What is the average engine life of a Subaru?

Answer 1

I have a 2004 Outback , oil change every 3,000 miles lasted 6 years / 78,000 miles before needing a new engine. There is an inherent design flaw in Subaru engines. They use aluminum heads with valve guide inserts. With the expansion and contraction of the head caused by heating and cooling , the valve guides work loose and eventually cause the piston to hit the head. This in turn causes stress on the big end bearings causing failure.

The combination of these events means that a new engine is required.

The use of aluminum heads in the Subaru engines have reliability concerns due to the shifting of the valve guides, causing the pistons to hit the valves and cause catastrophic engine failure. This is caused by the fact that the aluminum head expands and contract at a different rate to the valve guide insert causing the valve guide to eventually become loose.

Due to manufacturer quality issues certain engines are more prone to dropping a valve seat during operaiton. This usually occurs when the engine is hot, from heat distortion, due to Aluminum's ability to expand 5 times the rate of steel. The aluminum material that holds the valve guide will expand and hold the valve guide with less pressure. As the valve guide becomes less restrained, stress from regular operation can work it lose completely, disbanding it from the aluminum head. Once this occurs the movement of the valve will usually break the valve guide insert into pieces, effectively eliminating any compression in the corresponding cylinder, and creating a lot of damage from the loose metal debris inside the combustion chamber.

The old subaru designs are probably ok, just the new ones with aluminum heads are the ones to avoid. This is also reflected in consumer reports as major engine failure in cars 5-6 years old or older

Subaru engines will last several hundred thousand miles as long as you take care of it. ( Change the oil regularly. REGULARLY!!! as with any other motor.) Mine lasted for 199,640 miles and ran great until someone totaled the car for me!!

i have a 1994 subaru impreza it has 225,675 miles and it is still running great!