When my '81 W123 240D is thoroughly warmed up (not when it's first started) it makes an intermittent clicking or chirping noise. It's coming from the area of the alternator and when you squirt water directly on the alternator belt , the noise stops until the belt dries off. I replaced the alternator and still hear the noise. The only other thing on that belt is the water pump which i replaced about a year ago. The belt also looks good. Any theories? Thanks.