Thermostat Housing Replacement Cost Estimate

A damaged thermostat housing will leak engine coolant when the engine is up to operating temperature. The leak could originate from a crack in the housing, or it could come from a broken seal between the housing and the engine. Thermostat housings with rubber seals will need to be inspected for warpage in the event of a leak at the seal, and if no warpage is found, the runner seal can be replaced.

The thermostat housing is replaced once the engine has cooled down completely. A technician will unscrew the fasteners that hold the housing in place and remove the old part. The gasket or sealing material is cleaned from the mounting surface, and a new seal is installed. Once the new housing has been installed, the engine is started and brought up to temperature. Any lost coolant is replaced. If the thermostat is connected to the lower radiator hose, the technician will have to drain the coolant before removing the thermostat housing. In either case, once the coolant has been restored, any air that is trapped in the cooling system must be removed. Sometimes, a technician will use a special vacuum tool to remove the air before adding the coolant.

RepairPal recommends that the cooling system be thoroughly inspected by a qualified technician at a trusted repair facility as soon as possible when signs of overheating or coolant appear. Also, ensure you are following the factory scheduled maintenance for the vehicle as the thermostat housing may be part of these services.

An engine in a late model vehicle is designed to run somewhere between 185 and 220 degrees. But the fluid in the cooling system can rise well in excess of 220 degrees when the engine overheats. This produces steam that will cause severe injury from scalding if the system is opened when hot and under pressure. Burns are possible as the engine components are also at a high temperature. Extreme caution should be exercised when working on a hot engine, especially one that is overheated. If steam is seen coming from under the hood, the engine should be allowed to cool for at least a half hour before the hood is opened, and the radiator cap or coolant reservoir cap should not be removed until the engine is cool enough to touch with a bare hand.

The cooling system is typically serviceable by the DIY mechanic, however, following guidelines for properly bleeding the engine coolant system of air is mandatory to prevent overheating and damage to the engine. If the thermostat housing has warped, cracked, or leaked with no other issues to the cooling system, it can be replaced easily by nearly anyone who follows proper safety, replacement, and bleeding procedures.