What causes the coolant in the tank to get foamy and bubble? on 1999 Subaru Legacy Outback

I had the radiator replaced several times, recently new timing belt, new water pump and tune up. Headed out for Alaska and it over heated...Another new radiator and another overheating...Now I am told a new head gasket will take care of the problem. Could it be something more?

3 answers
you could have a blown head gasket
Subaru has had a lot of problems with the head gaskets on the 2.5l. Make sure you have a shop that is experienced with Subaru's do the work.
very common for head gasket leaks on these , seek diag and est