We had 135,000 and it was running beautifully, no problems at all. I was actually wondering why so many people preferred the DOHC Zetec over this engine. My other Focus is a 2000 with the Zetec and 105,000....although it runs good I can't get it to idle smoothly. The 2003 with the SOHC sometimes you would have to check to see if it was running it was so smooth. No warning at all, just dropped the seat and it was done. Although, my understanding is that it has to do with running temp, and it was 107 in the shade at the time and I was running the AC...go figure.
In retrospect, had I know about the head issue I would have changed it out immediately. Which is a much easier process than what I have now.....so if I were you.....I would get that head changed out now.....it is a ticking time bomb!....not a question of "IF" but a question of "WHEN"
Frustrated Shade Tree Mechanic