Looking for any ideas on this prior to taking it to dealer. Have a '97 Legacy GT (2.5 engine with manual trans.). 142k miles on the vehicle, mostly highway driving. Noticed oil in the coolant tank this weekend. No idiot lights or CEL on. All routine maintenance done as scheduled and oil change interval is 5k miles. Engines been running fine but obviously this isn't right. I've heard this could be a head gasket issue (I believe dealer replaced head gasket on one side back around 120k but I need to dig up the paperwork to confirm). Anything I should check prior to taking it to the dealer? What other possibilities for this?
Thanks,
Jer