The head gasket has a high failure rate due to cooling system problems. Subaru is aware of the problem and has extended the warranty to 8 years/100k miles on many vehicles.
Resources for the Repair and Maintenance of your 2003 Subaru Impreza Outback
2003 Subaru Impreza Outback
2003 Subaru Impreza Outback Problems
Front engine oil leaks can develop from the camshaft seal and the crankshaft front seal. If one or more seals require replacement, it may be wise to consider replacing the timing belt as well. These seals are commonly inspected and replaced as needed as part of a timing belt service.
The leak may develop from the oil pump seal. Our technicians prefer to use thread locker when replacing the seal to prevent the bolts from becoming loose again.
The Check Engine Light may illuminate because of a failed knock sensor. Although the sensor often tests okay, it can fail intermittently, while the vehicle is being driven.
Sometimes the Check Engine Light illuminates because the computer detects misfires. Subaru released an improved spark plug wire set to solve the problem. The ignition coil should also be inspected for carbon tracks or short circuits between the contacts
2003 Subaru Impreza Outback Recalls (Recent)
Summary: SUBARU IS RECALLING CERTAIN MODEL YEAR 2002 AND 2003 IMPREZA WRX VEHICLES ORIGINALLY SOLD IN OR CURRENTLY REGISTERED IN THE STATES OF SOUTH DAKOTA, NEBRASKA, NORTH DAKOTA, MINNESOTA, IDAHO, IOWA, MONTANA, COLORADO, WISCONSIN, NEW YORK, WYOMING, MICHIGAN, ALASKA, NEW HAMPSHIRE, VERMONT, AND MAINE. DURING COLD STARTS, TYPICALLY UNDER EXTREMELY COLD TEMPERATURES, FUEL LEAKS IN THE FUEL DELIVERY LINE COULD OCCUR WHERE THE LINE CONNECTS WITH A RUBBER HOSE.Learn more »