Thanks for the info. Wonder why he retired. Maybe they saw something they didn't like, but that was non-fatal (some kind of slow leak) ? Can't imagine they'd just give up on the whole race if all was well. Awaiting the team race-day press release.
Edit : Just after I posted, the press release appeared
. "Unfortunately, on the reconnaissance lap prior to the race, we could see that something was not right on Hartley's car. We tried to fix it and still sent him out, but it was clear there was a problem and we had to retire him. The problem has now been traced to a loose connector on the PU side."