Replacing the water pump

Installation, removal and start-up on vehicles

Information on use

A water pump is usually driven mechanically by a toothed belt or V-belt and drives the cooling liquid (coolant, cooling water) through the cooling circuit of the engine in the car. What should you do if the pump is faulty and causes the engine to overheat? What must be taken into account when replacing a water pump and what mistakes could be made when installing or replacing a new coolant pump? This article shows how to replace and start up a new pump correctly and what to bear in mind for the seals, without causing irreparable damage to the component.

Dismantling the old water pump

Remove the old water pump in accordance with the manufacturer‘s instructions. Old fragments of the gasket and corrosion must be carefully removed from the sealing areas on the engine block. Abraded fragments of gasket must not get into the cooling system. If the cooling system is to be purged, this should be carried out prior to the dismantling of the old water pump for practical reasons.

Installing the new water pump

The cleaned sealing areas must be degreased prior to the installation of the new water pump to ensure that liquid sealants or gaskets are able to bond and seal well. In a housing sealed with elastomer seals, it may be necessary to apply some lubricant to the counter face of the engine block. This prevents the sealing ring from twisting, jamming or being damaged when the water pump is inserted.

Attention:
When installing the new water pump, it is essential to observe the tightening torques stipulated by the engine manufacturer and the tightening sequence of the screws.

Initial start-up

Attention:
The water pump must not be turned with a dry sliding ring seal.

The water pump must not be operated under any circumstances without cooling liquid having been poured in first. This requirement also applies to brief operations, such as checking whether the belt tension is OK or checking whether the engine starts up at all. If the water pump is operated without cooling liquid, both sliding rings rub dry against one another without any lubrication and without any cooling. This immediately leads to significant wear and thermal destruction of the sliding ring seal.

This is also the case if there is a loss of cooling liquid during the journey and the vehicle is driven to the next repair shop while the engine temperature is monitored. Even if only a short distance is covered, the water pump is normally irreparably damaged or destroyed as a result.

Video - Water pumps/ coolant pumps - basic information

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