2000 Frontier nissan believe the timing chain broke.
 

Good evening, my father owns a 2000 nissan frontier and last thursday at a stop light, when he went to take off the engine died. When he started the engine again it did not start but, he said that the starter seemed to turn at a very high rate of speed but the engine did not turn over. He seems to think the timing chain broke. It has 225,000 on it. It is way over due for one. He has changed the oil religiously at intervals of 2500 miles. He is 84 and not very able to work on it, nor has the money to take to a shop. I have to do the work and not very good as a mechanic. My question is has anybody on this forum replaced a chain, on a 2000 frontier. Also if anybody has had a broken chain while running how much damage to the valves? Any help would be greatly appreciated at this point. I have a shop manual as well as a regular manual on the truck. Just looking at any advice before I get to work on it this weekend. I have not touched it yet.

Don't try to start the engine again, to prevent any major issues. I am not a mechanic but I am just saying based from my experience. If it is a timing chain, I think you don't have to worry of making damage to the valve because timing chains don't break. If it is a timing belt, that is where it breaks and cause damage to the valves if you insist on starting the engine.

parker43, thank you for your reply. I am not a mechanic either, but going to try to help my father out on the engine. I am stumped as if it is a chain or belt. I have seen you tube videos on the same same year truck and one guy had a belt, the other guy had a chain. I am going to attempt to take it all apart tomorrow Friday. I will be seeing what it is by end of day. Will have an update soon.

Update.
 

Got the top cover off the engine. Chain is in tacked, however the left sided chain guide broke about 3inches from the top. So we proceded to take the bottom cover off. Got stuck at the distributor. It will not budge. Removed the bolt, also the rotor spins freely. Can not remove the distributor. Is it possible it is jammed on the drive gear?