1993 GMC Jimmy, L35 Engine (4.3L). The alternator gets quite hot. I've
also noticed that when the car has warmed up, if I stomp on the brake and
shift into park, the engine almost stalls, and cycles in speed a few times.
I posted this last week about the almost-stalling problem. Anyways, all
the sensors seem to check out and be okay, so I started looking for other
I took off the serpentine belt and checked all the pulleys. The alternator
turns with a lot more resistance than anything else. If I try to turn it
by hand (say, by flicking the cooling fan on it with my finger), it stops
within a quarter turn. I also get a "whine" sound when accelerating when
the engine bay is hot.
Is this consistent with alternator bearing wear? How easy should the
alternator be to turn by hand, with the car off and the belt disconnected.
My past experience with cars is that normally the magnetic field resistance
can be felt as you turn the pulley (several times as you go around), like
with an electric motor, but in the case I have here the resistance to
spinning is constant.
Anyone have experience with this? I've heard that these alternators run
hot anyways. I do know that a hot bearing/shaft will have less clearance.
Oh, as an added thing, I could swear that the alternator makes a scrape-
scrape sound when you start the car cold.