If the anti-freeze was not replaced at proper intervals, which depends on the brand most are a year to two years, that would cause it to not have the anti-freeze capabilities necassary to prevent things like a blown head gasket from happening. The mileage is not a factor it is how old the anti-freeze is. However, high milage can shorten the service life of anti-freeze some, but more of its lubrication qualities get lost as opposed to it anti-freezing capability.
Sometimes head gaskets do go for other reasons.
The test they are performaing is a leak down test. This will see if the sytem is holding pressure for as long as it is suppose to anmd it will puch fluid in the area where it is leaking. This will help to dtermine if it is just a head gasket or if there is possibly a crack in the head or block.
The decision to junk it is up to you, the mileage is rather high though and you are going to at least need a head gasket, even with a good fix or used motor, the car won't make it past 200,000 miles in most case. I have seen some make 300,000, but only if they are really amintained. Then you have to think of things like replacing suspension components and body bushings if you want to get that kind of mileage out of it.
I hope this information helps.
Friday, November 11th, 2011 AT 6:24 PM