The 2004 WRX is a legendary turbocharged Subaru that rewards enthusiasts willing to maintain it properly, but punishes those who mod aggressively or skip oil changes. Engine internals and head gaskets are the Achilles' heel, especially on cars with unknown modification or maintenance history.
Head Gasket Failure (EJ205 Turbo)
Common · high severity
Typical onset: 80,000-120,000 mi
Symptoms: External oil seepage around cylinder heads, White exhaust smoke on cold start, Coolant consumption without visible leaks, Overheating under load
Fix: Both head gaskets, resurface heads, timing belt/water pump while in there, ARP studs recommended. 12-16 hours labor depending on shop efficiency and whether heads need machine work.
Estimated cost: $2,200-3,500
Ringland Failure / Cracked Pistons
Occasional · high severity
Typical onset: 60,000-100,000 mi
Symptoms: Sudden loss of power, Loud knock from cylinder 4 (most common), Misfire codes P0304, Excessive blow-by or smoking, Low compression on one cylinder
Fix: Cast pistons crack under detonation (bad tune, low octane, aggressive boost). Requires short block replacement or full rebuild with forged pistons. 18-24 hours labor for short block swap, more for complete rebuild.
Estimated cost: $4,500-7,500
Turbocharger Failure (IHI VF39)
Occasional · medium severity
Typical onset: 100,000-140,000 mi
Symptoms: Whining or grinding noise from turbo, Blue smoke on acceleration, Loss of boost pressure, Check engine light with underboost codes, Excessive shaft play
Fix: Oil starvation or age kills the journal bearings. Replace or rebuild turbo, replace oil feed/drain lines, change oil. 6-8 hours labor for turbo replacement.
Estimated cost: $1,200-2,200
Transmission Synchro Wear (2nd/3rd Gear)
Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Grinding into 2nd gear when cold, Difficult shifts into 3rd under load, Crunching even with full clutch depression, Worse with aggressive driving or missed shifts
Fix: 5-speed manual (not 6-speed STI trans) has weak synchros. Requires transmission rebuild with upgraded brass synchros. 8-12 hours labor for removal, rebuild, reinstall.
Estimated cost: $2,000-3,200
Transmission Mount Failure
Common · low severity
Typical onset: 60,000-90,000 mi
Symptoms: Clunking on shifts or throttle transitions, Excessive drivetrain movement, Vibration through shifter, Visible torn rubber in pitch stop mount
Fix: Pitch stop mount (rear trans mount) tears from spirited driving. Replace with OEM or upgraded polyurethane. 1-2 hours labor, straightforward job.
Estimated cost: $150-350
Banjo Bolt Filter Clogging (Turbo Oil Feed)
Occasional · high severity
Symptoms: Turbo whine or failure without warning, No obvious external oil leaks, Happens after long oil change intervals or contaminated oil
Fix: Tiny filter screen in banjo bolt at turbo oil feed clogs, starving turbo of oil. Many techs remove screen entirely during turbo service. Preventive removal takes 30 minutes if turbo is healthy.
Estimated cost: $50-150
Fuel Pump Failure
Occasional · medium severity
Typical onset: 90,000-130,000 mi
Symptoms: Stumbling or hesitation under hard acceleration, No-start condition after sitting, Whining noise from fuel tank, Lean codes or fuel pressure drop
Fix: In-tank pump wears out, especially if car is run low on fuel frequently. Drop tank, replace pump assembly. 3-4 hours labor.
Estimated cost: $500-800
Owner tips
Use only premium fuel (91+ octane) and change synthetic oil every 3,500-4,000 miles — these engines are unforgiving.
Remove or replace the banjo bolt filter screen at turbo oil feed during ANY turbo service to prevent starvation.
Avoid aggressive tunes or modifications without supporting fueling and a professional dyno tune — ringland failure is real.
Inspect head gasket seepage every oil change after 80k miles; catch it early before overheating causes head warping.
Buy it if you find one bone-stock with documented maintenance and a clean Carfax — avoid modded examples unless you're ready for a rebuild.
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.
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AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE · 23V076000
2023-02-13
Subaru of America, Inc. (Subaru) is recalling certain 2004-2005 Impreza and WRX vehicles that received replacement front passenger air bag inflators under a previous recall. The replacement air bag inflators may have been installed incorrectly.
Consequence: An incorrectly installed inflator may not properly inflate the passenger air bag, increasing the risk of injury during a crash.
Remedy: Dealers will inspect the passenger inflator and if necessary, install a new inflator kit, free of charge. Owner notification letters are expected to be mailed April 14, 2023. Owners may contact Subaru's customer service at 1-844-373-6614. Subaru's number for this recall is WRF-23.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE · 20V001000
2020-01-02 · EA15001
Subaru of America, Inc. (Subaru) is recalling certain 2009-2013 Forester, 2003-2006 Baja, 2004-2011 Impreza, 2004-2014 WRX (STI included), 2003-2014 Legacy and Outback, and 2005-2006 Saab 9-2X vehicles originally sold, or ever registered, in the states of Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands (Saipan), and the U.S. Virgin Islands or "Zone A."
These vehicles had their passenger frontal air bag inflators previously replaced under a prior recall using inflators of the same design. The inflators may explode due to propellant degradation occurring after long-term exposure to high absolute humidity, temperature and temperature cycling.
Consequence: An inflator explosion may result in sharp metal fragments striking the driver or other occupants resulting in serious injury or death.
Remedy: Subaru will notify their owners. General Motors will notify Saab owners. Dealers will replace the passenger air bag inflators with alternate inflators, free of charge. The recall began January 7, 2020. Subaru Owners may contact Subaru customer service at 1-844-373-6614. Saab owners may contact the Saab Customer Assistance Center at 1-800-955-9007. Subaru's number for this recall is TKA-20.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE · 20V002000
2020-01-02 · EA15001
Subaru of America, Inc. (Subaru) is recalling certain 2009-2013 Forester, 2003-2006 Baja, 2004-2011 Impreza, 2004-2014 WRX (including STI), 2003-2014 Legacy and Outback, and 2006 Saab 9-2X vehicles originally sold, or ever registered, in the states of Arizona, Arkansas, Delaware, District of Columbia, Illinois, Indiana, Kansas, Kentucky, Maryland, Missouri, Nebraska, Nevada, New Jersey, New Mexico, North Carolina, Ohio, Oklahoma, Pennsylvania, Tennessee, Virginia, and West Virginia or "Zone B."
These vehicles had their passenger frontal air bag inflators previously replaced under a prior recall using inflators of the same design. The inflators may explode due to propellant degradation occurring after long-term exposure to high absolute humidity, temperature and temperature cycling.
Consequence: An inflator explosion may result in sharp metal fragments striking the driver or other occupants resulting in serious injury or death.
Remedy: Subaru will notify their owners. General Motors will notify Saab owners. Dealers will replace the passenger air bag inflators, free of charge. The recall began January 7, 2020. Subaru owners may contact Subaru customer service at 1-844-373-6614. Saab owners may contact the Saab Customer Assistance Center at 1-800-955-9007. Subaru's number for this recall is TKB-20.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE · 20V003000
2020-01-02 · EA15001
Subaru of America, Inc. (Subaru) is recalling certain 2009-2013 Forester, 2003-2006 Baja, 2004-2011 Impreza, 2004-2014 WRX (including STI), 2003-2014 Legacy and Outback, and 2005-2006 Saab 9-2X vehicles originally sold, or ever registered, in the states of Alaska, Colorado, Connecticut, Idaho, Iowa, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New York, North Dakota, Oregon, Rhode Island, South Dakota, Utah, Vermont, Washington, Wisconsin, and Wyoming or "Zone C."
These vehicles had their passenger frontal air bag inflators previously replaced under a prior recall using inflators of the same design. The inflators may explode due to propellant degradation occurring after long-term exposure to high absolute humidity, temperature and temperature cycling.
Consequence: An inflator explosion may result in sharp metal fragments striking the driver or other occupants resulting in serious injury or death.
Remedy: Subaru will notify their owners. General Motors will notify Saab owners. Dealers will replace the passenger air bag inflators, free of charge. The recall began January 7, 2020. Subaru owners may contact Subaru customer service at 1-844-373-6614. Saab owners may contact the Saab Customer Assistance Center at 1-800-955-9007. Subaru's number for this recall is TKC-20.
EXTERIOR LIGHTING · 06E060000
2006-06-29
CERTAIN AAI MOTORSPORTS COMBINATION LAMPS SOLD AS REPLACEMENT LAMPS FOR USE ON THE ABOVE LIST PASSENGER VEHICLES. COMBINATION LAMPS NOT EQUIPPED WITH AMBER SIDE REFLECTORS FAIL TO CONFORM WITH THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 108, "LAMPS, REFLECTIVE DEVICES, AND ASSOCIATED EQUIPMENT."
Consequence: LACK OF AMBER SIDE REFLECTORS IN THE LAMPS WILL DECREASE LIGHTING VISIBILITY TO OTHER DRIVERS AND MAY POSSIBLY RESULT IN A VEHICLE CRASH
Remedy: AAI MOTORSPORTS WILL NOTIFY OWNERS AND REPLACE THE LAMPS FREE OF CHARGE. THE RECALL BEGAN ON AUGUST 1, 2006. OWNERS MAY CONTACT AAI MOTORSPORTS AT 909-923-9188.
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