Something near the belt path, check to see if there are any loose covers touching. Something will have marks from the old belt rubbing it
It could be the timing chain guides. 240sx engines are notorious for this. The timing chain guides are made of cheap plastic and they wear out and break off after time. When the engine is started, the pieces get kicked up from the bottom of the oil pan and make a racket for a while. I don't think is causes much harm, though.
no it cant as, as long as the light isn't on
The voltage regulator in the alternator can cause issues like this when they start to go bad. The voltage regulator is an integrated part of the alternator and cannot be replaced, if it is bad, the entire alternator must be replaced.
Yes the ecu will work. First disconnect the battery and connect the new one then reconnect the batter. Start up the 240sx and it should work it not it needs to be diagnoste goggle 1990 240sx ECU CODES FOLLOW THE STEPS AND THAT SHOULD WORK I know cause I'm using a 1992 ECU FROM Nissan Stanza. I was told it's alittle advanced on the horse power side and idle moves quicker.
Something can be taxing the work of the alternator, or the alternator can be weak and needs replaced.
Even though you have already replaced the thermostat, there are other issues that can cause your Nissan Maxima to overheat. Your fan may be stuck and not operating as it should.
The ground cable, on the battery may need to be tightened or cleaned. The alternator voltage regulator may need to be replaced.
alternator or bad wires
If the alternator is bolted on too tight on its bracket,then it will cause the alternator to have a "bend" so that the clearance between the moving parts is reduced and the moving parts eventually jammed.
four people can fit in a 240sx fastback cause there are only 4 seatbelts
The Alternator is not putting out enough voltage. If you recently replaced the alternator with a "new" remanufactured alternator that one could be bad to your truck somewhere to get it tested.
Try an ignition switch.