I had an unusual incident with my 1983 Mondial QV. I would appreciate comments from anyone who has direct experience with timing belt slippage or breakage. I have reviewed all of the available Youtube videos. First, I will describe the incident. The car had been running fine, but was being stored in an unheated building for the winter. I needed to move the car. It was about 20 degrees Fahrenheit. The car started right up, but I immediately heard a "tinkling" sound and recognized that it was only running on four cylinders. I shut it down as quickly as possible. I suspected that one of the timing belts had broken. Fearing the worst (broken belt, bent valves, big repair bill), I removed the timing belt covers. Both camshaft timing belts were intact. But, the intake camshaft on the rear cylinder bank (1-4) was out of time by one tooth. So, it seemed that this belt had slipped one tooth on the intake camshaft. The strange thing is that the camshaft was ADVANCED one tooth, not retarded. It is not clear to me how this could have happened. Subsequent static leakdown tests have shown no indication of bent valves. My questions are: Has anyone else encountered a camshaft that was advanced after belt slippage rather than retarded? Any thoughts on how this might happen? Can I be confident that I have no internal damage based on the results of the leakdown tests and the fact that the camshaft had only been off one tooth? I don't want to pull the head since there seems to be no valve damage. Has anyone encountered actual breakage of a timing belt as opposed to slippage? It would seem that releasing the cam belt tensioners would be a good intermediate maintenance step to allow them to take up any wear that has occurred over time. Does any one actually do this? And finally, I would be interested in any suggestions on what the "tinkling" sound I heard might have been since it does not appear that there was any contact between the pistons and valves. Thanks in advance for your constructive feedback.