I recently bought a 87 420 SEL with 142K miles on it. Service records were good and I saw that the timing chain was replaced at 110K. About two weeks ago on cold start up I heard a severe rattling when I started the engine. It seemed to be coming from the passenger side valve cover. I turned the car off and immediately restarted the car. This time the car started fine and the engine idled smooth like it always had in the past. No rattle so… problem fixed! For the last two weeks the car has started normally and running fine until this morning when the same rattle occurred on cold start, coming from the passenger side valve cover. This time I had to restart the car 4 times before the engine stopped rattling. On the fourth startup the engine started normally. Common sense told me the timing change is making that noise and not to drive the car, but unfortunately, I had committed to taking friends to the airport for a flight to Tokyo and they and their luggage were already in the car and there flight was leaving in two hours. So with great hesitation, I departed for the 30 mile round trip to the airport. On the expressway the car ran as normal with no performance degradation that I could sense. So I’m looking for reassurance: Was it possible to have driven the car 30 miles to the airport at 80mph if the timing chain was broken, jumped a few teeth or if some valves are damaged? Would a loose timing chain cause intermittent rattling like I am experiencing or should I be looking at something else? I plan on taking my car in to get the chain checked but its Friday afternoon and that won’t happen until Monday so I’ve got 72 hours to run the worst case scenarios through my head as to what is making that rattling noise and if I have or am destroying my engine. Thanks for your replies.