Also known as: ez30, ez30r, ez36, subaru flat-six, h6, ez30d, ez36d
Subaru's flat-six — in the Legacy, Outback and Tribeca.
It is the smooth, unstressed alternative to the turbocharged fours, and its character follows: naturally aspirated, chain-driven, and notably free of the head-gasket reputation that attaches to the four-cylinder EJ.
That last point is worth making explicitly, because a great deal of what is written about Subaru engines is about EJ head gaskets — and it does not apply to this engine. The six uses a different block, different head sealing and a chain rather than a belt.
Its own recurring items are oil-related. The valve-cover gaskets leak onto the exhaust and produce a burning smell that alarms owners more than it should; and on the EZ30R and EZ36 the variable valve lift system depends on oil pressure and cleanliness, so a rough idle or a flat top end on a neglected engine is an oil question before it is a mechanical one.
A flat-six is expensive to work on for the same reason it is smooth: the cylinder heads face outward into the wheel arches, and almost nothing is reachable from above.
Cars fitted with this engine
8 generations, across 1 make. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
Information, not instruction
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