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Auxiliary coolant pump repairing

Posted: Tue Jul 24, 2018 6:45 am
by xvert
I am not a blogger and photographer, but I think this is useful information for those who have a car equipped with an additional rear heater. Such cars have an auxiliary coolant pump (bosch) under hood.
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This pump probably does not work. This is the reason for the cold in the cabin in the winter. You can check condition of the pump simply: turn on the ignition (engine is off), turn on the a/c-heater fan ( or short-circuit the contacts 3 and 5 of the auxiliary coolant pump relay by wire) and open the hood. If the pump is functional, it emits a quiet buzz.
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If the pump is faulty, you can easily fix it if you replace the brushes of the electric motor. The size of the brushes is 5 * 5 "* 10 (mm), I made them from drill brushes (5 * 6 * 16) for 15min. (Before assembling, you need to fasten the brushes with a thread)
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There are other repair options:
-pull the outflow hose out of the pump and connect to the cooling line instead of the incoming hose (the pump interferes with the flow of coolant)
-buy a new suitable bosch pump for 19mm hoses ($ 50-100) and transfer the mounting bracket.
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