If the engine struggles to start, you may need a new starter. Keep in mind that it may just be your battery that's causing the problem.
Yes, a weak battery, dirty/loose battery connections and a bad starter solenoid can mimic the same conditions.
The altima uses a timing chain, not a belt.
start back at the battery, are the leads corroded? is there a clicking noise when the starter is engaged but the starter wont turn? are the leads from the battery to the starter in good condition. Usually any sign of a white powder around the battery or a lot of dirt is a sign of needing attention. The clicking could be a starter relay aor the starter itself needing replacement.
it looks as if there are small cracks on the pulley side of the belt. If these are within 1/8" of one another you need a new belt NOW
You hear noises coming from the alternator. The dash light for charging stays on. If not equipped with light might be a guage, in which case you see it not charging.
you will hear a rumbling or wining as you drive, especially at speed
Check to make sure your battery's charged up and the connections are all clean. If that's the case, then your starter's probably showing its first signs of laying down. Same thing went on with my Prelude, ended up just putting a new starter on it.
hopefully you will be installing a new starter...
water mixed in oil, check dipstick, looks milky in color. quick overheating. visible leaks around head gasket.
A slow crank or excessive power draw. Make sure that your battery is in good condition before condemning your starter.
on the starter
perhaps because the new starter is doing its job.... You think maybe it's supposed to start with the new starter in it?
No, just the opposite. A new starter will require less power to turn over than an older starter.