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Subaru 2.5 liter engine

Time:2018-01-12 20:39Turbochargers information Click:

Engine Subaru Liter


More about diagnosing problems

Phase 1 engines:

Phase 1 engines typically experience an "internal" head gasket failure if failure happens. This is hard for a lot of mechanics to diagnose, is difficult to reliably duplicate, and often has resulted in the owners throwing money and parts at the problem. New thermostats, flushing coolant, new water pumps and radiators are examples which do not fix the problem if it is indeed head gasket failure. If the engine overheats too many times or too severely, it can result in warped heads and the need for a new engine. As of this date Subaru has never acknowledged the existence of any problem, and are unlikely to do so. They have redesigned the head gaskets and most people that have had the new gaskets properly installed have had good success. The "coolant conditioner" described in WWP-99 DOES NOT fix this internal leak, nor does it give you an extended warranty against head gasket failure. Headgasket replacement is your only option besides engine replacement.

Common symptoms:
Overheating, often when slowing or stopped after extended high load driving. The overheating can be seemingly random and sporadic.
Bubbles in coolant overflow reservoir, immediately after running.
Sludgy residue in coolant overflow tank.
Hydrocarbons in coolant overflow tank, this is tested by a mechanic with specialized equipment and is not evident visually.

Phase 2 engines:

* Phase 2 engines are SOHC (Single Overhead Cam), were used from 1999 or 2000 to present depending on model, and typically experience an "external" head gasket leakage if it happens. This problem, while pretty widespread, does not seem to be as damaging in nature to the engine. It has been acknowledged by Subaru in the form of a "Service Campaign" #WWP-99 which applies to certain '99 to '02 cars. It involves adding a "Coolant Conditioner" to the coolant and if this is done the owner's head gaskets are covered against external coolant leaks for 8 years or 100K miles.

Common symptoms:
"Sweet" smell after operating engine and then stopping.
External fluid leakage (green) visible on engine or below car.
Slowly dropping coolant level due to leakage.

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