Got an intermittent overheating issue with my XTE and starting to get a bit frustrated. Started about a month ago (just out of warranty!). After some "vigorous" driving, which caused no problems - engine temp normal throughout - I stopped for 5 minutes with the engine off then set off again. Within half a mile the engine temp was in the red. Same again about three weeks later. Yesterday I took my daughter and her friends to a gig in Manchester. Spent 2 hours in crawling traffic on the M6 then around 50 miles at a little over the speed limit as we were late. No problems. Pulled into M61 services, stopped for 10 minutes to get food then set off again - within half a mile, temp in the red. Coming home, sat at on the M6 and a dual carriageway for around 90 miles, stopped to drop off one friend, within half a mile, temp in the red. No leaks obvious, coolant seems to be holding its level more or less, had a compression test done last week which came back at 150, 150, 150 and 155 over a sustained period, and cold and warm pressure tests which held pressure levels. Anyone got any ideas about possible causes or what I should do next? My mechanic has owned Imprezas for years but is also scrathching his head. Thanks in advance.