'99 Subaru Outback Overheating

The 1999 2.5L DOHC engine is known for head gasket problems. If I remember right there was some sort of recall, where you can go in to a Subaru dealership and have them treat your engine with some sort of sealant. Worth asking. There is also a product you can buy that worked for me when I had a minor head (gasket) leak. The process involves draining all your coolant, then adding pure watter and the sealant, running it too temperature, letting it cool, then flushing the system and refilling with coolant mix. But if your leak is bad enough that you are getting quite a bit of oil sludge in your coolant, it may be too late. Head gaskets, and machine/pressure-test of the heads may be your only route. Unless you want to get tricky and pop a WRX engine in there! :) Peace, Stephen

theres no recalls on that model, subaru has a sealant that you add to the coolant to slow down the leaking. other than that you will need to change the headgaskets.