Not been on for ages been going great no problems till last night went out for day 300 miles in total 10 miles from home engine just stalls at 20mph all electrics still work. When i turn the key to start i get sort of clunk noise we had no oil lights or warning lights temp was normal called AA they can't get reading from comp on car he thinks engine seized can it just seize with no warning when we opened up bonnet to look not overly hot no burning smell still got all oil and water battery good anyone got any clues any help would be great thanks