97 Exlporer - Timing Chain rattle

On starting the vehicle (especially form cold, but also for instant when warm too), the rattling form the engine sounds like it very unhappy. I'm told it is the timing chain and one yard has indicated thats an engine out and huge cost which i can believe. But since it has only done 97500kms I can't believe it is a chain problem per se. Is it possible that it is in desperate need of some timing work? It runs fine on a run and doesn't grumble (rattle) if I push it hard? Any suggestions / help would be most appreciated. I don't have a service manual and will go get one if folks think it is a service item, but if it is a workshop job, I may as well get it in and fixed.