat housing gasket
• Front and rear crankshaft main seals
• Teflon injector seals (if transferring injectors)
• One-time-use high-pressure fuel crossover pipe
• Torque-to-Yield (TTY) bolts (harmonic balancer, flywheel/flexplate, cylinder head, main bearings, connecting rods)

What your vehicle’s computers will need after the swap:

What’s involved: Crankshaft Position (CKP) System Variation Relearn

A Crankshaft Position Relearn must be performed using a GM MDI dealer scan tool or a high-end bi-directional diagnostic scanner. Failing to perform this relearn will cause the ECM to miscalculate engine misfires, triggering a persistent Check Engine Light (typically DTC P0300 or P0315). The vehicle's immobilizer system may also require re-marriage with the ECM.

Pro tips for a smooth first start-up — hand them to whoever does the install:

• AWD Oil Pan and Front Axle Pass-Through: If AWD, the front passenger-side axle shaft passes directly through a cast tube in the upper structural aluminum oil pan. Swapping a RWD engine into an AWD vehicle (or vice versa) requires swapping the upper structural oil pan, which requires removing the front timing cover.
• Torque-to-Yield (TTY) Fasteners: Critical fasteners are one-time-use stretch bolts. Reusing them can cause them to snap or back out under load.
• Fragile High-Pressure Fuel Lines: Stainless steel high-pressure fuel lines must never be bent or reused. Reusing them under 2,000+ PSI fuel pressure will result in severe fuel leaks.
• Timing Chain Pre-Tensioning: It is crucial to follow the correct procedure for releasing the timing chain tensioners to avoid jump-timing on the first startup.

Easy to get right once you know them:

• Ordering the Wrong Drivetrain Configuration (AWD vs. RWD) which requires a costly teardown to swap the upper structural oil pan.
• Using a Standard PF63 Oil Filter instead of the mandated UPF63R, which can blow the seal under high pressure.
• Reusing the Thermostat, which is highly difficult to replace once the engine is installed in the car.
• Skipping the Crankshaft Position Relearn, leading to persistent misfire codes (P0300).
• Reusing Torque-to-Yield (TTY) bolts.
• Not swapping the vehicle's original wiring harness to avoid electrical mismatches.

Not issues with the units on this page — the manufacturer documented these for every engine of this family, wherever you buy one. Handy for your installer: