KiaOptima2004Overview/kia/optima/2004/base/

2004 Kia Optima

Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 2004 Optima.

Body PASSENGER CAR

The 2004 Kia Optima is a passenger car built on a midsize sedan platform, powered by a four-cylinder engine that utilizes a 4.5-quart oil capacity with recommended viscosities of 20W-40, 20W-50, or 10W-30 depending on operating conditions. During a production year that saw 225 total owner complaints with the primary issue centering on latches, locks, and linkages, the model experienced one recall, placing it in an early phase of the nameplate's evolution. When viewed across the broader 2001-2020 complaint trajectory—where incidents peaked at 1,371 in 2013 and dipped to a low of 75 in 2010—the 2004 Optima falls within a period of relatively moderate reliability performance before the significant fluctuations that would later characterize the model's history.

Model year2020201920182017201620152004

Quick specs

Fluid capacities, tune-up values and fuel economy at a glance.

Engine oil capacity4.5 qtOEM · verified
Engine oil type20W-40 / 20W-50 / 10W-30 APIOEM · verified
Lug nut torque66-81 ft-lbsOEM · verified

Fitment & sizes

Replacement part sizes and factory part numbers — battery, bulbs, filters and belts.

From the factory this vehicle uses a BCI 124R · 600 CCA battery. Each part links to every other vehicle that shares it, so a part you already stock may fit more of your fleet than you'd expect.

Battery groupBCI 124R · 600 CCAOEM · verified
Tail / brake / turnFUSEOEM · verified

Performance & power Independent road tests

0–60 mph, quarter-mile, horsepower and torque from independent road tests.

Independent road tests for the Optima of this era, listed by trim and engine — this page spans more than one engine, so no single horsepower figure is shown.

8.3–9.0 sec0–60 mph (tested)quickest 8.30 sec — 2003 LX
YearTrim / engine0–60¼ mileHPDrivetrain
2003LX 2.4L I-48.30 sec16.60 sec138 hpFWD
2001SE V6 2.5L V68.60 sec16.60 sec169 hpFWD
2001SE V6 2.5L V68.70 sec16.60 sec169 hpFWD
2001SE V6 2.5L V69.00 sec16.60 sec169 hpFWD

Service quick specs OEM factory data

Capacities, torques and tune-up values from the factory service manual.

This engine holds 4.5 qt of 20W-40 / 20W-50 / 10W-30 API engine oil. Torque lug nuts to 66-81 ft-lbs. The firing order is 1-2-3-4-5-6. Note the cylinder-head bolts finish on a torque angle (torque-to-yield) — they stretch permanently and should be replaced, not reused, during any head service.

Lubricants & capacities

Automatic Transmission FluidATF
Automatic Transmission Fluid Capacity8.2
Engine CoolantETHYLENE GLYCOL
Engine OilABOVE 32 degrees F
Engine Oil Capacity4.5 qt
Engine OilABOVE 32 degrees F
Engine Oil Capacity5.1 qt
Manual Transmission Fluid75W-90 · GL-4

Engine torques

Camshaft Bearing/Carrier Cap Bolts or Studs14-15 ft-lbs
Camshaft Bearing/Carrier Cap Bolts or Studs10-11 ft-lbs
Crankshaft Pulley and/or Damper Bolts80-94 ft-lbs
Crankshaft Pulley and/or Damper Bolts130-138 ft-lbs
Engine Flywheel Bolts94-101 ft-lbs
Engine Flywheel Bolts53-56 ft-lbs
Intake Manifold to Engine BoltsM8 bolts: 11-14 ft-lbs
Exhaust Manifold to Cylinder Head BoltsM8 nut: 18-22 ft-lbs

Chassis torques

Lug Nuts66-81 ft-lbs
Front Wheel Hub170 ft-lbs
Rear Wheel Hub170 ft-lbs

Ignition

Cylinder Firing Order1-3-4-2
Cylinder Firing Order1-2-3-4-5-6
Curb Idle Speed (No Load)800 rpm
Curb Idle Speed Variance (No Load)100 rpm
Curb Idle Speed (No Load)700 rpm
Curb Idle Speed Variance (No Load)100 rpm
Ignition Coil Primary Resistance.78 ohms
Ignition Coil Secondary Resistance20,000 ohms

Battery & A/C

RefrigerantR134a
Refrigerant Capacity1.50 lbs
Oil GroupPAG
Oil Type46
Oil Capacity5.07 oz
Standard BCI Group Number124R
Standard BCI Cranking Performance600 cca
Standard BCI Group Number124R

Service checks

Injector Primary Resistance13-16 @ 68 degreesF ohms
Engine Compression178 minimum. 14 maximum variation PSI.
Engine Compression149-170 PSI. 14 maximum variation PSI.
Engine Oil Pressure11.6 psi
Engine Oil Pressure RPMIdle rpm
Intake Valve LashHydraulic in
Exhaust Valve LashHydraulic in

Brakes

Brake ApplicationWITH REAR DISC
Torque to Knuckle16-24 ft-lbs / 65-80 ft-lbs
Torque Caliper to Bracket51-63 ft-lbs
Minimum Pad Thickness0.080 in
Minimum Shoe Thickness0.040 in
Brake ApplicationWITH REAR DISC
Rotor Runout Limit0.0012 in
Rotor Nominal Thickness From0.39 in / 1.024 in

Multi-step torque procedures OEM · verified

Connecting Rod (Large End) Bearings — tightening sequence 1 stages
113-16 ft. lbs., Step 2: 90-9413–16 ft. lbs
Connecting Rod (Large End) Bearings — tightening sequence 1 stages
112-14 ft. lbs., Step 2: 90-9412–14 ft. lbs
Cylinder Head — tightening sequence 6 stages

Prep New bolts:

114 ft. lbs.14 ft. lbs
290 degrees90 degrees
3loosen all bolts
414 ft. lbs.14 ft. lbs
590 degrees90 degrees
690 degrees; Original bolts:90 degrees
114 ft. lbs.14 ft. lbs
290 degrees90 degrees
390
Cylinder Head — tightening sequence 3 stages
118 ft. lbs.18 ft. lbs
2turn 58-62 degrees58–62 degrees
3turn 43-47
Main Bearings — tightening sequence 1 stages
118 ft. lbs., Step 2: 90-9418 ft. lbs

Factory maintenance schedule OEM · verified

Normal service, condensed from the factory interval matrix.

Under the factory schedule, replace the engine oil and filter every 7,500 mi; coolant every 24,000 mi. The big-interval services (every 24,000 mi for coolant, and the transmission fluid) are the ones owners most often skip — on a lower-mileage example, assume the original fluids are still in it and check them first.

Every 7,500 miBody Latches, Locks & Hinges (lubricate) · Engine Oil (drain & refill) · Engine Oil Filter (replace) · Tire & Wheel Assembly (rotate) · Transmission Assembly (inspect fluid level)
Every 9,500 miCabin Air Filter (replace)
Every 15,000 miCV Joint Boot (inspect) · Clutch Master Cylinder (inspect fluid level)
Every 24,000 miEngine Coolant System (drain, flush & refill)
Every 30,000 miAccessory Drive Belt (inspect) · Body Fasteners (inspect) · Brake Drum Assembly (inspect) · Brake Line (inspect) · Brake Rotor (inspect) · Engine Air Filter Element (replace)
At 60,000 miTiming Belt (inspect)
Every 60,000 miFuel Filter (replace)
At 62,000 miEngine Coolant System (drain, flush & refill)
At 105,000 miFuel Evaporative Emission Control System Lines (replace) · Timing Belt (replace)

Reliability & federal safety record

Owner-reported issues, recalls, investigations and service bulletins on record with NHTSA — an unfiltered look at what owners actually experience.

Within the early 2001–2006 generation, the 2004 Kia Optima is a clear outlier for owner complaints, logging 225 complaints versus 144 in 2003, 110 in 2002, and 155 or fewer in 2005–2006. That spike did not bring a matching regulatory or manufacturer response: 2004 had only 1 recall, 0 investigations, and 15 TSBs—the lowest TSB count of that period—so the federal record shows elevated reports without a corresponding wave of acknowledged fixes. The leading complaint categories were Latches/Locks/Linkages (58), Structure (21), Electrical System (20), and Air Bags (18), plus 8 crash-related and 3 fire-related complaints, though the data does not specify root causes. Compared with the far larger complaint and recall surge of 2011–2016, 2004 looks minor, but within its own generation it is the most reported year and lacks the recall activity of surrounding model years. That profile implies a higher likelihood of owner-reported problems without documented factory remedies, so any purchase should be paired with a thorough pre-buy inspection targeting those categories. Bottom line: 2004 is not the strongest year of this generation to buy; only consider one with solid maintenance records and a clean inspection, and budget for possible repairs in the latch/lock, structural, electrical, and air-bag systems.

1
Open recalls
NHTSA campaigns
15
Service bulletins
Manufacturer communications
0
ODI investigations
Office of Defects Investigation
225
Owner complaints
8 involved a crash · 3 a fire
Owner complaints by model year NHTSA · this generation & adjacent

Owner complaints filed with NHTSA, by component

All 225 complaints on record, top 8 components.

Latches/Locks/Linkages58
Structure21
Electrical System20
Air Bags18
Suspension11
Electrical System,Latches/Locks/Linkages9
Unknown Or Other8
Structure,Latches/Locks/Linkages8

Source: NHTSA Office of Defects Investigation complaint database.

Recalls NHTSA · verified

Showing 1 of 1 campaigns on record for this vehicle.

09V183000Suspension:FrontReported 27/05/2009

KIA MOTORS CORPORATION (KMC) IS RECALLING 36,538 MODEL YEAR 2001-2004 OPTIMA VEHICLES ORIGINALLY SOLD IN OR CURRENTLY REGISTERED IN THE STATES OF CONNECTICUT, DELAWARE, ILLINOIS, INDIANA, IOWA, MAINE, MARYLAND… Remedy: KMC WILL NOTIFY OWNERS AND DEALERS WILL REPAIR THE VEHICLES FREE OF CHARGE. THE SAFETY RECALL BEGAN ON JUNE 15, 2009. OWNERS MAY CONTACT KIA'S CONSUMER ASSISTANCE CENTER AT…

Technical service bulletins NHTSA · verified

Showing 5 of 15 bulletins on record with NHTSA.

BulletinDateComponentSummary
TSB_BOD055_R12021-09-13StructureTECHNICAL SERVICE BULLETIN: INFORMATION FOR HEADLAMP CONDENSATION AND MOISTURE - This…
PS5392018-03-02Engine And Engine CoolingPITSTOP - ENGINE COMPONENT RE-USE GUIDELINES - In general, parts and components removed…
TSB-GEN085R12017-01-18EquipmentTSB: MANDATORY REPLACEMENT OF LOCKING/SECURITY HARDWARE - By design, certain fasteners…
TSB-GEN0852016-11-04Latches/Locks/LinkagesTSB: MANDATORY REPLACEMENT OF LOCKING/SECURITY HARDWARE - By design, certain fasteners…
PS4432016-04-04Electrical SystemTSB - USE OF AFTERMARKET USB CHARGING CABLES IN USB/12V PORTS - This article provides…

Common OBD-II trouble codes

The most common OBD-II codes for this vehicle's emissions system. These are standardized SAE J2012 definitions, not vehicle-specific fault reports.

P0420
Catalyst system efficiency below threshold — Bank 1
P0300
Random / multiple cylinder misfire detected
P0171
System too lean — Bank 1
P0455
Evaporative emission system leak detected — large leak
P0128
Coolant thermostat below regulating temperature
P0442
Evaporative emission system leak detected — small leak

VIN tools

Decode factory build data for a specific vehicle by VIN.

VIN
Decode a VIN to confirm the transmission and build data for a specific Optima. OEM
Build data
Plant, GVWR class, engine and body data for any 17-character VIN.
Recalls
Check open recall campaigns against a specific vehicle by VIN.

Vehicles with shared specs

Find every vehicle that shares this one's battery, bulbs, oil capacity, platform or parts.

Reference guides

Cross-vehicle references for the kinds of data on this page.

Frequently asked

How much oil does the 2004 Optima take?

4.5 qt of ABOVE 32 degrees F: 20W-40 OR 20W-50 API SM, ABOVE -10 degrees F: 10W-30, 10W-40 OR 10W-50 API SM, BELOW 100 degrees F: 5W-30 OR 5W-40 API SM, per the factory manual.

Does the 2004 Optima have open recalls?

NHTSA lists 1 recall campaign(s) for this model year. Check your specific vehicle by VIN.