The 2004 Subaru Forester. It's a rugged, reliable, and versatile vehicle that has earned a loyal following over the years. Known for its symmetrical all-wheel-drive, ample cargo space, and comfortable ride, it's a great choice for families, adventurers, and anyone who needs a practical and capable vehicle. However, like any car nearing its third decade, the 2004 Forester has its share of common problems that potential buyers and current owners should be aware of.

So, What's Been Bugging Forester Owners Lately? The Usual Suspects

Let’s dive into the most frequent issues owners have reported with their 2004 Foresters. Knowing these quirks can help you anticipate potential problems, budget for repairs, and keep your Forester running smoothly for years to come.

Head Gasket Woes: The Subaru Achilles' Heel

(The dreaded head gasket issue is perhaps the most notorious problem associated with the 2004 Subaru Forester, particularly those equipped with the 2.5-liter engine.) Subaru engines, especially those from this era, used a single-layer head gasket design that was prone to failure.

  • What Happens? The head gasket seals the cylinder head to the engine block. When it fails, coolant and oil can leak internally (mixing in the engine) or externally (dripping onto the ground).
  • Symptoms: Overheating, coolant loss, white smoke from the exhaust (indicating coolant burning), milky-looking oil (indicating coolant mixing with oil), and bubbling in the coolant overflow reservoir.
  • The Fix: Replacing the head gaskets is the only permanent solution. This is a relatively labor-intensive job, so expect a significant repair bill. Many mechanics recommend using a multi-layer steel (MLS) head gasket as a replacement. These are more durable and less prone to failure than the original gaskets.

Oil Leaks: A Constant Companion

Subaru engines are known for developing oil leaks as they age. While not always catastrophic, they can lead to low oil levels and potential engine damage if left unattended.

  • Common Leak Locations: Valve cover gaskets, oil pan gasket, rear main seal, and the front crankshaft seal are all common culprits.
  • Symptoms: Visible oil leaks under the car, oil spots on the driveway, and a burning oil smell.
  • The Fix: Replacing the leaking gaskets or seals is the solution. Start with the easiest and most accessible leaks, like the valve cover gaskets, before tackling the more challenging ones like the rear main seal. Regularly checking your oil level is crucial to prevent engine damage.

Catalytic Converter Failure: Emissions Troubles

Catalytic converters are essential for reducing harmful emissions. They can fail due to age, overheating, or contamination from oil leaks.

  • Symptoms: Check engine light (often with codes P0420 or P0421), decreased fuel economy, and a sulfur-like smell from the exhaust.
  • The Fix: Replacing the catalytic converter is usually necessary. However, it's crucial to diagnose and address the underlying cause of the failure (e.g., oil leaks) to prevent the new converter from failing prematurely.

Oxygen Sensor Issues: Keeping Emissions in Check

Oxygen sensors monitor the amount of oxygen in the exhaust stream and provide feedback to the engine control unit (ECU). Faulty oxygen sensors can negatively affect fuel economy and emissions.

  • Symptoms: Check engine light (often with codes related to oxygen sensor malfunction), poor fuel economy, and rough idling.
  • The Fix: Replacing the faulty oxygen sensor(s) is the solution. There are typically two oxygen sensors: one upstream (before the catalytic converter) and one downstream (after the catalytic converter).

Suspension Sag: Feeling a Little Low?

Over time, the suspension components of the 2004 Forester can wear out, leading to a sagging ride height, especially in the rear.

  • Common Causes: Worn-out struts, springs, and bushings.
  • Symptoms: Reduced ground clearance, a bouncy ride, and uneven tire wear.
  • The Fix: Replacing the worn suspension components is the solution. Consider upgrading to aftermarket struts and springs for improved handling and durability.

Rust: The Enemy of All Cars

Rust is a common problem for older vehicles, especially in areas with harsh winters and road salt.

  • Common Rust Locations: Wheel wells, rocker panels, undercarriage, and around the windshield.
  • Symptoms: Visible rust, bubbling paint, and structural damage.
  • The Fix: Addressing rust early is crucial to prevent it from spreading. Sanding, treating, and repainting affected areas can help. For severe rust, welding in new metal panels may be necessary. Applying rustproofing treatments can help prevent future rust.

Automatic Transmission Troubles: Shifting Problems

While generally reliable, the automatic transmission in the 2004 Forester can experience issues as it ages.

  • Symptoms: Slipping gears, harsh shifting, delayed engagement, and unusual noises.
  • Common Causes: Low transmission fluid, worn-out clutches, and a failing torque converter.
  • The Fix: Start by checking the transmission fluid level and condition. If the fluid is low or dirty, a fluid change may help. For more serious problems, a transmission rebuild or replacement may be necessary.

Power Window and Door Lock Issues: Convenience Gone Wrong

The power windows and door locks in the 2004 Forester can sometimes malfunction due to worn-out motors, switches, or wiring.

  • Symptoms: Windows that don't go up or down, door locks that don't work, or intermittent operation.
  • The Fix: Replacing the faulty motor, switch, or wiring is the solution. Start by checking the fuses and wiring connections.

Air Conditioning Problems: Staying Cool

The air conditioning system in the 2004 Forester can experience issues such as leaks, compressor failure, and clogged condensers.

  • Symptoms: Weak or no cold air, unusual noises from the compressor, and leaks in the system.
  • The Fix: Diagnosing and repairing the AC system can be complex. Common repairs include recharging the refrigerant, replacing the compressor, condenser, or other components, and repairing leaks.

Electrical Gremlins: The Unpredictable Issues

Older cars can sometimes develop electrical problems that are difficult to diagnose.

  • Symptoms: Intermittent issues with lights, sensors, or other electrical components.
  • Common Causes: Corroded wiring, loose connections, and failing sensors.
  • The Fix: Tracking down electrical problems can be time-consuming. Start by checking the fuses, wiring connections, and grounds. A multimeter can be helpful for testing circuits.

Keeping Your Forester Healthy: Preventative Maintenance is Key

Regular maintenance is crucial for keeping your 2004 Subaru Forester running smoothly and preventing major problems. Here are some key maintenance items to keep in mind:

  • Regular Oil Changes: Change the oil and filter every 3,000-5,000 miles, depending on your driving conditions. Use a high-quality synthetic oil.
  • Coolant Flushes: Flush the coolant system every 30,000 miles to prevent corrosion and overheating.
  • Transmission Fluid Changes: Change the transmission fluid every 30,000-60,000 miles, depending on your driving conditions.
  • Brake Inspections: Inspect the brakes regularly and replace worn pads, rotors, and calipers as needed.
  • Timing Belt Replacement: If the timing belt hasn't been replaced recently, it's crucial to do so. A broken timing belt can cause catastrophic engine damage. The recommended interval is typically every 105,000 miles or 105 months (whichever comes first).
  • Tire Rotations: Rotate the tires every 6,000-8,000 miles to ensure even wear.
  • Regular Inspections: Have a mechanic inspect your Forester regularly for any potential problems.

Finding a Good Mechanic: Someone You Can Trust

Finding a skilled and trustworthy mechanic is essential for maintaining your 2004 Subaru Forester. Look for a mechanic who specializes in Subaru vehicles or has extensive experience working on them. Ask for recommendations from other Subaru owners and check online reviews.

DIY vs. Professional Repair: Knowing Your Limits

Some repairs on the 2004 Subaru Forester can be done by DIY mechanics, while others are best left to professionals. Simple tasks like changing the oil, replacing the air filter, and replacing the spark plugs can often be done at home. However, more complex repairs like head gasket replacement, transmission work, and electrical troubleshooting are best left to professionals.

Frequently Asked Questions

  • Why is my 2004 Forester overheating? Overheating is often caused by a faulty head gasket, low coolant, a clogged radiator, or a malfunctioning thermostat. Check these components and address any issues.
  • What does the check engine light mean? The check engine light can indicate a wide range of problems. Have the code read by a mechanic to determine the specific issue.
  • How often should I change the oil? Change the oil every 3,000-5,000 miles, depending on your driving conditions and the type of oil you use.
  • Is the head gasket issue a guaranteed problem? While common, not all 2004 Foresters will experience head gasket failure. Regular maintenance and careful monitoring can help prevent or delay the issue.
  • Can I use regular gas in my 2004 Forester? The 2004 Forester is designed to run on regular unleaded gasoline. Using premium fuel is not necessary and will not improve performance.

The Bottom Line

The 2004 Subaru Forester is a reliable and capable vehicle, but like any older car, it has its share of potential problems. Staying informed about these issues and performing regular maintenance can help you keep your Forester running smoothly for many years to come. Don't neglect regular maintenance and address issues early to prevent bigger problems from developing.