The 2017 Acura RLX is a flagship sedan built on Honda's refined J35 V6 platform (standard or Sport Hybrid SH-AWD). While generally reliable, it suffers from specific transmission cooling issues and, in rarer cases, catastrophic engine bearing failures that can total the powertrain.
Transmission Oil Cooler Failure
Common · high severityTypical onset: 60,000-90,000 mi
Symptoms: Transmission fluid leaking from cooler lines or cooler itself, Transmission overheating warnings on dash, Harsh or delayed shifting after sustained highway driving, Pink or milky transmission fluid indicating coolant cross-contamination
Fix: Replace transmission oil cooler assembly and flush both cooling system and transmission. Requires front-end disassembly to access cooler. 4-6 hours labor plus parts and fluids.
Estimated cost: $1,200-2,000
Engine Bearing Failure (Connecting Rod and Main Bearings)
Rare · high severityTypical onset: 80,000-130,000 mi
Symptoms: Knocking or rattling noise from bottom end, especially on cold starts, Sudden loss of oil pressure, Metallic debris in oil during changes, Check engine light with low oil pressure codes
Fix: Complete engine rebuild or replacement required. Rod and main bearing failures on J35Y engines stem from inadequate oil change intervals or oil pump issues. Expect 20-30 hours for in-frame rebuild, more for short block swap.
Estimated cost: $6,500-12,000
Head Gasket Seepage (Both Banks)
Occasional · medium severityTypical onset: 100,000-150,000 mi
Symptoms: Slight coolant smell from engine bay, Minor oil residue on cylinder head exterior near gasket mating surface, Slow coolant loss with no visible external leaks, No overheating but may see slight temperature creep under load
Fix: Replace both head gaskets, surface heads if warped, new head bolts. Timing belt service typically bundled since you're already there. 12-16 hours labor.
Estimated cost: $3,200-4,800
Transmission Mount Deterioration
Common · low severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive vibration at idle in Drive, Visible cracks or separation in rubber mount material, Transmission sag visible from underneath
Fix: Replace transmission mount(s). The rear mount typically fails first. 2-3 hours labor with proper support equipment.
Estimated cost: $400-700
Hybrid Battery Pack Degradation (Sport Hybrid SH-AWD only)
Occasional · high severityTypical onset: 120,000-160,000 mi
Symptoms: Reduced electric-only range or EV mode unavailable, Check hybrid system warning on dash, Diminished fuel economy compared to earlier ownership, Battery cooling fan running excessively
Fix: Hybrid battery module replacement or refurbishment. Honda/Acura warranty covered to 8yr/100k mi in most states, so this hits later owners. 6-8 hours labor for replacement.
Estimated cost: $3,500-6,000
Fuel System Contamination Issues
Rare · medium severitySymptoms: Rough idle or misfires after fueling, Fuel smell from tank area, Check engine light with fuel trim codes, Difficulty starting after sitting
Fix: Fuel filter clogging or contamination from tank corrosion. Filter is in-tank on this platform, requires tank drop. 3-5 hours labor depending on fuel level and rust.
Estimated cost: $600-1,100
Buy the standard V6 under 80k miles with full service records; avoid high-mileage hybrids unless battery health is verified and transmission cooling system has been preemptively serviced.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.