I have been hearing a low pitched whining noise intermittently from the engine compartment when the motor is running. I also noticed the voltmeter needle was lower than normal, around 10-11 volts. Normally the needle is pegged right in the middle on the 14 volt mark but it was halfway between that and 0. I figured it was time for a new alternator and installed it today but alas... It still shows the same reading. Any ideas?