The Subaru EZ30 engine is a well-rounded mid-size powerplant with plenty of power and torque for various applications. It features a cast iron block, cylinder heads for durability, forged steel connecting rods, and low-friction piston rings. The EZ30 also has several notable technological advancements, such as variable intake and exhaust valve timing, roller-finger followers for the valves, and an electronically controlled throttle body. All of these features combine to make the EZ30 a very capable engine that can deliver good performance in a wide range of conditions.
The Subaru EZ30 engine was first introduced in the 1999 Subaru Legacy. It is a 3.0-liter horizontally opposed (or “boxer”) six-cylinder engine with an output of 245 horsepower and 209 lb-ft of torque. It was the first engine in a Subaru to use the “EZ” nomenclature, and it quickly became one of the most popular engines in the company’s lineup.
This engine was used in various Subaru models over the years, including the Outback, Forester, and Baja. It was also used in the Saab 9-2X. The EZ30 engine was discontinued in 2009 and replaced by the newer FB series engines.
Despite its age, the EZ30 engine is still popular with many Subaru enthusiasts. It’s known for its reliability and its wide variety of aftermarket parts. If you’re looking for an engine to power your Subaru, the EZ30 is a great option.
Subaru EZ30 Engine Specs
The Subaru EZ30 engine was first introduced in 1999 to replace the aging EG33 engine. The engine was created completely from scratch and used an aluminum flat-6 cylinder block with cast-iron sleeves, 2 mm thick, and a cylinder block deck height of 202 mm.
The engine has a piston stroke of 80 mm, a connecting rods length of 131.5 mm, and a piston compression height of 30.3 mm. The EZ30 engine has a compression ratio of 10.7 and a capacity of 3 liters. The engine has two aluminum DOHC heads with two camshafts and four valves per cylinder. The camshafts are put in action using two timing chains.
The EZ30 engine applies an aluminum variable-length intake manifold, and its switching happens at 3,600 rpm. The EZ30 engine produces 220 horsepower at 6,000 rpm and a torque of 289 Nm at 4,400 rpm. The EZ30R engine, which is a newer version of the EZ30, has a power output of 245 horsepower at 6,600 rpm and torque of 297 Nm at 4,200 rpm.
The EZ30R engine has an electronic throttle body with a diameter of 76 mm, a plastic intake manifold, and an MAF sensor. The EZ30 engine uses a timing chain rather than a timing belt.
The engine was used in several Subaru models, including the Outback, Legacy, and Baja. The engine was mated to a four-speed automatic transmission.
|Manufacturer||Gunma Oizumi Plant|
|Also called||Subaru EZ30|
|Cylinder block alloy||Aluminum|
4 valves per cylinder
|Piston stroke, mm (inch)||80 (3.15)|
|Cylinder bore, mm (inch)||89.2 (3.51)|
|Displacement||2999 cc (183 cu in)|
|Power output||164 kW (220 HP) at 6,000 rpm|
183 kW (245 HP) at 6,600 rpm
|Torque output||289 Nm (213 lb·ft) at 4,400 rpm|
297 Nm (219 lb·ft) at 4,200 rpm
|HP per liter||73.3|
|Weight, kg (lbs)||180 (397)|
|Fuel consumption, L/100 km (mpg)|
|Oil consumption, L/1000 km|
(qt. per miles)
|up to 1.0|
(1 qt. per 600 miles)
|Recommended engine oil||0W-30, 5W-30, 5W-40, 10W-30, 10W-40|
|Oil capacity||5.7 quarts|
|Oil change interval, km (miles)||5,000-10,000 (3,000-6,000)|
|Normal engine operating temperature, °C (F)||90 (194)|
The EZ30 engine was discontinued in 2009 and replaced by the 3.6L DOHC flat-six engine.
Subaru EZ30 Weight
The weight of the Subaru EZ30 engine is approximately 170 kg or 375 lbs. However, the EZ30R engine, which is a newer version of the EZ30, weighs 180 kg or 397 lbs. It is important to note that the weight of an engine can vary depending on the specific model and configuration.
Subaru EZ30 Engine Horsepower
The EZ30 engine generates 220 horsepower at 6,000 rpm and a torque of 289 Nm at 4,400 rpm. On the other hand, the EZ30R engine, which is an updated version of the EZ30, produces a power output of 245 horsepower at 6,600 rpm and a torque of 297 Nm at 4,200 rpm.
This engine is a great choice for those looking for more horsepower and torque than other Subaru engines.
Subaru EZ30 Timing Belt or Chain?
The Subaru EZ30 engine, which is a 3.0L H6 engine, uses a timing chain rather than a timing belt. The timing chain in the EZ30 engine does not normally need to be replaced during the vehicle’s life, unlike timing belts, which have a finite lifespan and require periodic replacement.
Timing chains typically last for at least 200,000 miles, and many are still good at 300,000 miles. Therefore, the timing chain in the Subaru EZ30 engine should last the life of the engine without replacement.
If you own a 2004 H6.30 Outback Wagon, you do not need to consider replacing the timing chain, as it does not normally need to be changed during the vehicle’s life.
Engine Firing Order
The firing order of the Subaru EZ30 engine is 1-6-3-2-5-4. This firing order specifies the sequence in which the engine’s cylinders receive a spark from the distributor. It is essential for properly functioning the engine’s ignition system and timing its internal combustion process.
If you are looking for a reliable engine with low emissions, the Subaru EZ30 engine is a great option.
Subaru EZ30 Engine Oil Capacity
The Subaru EZ30 engine requires 5.7 quarts of 0W-30 or 5W-30 oil with a filter replacement.
Read Also: Subaru Outback oil capacity
Synthetic oil is recommended for this engine because it offers better protection against heat and wear. The EZ30 engine is a high-performance engine; therefore, synthetic oil is necessary to protect the engine from wear and tear.
The EZ30 engine is a reliable engine that is known for its durability. This engine is a popular choice among Subaru enthusiasts who are looking for an upgrade from the 2.5-liter engine.
What Cars Have A Subaru EZ30 Engine?
This engine was used in the following vehicles:
- 1999-2009 Subaru Outback
- 2000-2009 Subaru Legacy
- 2003-2008 Subaru Forester
Durability and Reliability
The Subaru EZ30 engine is generally considered reliable and durable, with a good lifespan of 180,000 miles. While there are some minor issues associated with the design, overall, the engine is praised for its longevity and reliability
According to Subaru owners, the EZ30 engine is associated with above-average reliability and durability, with a good milestone for its upward lifespan of 180,000 miles.
However, a few minor problems are commonly associated with the EZ30 design, such as potential timing cover and valve cover leaks. Also, there is an occasional timing chain tensioner failure, which can cause a knocking sound. Despite these issues, the EZ30 engine is often seen, especially in older Outback models, and is generally regarded as a reliable powerplant.
Engine Problems And Solutions
The Subaru EZ30 engine is widely recognized for its longevity and reliability. Many owners have praised its reliability. However, there are some minor issues associated with the EZ30 design, such as potential timing cover and valve cover leaks. The timing chain tensioner may occasionally fail, resulting in a knocking sound.
The H6 engine is also reliable, but age and mileage can cause problems. To keep the engine in good condition, all worn parts such as seals, belts, and fluids must be replaced.
The H6 is more robust than the 2.5, which often has head gasket problems at around 115k miles. All EZ30 2001+ Subaru H6 engines have timing chains and do not require maintenance.
In summary, the Subaru EZ30 engine is generally considered reliable, but some minor issues are associated with the design.
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