Three problems related to radiator have been reported for the 1998 Subaru Outback. The most recently reported issues are listed below.
We bought a 1998 Subaru Outback in 2004. At approximately 110,000 miles, we experienced a catastrophic overheating of the engine due to a faulty head gasket. The overheating caused approximately $3,000 worth of damage to the car. The head gasket, radiator, thermostat, water pump, oxygen sensors and (2) catalytic converters all had to be replaced. We have since learned that this is a common problem for Subarus of this vintage. There are hundreds of anecdotal reports of people having this exact problem on the internet, and our mechanic tells us he fixes at least one of these problems per week at his shop. Clearly, this is a defective product.
Legacy Outback with 2. 5 l engine began to overheat with coolant boiling over into resevoir. The car was taken to repair shop. They replaced thermostat, tested for hydrocarbons in system, pressured tested cap and system and flushed radiator. Car still overheated and was returned to repair shop and tested for hydrocarbons in the antifreeze with negative results. No problem was identified. Engine continued to overheat and was taken into repair shop while the pointer was off the top of the temperature gauge. This time hydrocarbons were identified in the coolant and problem was identified as a blown gasket. Manager reported that the week before another Subaru owner had the same problem with same difficulty in identifying the cause. Repairs cost $1,400. Had a similiar report for another Subaru owner but work was done with pressure on dealer after initial refusal.
1998 Subaru Outback showed signs of overheating as temperature gauge rose up past the usual midline and cold air inside car from air conditioner suddenly got warmer. I pulled over and coolant was over flowing from overflow reservoir through the cap. I drove with the heater on full power and made it to a repair facility and remove the thermostat which had seized. Replaced the thermostat and radiator cap ($30) and everything was fine until four months later (March 2004) when car showed signs of over heating again (rise in inside air conditioned air temperature from cold to warm). Took car to rallysport engineering in costa mesa, CA and mechanic could not find symptoms of head gasket failure although this is what he thought it was. He added stop leak, new thermostat, and new coolant ($150 parts/labor) and the problem was resolved although the temperature gauge reading was a little higher than it was when using original equipment (prior to November). Now, July 2004, car has almost overheated again. I took the car to south coast Subaru in costa mesa, CA and they stated that it was a head gasket failure and that they could smell the exhaust fumes through the overflow reservoir. The estimate to fix the repair will be $1500 parts and labor.