Water pump oil leak

1999 MITSUBISHI TRUCK
100,000 MILES • 6 CYL • 2WD • MANUAL
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MILMAR_22
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We are maintaining a Fuso fight 6d17. The water pump failed by oil mixing with water and vice versa. We replaced it with a new one but after a few drive tests the oil leaks at the water pump shaft. We thought it was a factory defect so we returned it to the supplier to be changed by a new one but it happened again. Are we doing something wrong?
Jan 31, 2018 at 9:24 PM
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STRAILER
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You must be leaving out one of the o-rings that seals the the two sections. Did you match up the new unit to the old water pump? Sometimes the changes can be subtle.

Please let us know.

Cheers, Ken
Feb 2, 2018 at 4:29 AM
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MILMAR_22
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The new water pump is exactly the same as the old one. I am just wondering why the pressure is too high to worn out the oil seal of the water pump shaft and next thing you know, the radiator and fan are covered with oil. Would cutting out the oil supply be an option? Please help. Two brand new water pumps has been broken. Thanks Ken.
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Feb 2, 2018 at 9:48 AM
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STRAILER
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I do not see the oil problem? can you take pictures of the effected area?
Feb 3, 2018 at 2:17 AM
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MILMAR_22
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Hi Ken. This is where the oil comes out. We tried replacing it with a better oil seal but still.
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Feb 4, 2018 at 9:08 AM
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STRAILER
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When you say oil do you mean coolant? I do not see where engine oil is near the water pump like you say. Is the replacement pump OEM?
Feb 5, 2018 at 2:45 AM
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MILMAR_22
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It is engine oil. An oil type water pump. Engine oil is its lubricant instead of grease. The engine oil circulates to the water pump through camshaft.
Feb 5, 2018 at 5:44 AM
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STRAILER
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I see now, thanks. The only thing that can make the water pump go out is the pressure relief spring in the oil pump is stuck causing the oil pressure to be way to high knocking out the seal. Does the truck have a oil pressure gauge? Also was the pump a factory pump? Cheap pumps will fail not matter what happens.
Feb 6, 2018 at 2:49 AM
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