3.5L V6 SOHC i-VTEC Engine Complete Assembly for 2014-2020 Acura RLX

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

• Verify VIN 6th digit is '2' (designates AWD Sport Hybrid chassis).
• Verify VIN 8th digit is '9' (designates 3.5L V6 Hybrid JNB1 engine).
• Verify engine code stamp on the front of the block says 'JNB1' or 'JNB'.

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

Special tools this job needs:

• High-Voltage Safety Equipment (1,000V insulated gloves, safety glasses, insulated tools)
• Engine Hoist/Crane and Load Leveler
• Honda/Acura Diagnostic Scan Tool (HDS)
• Heavy-Duty Subframe Adapter/Cradle
• Specialized crankshaft pulley holder tool

Budget for these consumables at install:

• Timing Belt Kit (timing belt, hydraulic tensioner, idler pulley, adjuster pulley)
• Water Pump
• Spark Plugs (6 new OE-spec iridium)
• Gaskets (Intake manifold, exhaust manifold, thermostat, oil drain plug washer, rear main seal)
• Engine Oil & Filter (0W-20 full synthetic, 4.5 quarts)
• Coolant (Honda/Acura Type 2 Blue pre-mixed)

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

What’s involved: Crankshaft Position (CKP) Pattern Relearn / Immobilizer Re-marriage

sources differ: Arm 1 states only a CKP Relearn is required if retaining the original ECU (no immobilizer re-marriage needed), while Arm 2 states an immobilizer re-marriage is required because the donor ECU is used. Cautious choice: Yes, dealer tool required for both CKP relearn and potential immobilizer programming.

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

• High-Voltage Safety: Must disable the high-voltage hybrid system by pulling the High-Voltage Service Plug behind the rear seatback and waiting 10 minutes before starting work.
• Dual Cooling Loops: The vehicle has separate cooling systems for the engine and the hybrid inverter. Both must be bled; the inverter loop requires a scan tool command to run the electric water pump.
• Active Engine Mounts (ACM): Electronically controlled, fluid-filled mounts are fragile and expensive; handle with care.
• Subframe Drop: Standard procedure requires dropping the engine and transmission together from the bottom of the vehicle.
• Timing Belt Pulley Shim: Ensure the drive pulley shim is correctly positioned to prevent belt rubbing and chirping.
• Crankshaft Pulley Bolt: Extremely tight; requires a special heavy-duty holder tool and high-torque impact wrench.

Easy to get right once you know them:

• Confusing the Hybrid (JNB1) and Non-Hybrid (J35Y4) Engines: Standard RLX uses J35Y4 which is not interchangeable with the hybrid JNB1.
• Not Bleeding the Hybrid Inverter Cooling Loop: Leads to air pockets, causing the hybrid system to overheat and enter limp mode.
• Failing to Disable the High-Voltage System First: Can blow expensive high-voltage fuses or cause severe injury.
• Reusing the Rear Main Seal: Skipping replacement during install leads to expensive labor costs if it leaks later.
• Overfilling the Oil: JNB1 takes exactly 4.5 quarts with filter; overfilling causes foaming, oil starvation, and spun rod bearings.
• Not Budgeting for Immobilizer/Key Reprogramming: Assuming a 'crank, no-start' condition is mechanical when it is actually the security system blocking the start.

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: