Jim Grant's Tech Tips
'89 Mazda MPV, Alternator Noise
Ive got a whining noise on start up on my 89 Mazda MPV. The
whining eases off, comes back, eases off, comes back. After about 3 -
5 minutes it completely stops. Could this be an alternator going out?
I just had the timing belt and all components replaced - belts, tensioners,
idlers, water pump. The whine was there before the work was done but seems
quickest way to find out if it is the alternator or another belt driven
accessory would be to remove the belts. Allow the vehicle to set, cool
down, the length of time necessary for the condition to occur. Before
starting the vehicle remove the fan belt to the suspect accessory, in
your case the alternator. Then start the engine. If the noise is still
present remove the next belt. Perform these steps one at a time. When
the noise is gone you found the offending component.