Thats what my water pump sounded like before it began to leak. Keep an eye on your coolant level and think about whether or not that you want to do this job. By the way, mine made the noise off and on randomly and then I noticed coolant leakage that progressively got worse.

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T