You know just lucky I guess. I am at a little over 289,000 now and just drove it across the country last week.
I am a fanatic about oil changes and use Mobil 1. I don't drive like a maniac and try and keep up on maintenance with regular coolant changes, filters, spark plugs, etc. I am believer in using a vehicle and had different mechanics over the years tell me that all engines like to be run on a regular basis.
My primary engine issues over the years have been head gaskets replaced once, two Alternators and a fuel pump. Other than that just the normal filters, lube etc.
Keeping my fingers crossed...