Water Outlet


  • Drain some coolant into a clean container until the coolant level is below the thermostat housing.
  • Remove the upper radiator hose connection from the thermostat housing.
  • Loosen the housing bolts and remove the housing.
  • Remove the gasket and scrape it carefully from the surface of the housing and the mounting surface on the engine.
  • If any gasket remains on either of the surfaces, there will probably be a coolant leak after reassembly.
  • Some engines use a rubber O-ring to seal a thermostat housing.

Installing the Water Outlet Housing

Install the thermostat with the temperature sensor facing into the block. If the thermostat is installed upside down, the engine will overheat. When possible, replace the housing with one made of the same material as the rest of the engine block or the cylinder head that it bolts to. For instance, install an iron housing on an iron head and an aluminum housing on an aluminum head. Be sure to position the hose clamp so as not to allow corrosion between the hose and the housing.

(a) Position the hose clamp near the ridge on the outlet housing. (b) This aluminum water outlet became corroded when the clamp was positioned improperly. Courtesy of Prestone Products Corporation.

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