what does it mean if the only problem is that the car is low on antifreeze? on 2003 Subaru Legacy

I brought my car on for it's 60,000 mile tune up and my mechanic noticed that the antifreeze was low and says i need a new head gasket. there is no overheating or any other issues at all except it was low on antifreeze. what is your advice?

Asked by for the 2003 Subaru Legacy
get a second opinion.
1 more answer
A second opinion is a good idea, but your mechanic is probably trustworthy and deserves to get the repair. These all develop head gasket seeps at some point. At my shop we recommend that since the engine has to come out anyway for the gaskets, replace the plastic oil baffle at the rear of the engine, all the timing components, and have the valvs adjusted by a machine shop. It's expensive to do it all together, but much more expensive to do them all seperately as the inevitable needs arise.