<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I think it would be incredibly difficult to get an MGB <i>in good condition</i> to boil over.<div><br></div><div>I've driven my car in 110F temps with an 8lb radiator cap, I've sat in traffic for an hour at 105F. </div><div><br></div><div>Back in the summer of 1998, one of the clubs had a track day at Summit Point, in West Va. My father and I shared my MG for the day. The starter jammed that morning, and nothing we could do in the pits could un-jam it -- so the car was push-started once in the morning, and once after lunch; the rest of the day was alternating sessions of hot laps and autocross (with waiting-in-line time for the autocross, as well). It was over 90F that day, and we hammered the car for hours. At the end of the day, I drove it 300 miles home. It didn't boil over.</div><div><br></div><div>That said, in all this thrashing around, the temps did rise. It comes off the thermostat-defined temperature (180F) at about 80F ambient temperature, and I've been thinking about ways to keep it cooler. But boiling over? Not yet.</div><div><br></div><div>Matt</div></body></html>