If your 1997 Blazer constantly overheats, then chances are your thermostat requires replacement. The thermostat is special valve that controls the flow of coolant to the engine. The thermostat responds to changes in temperature by way of a wax pellet that melts and expands as engine heat increases, causing the valve to open and allow coolant to flow through the engine. When the thermostat becomes stuck in either the open or closed position, it should be replaced as soon as possible.
Instructions
- 1
Park the Blazer on a level surface and open the hood. If you recently drove the vehicle, allow the engine to cool before working on the cooling system. Locate the radiator drain plug along the bottom of the radiator and position a drain pan underneath it.
2Slowly open and remove the radiator cap and then remove the radiator drain plug at the bottom of the radiator with an open-end box wrench. Allow all of the coolant in the radiator to drain out. When finished, replace the drain plug and tighten it with the open-end box wrench.
3Locate the upper radiator hose at the top of the radiator and follow it to the thermostat housing located in the middle of the engine. Undo the heater hose clamp with a slotted screwdriver and remove the heater hose from the thermostat housing. Allow any trapped coolant in the hose to drain into the drain pan.
4Use a ratchet and socket to loosen and remove the two bolts securing the thermostat housing to the engine. Lift the housing off the engine to reveal the thermostat. Note the orientation at which it is facing, as it must be installed in the same manner. Remove both the thermostat and its gasket. Use the slotted screwdriver to scrape away any remaining gasket and other residue.
5Make sure the thermostat's jiggle valve is positioned at the top of the thermostat when installing. Drop the thermostat into place, and then place the new thermostat gasket over the mounting surface. Place the thermostat housing over the thermostat and reinsert the two retaining bolts. Tighten the two bolts to 14 foot-pounds using a torque wrench. Fit the upper radiator hose over the thermostat housing and secure it with the hose clamp.
6Refill the radiator with fresh GM Dexcool or equivalent engine coolant until it is full. With the radiator cap still off, start the engine and allow it to run until it achieves normal operating temperature, adding more coolant as necessary. Check for leaks underneath the front of the engine and the radiator area. When the engine is at normal operating temperature, replace the cap on the radiator and turn the vehicle off. Fill the engine coolant reservoir with fresh coolant until it reaches the full mark.
7Remove the drain pan from underneath the Blazer and properly dispose of the used coolant. Engine coolant is poisonous to both animals and children, so it should not be poured onto the ground or into storm drains.
