Workshop Manuals Factory service & repair Subaru

Subaru common faults and how to fix them

Faults that are well known on Subaru models we hold manuals for: what the owner notices, what causes it, and the pages in our manuals that cover the repair.

Subaru head gasket: 2.5 coolant leaks and the Subaru coolant conditioner (1999–2002)

Symptoms

Small external coolant leaks at the joint between the cylinder heads and the block, often first seen as dried coolant crust on the head gasket edge or a slowly falling coolant level.

Cause

Subaru campaign WWP-99 covers the 2000–2002 Legacy and Outback, and the 1999–2002 Impreza and Forester. Subaru of America found that these cars may develop small external coolant leaks at the cylinder head gaskets over time, which it put down to the normal expansion and contraction of the engine as it heats and cools.

Fix

The campaign adds Subaru Cooling System Conditioner to the coolant, both to prevent the leaks and to seal small existing ones. The Subaru coolant conditioner bulletin explains how much to add. If a Subaru head gasket is leaking heavily, or the engine has overheated, the gaskets have to be replaced, which means taking the heads off. Refill and bleed the cooling system as the manual describes.

Repair instructions on this site

Sources: Subaru campaign WWP-99 (engine cooling system conditioner).

Subaru wheel bearing: whining or squealing from the rear or front

Symptoms

A whine from the rear wheels that rises with road speed, or a squeak or squeal from the left front wheel area. The car otherwise drives normally.

Cause

Subaru bulletins cover three cases. On the 2005–2006 Legacy and Outback, a rear wheel bearing can develop a whining noise; Subaru extended the warranty and replaced the bearing. On the 2005–2007 Legacy and Outback, a left front squeal can come from the bearing seal lip sticking to the housing flange, which wears smooth over time. For the 1998–2003 Forester, 1993–2003 Impreza and 1990–1999 Legacy, Subaru revised the rear bearing replacement procedure and the bearing design to make them last longer.

Fix

Raise the car and check each wheel for play and roughness to find the noisy bearing. For a 2005–2006 Legacy or Outback rear bearing, follow the Subaru wheel bearing bulletin. For a left front squeal on the 2005–2007 cars, the front bearing squeal bulletin explains the seal. On older Foresters, Imprezas and Legacys, use the revised rear bearing procedure.

Repair instructions on this site

Sources: Subaru service bulletins 03-58-08 and 03-62-09; Subaru bulletin on revised rear wheel bearing installation.

Subaru oil leak: oil flow control valve cover recall (2004 Forester)

Symptoms

An oil leak from around the cover on the engine's oil flow control valve, sometimes with oil collecting on the engine below it.

Cause

NHTSA recall 04V473000 (Subaru recall WWU-05) covers certain Subaru cars and SUVs, including the 2004 Forester 2.5 in our manuals. The bolts holding the cover on the engine oil flow control valve may not have been tightened enough, so oil can leak from around the cover gasket. If the oil reaches hot parts of the engine, it could start a fire.

Fix

Check with a Subaru dealer that the recall has been carried out; the remedy inspects and retightens the oil flow control valve cover bolts. If oil is leaking, clean the area and fit a new gasket if needed, tightening the bolts to the figure in the manual. The Subaru oil leak recall notice gives the details.

Repair instructions on this site

Sources: NHTSA recall 04V473000 (Subaru recall WWU-05).

Repair instructions for every Subaru model: Subaru workshop manuals