GM 12597172
Thermostat Housing, Green Line

To perform the replacement of the engine coolant Thermostat housing (RPO L61), first take off the intake manifold cover and drain the cooling system, allow the use of the drain found at the lower part of the Water Pump for the engine block coolant drainage. Once this is done, close the drain bolt and bring down the vehicle. For automatic transaxle models, do not disconnect the engine coolant temperature (ECT) sensor electrical connector; for manual transaxle models do the same thing. Knock off the heasng Oxygen Sensor heater (HO2S) electrical connector clip from the Thermostat housing and if necessary, remove the ect sensor. Position the radiator outlet hose clamp used to be in a new location and remove the radiator outlet hose from the Thermostat cover. Next, dismount the Exhaust Heat Shield studs and the Exhaust Heat Shield. Reposition the heater inlet and outlet hose clamps at Thermostat housing pipes, then remove heater inlet and outlet hoses(1, 2) lift and prop up the vehicle, then just pull the Thermostat housing bolts and twist the water transfer pipe as you pull it away from the Water Pump. Take off the Thermostat, as well as the pipe transferring water to it (on the Thermostat housing) if needed and throw away the o-ring seals if any. Unscrew the Thermostat cover bolts and cover, and clean all debris and thread sealant from the ect sensor and bolt holes if reusing the housing. Install: put a new Thermostat cover o-ring seal into the recess groove, install the Thermostat if necessary, tighten the Thermostat cover bolts to 10 n.m (89 lb in). Mount a new Thermostat housing to engine gasket on to the Thermostat housing, ensure that the water feed pipe seals are lightly lubricated with coolant before putting in new o-ring seals onto water feed pipe; ensure that these seals are lubricated with only coolant. Put the water feed pipe in the Thermostat housing noting the locator tab, strapping it to the Water Pump and using care to seat the o-ring seal. Mount the Thermostat housing on the engine and tighten it to 10 n.m (89 lb in) housing bolts. Lower the vehicle and hook the heater inlet hose (1) and outlet hose (2) up to the Thermostat housing pipes, fasten the hose clamps. Re install the Exhaust Heat Shield and tighten studs to 22 n.m (16 lb. Ft.). Secure the radiator outlet hose onto the Thermostat cover and place the radiator outlet hose clamp. If replacing the old sensor, apply a coat of sealant on the threads before installing the ect sensor and securing it to 20 n.m (15 lb ft). Attach both manual and automatic transaxle models ect sensor electrical connector and then attach the ho2s electrical connector plug to the Thermostat housing. Level the vehicle as you fill the cooling system, make sure that drain valves on the radiator and Water Pump are closed, lower the vehicle, fill the cooling system, and lastly, attach the intake manifold cover.

To perform the replacement of the engine coolant Thermostat housing (LE5), one must take into consideration draining the cooling system utilizing the given drain at the bottom side of the Water Pump for the purpose of engine block coolant drainage. Take off the Water Pump Drain Plug to drain coolant off the engine block and then lower the vehicle. Remove the bracket and disconnect the engine coolant temperature (ECT) sensor and the heated Oxygen Sensor (HO2S) electrical connector clip. Before you remove the radiator outlet hose, you should remove ect sensor and surge tank outlet hose as well as reposition the radiator outlet hose clamp. Next, undo the bolts that hold the Exhaust Heat Shield and take out the heat shield, then reclamp and take off the heater inlet and outlet hose clamps from the Thermostat housing pipes. Before taking the Thermostat housing off, remove the Thermostat housing bolts by twisting the water transfer pipe and pull it off the Water Pump. Removing the Thermostat housing. If needed, remove the water transfer pipe from the Thermostat housing and dispose of the o-ring seals. Undo the Thermostat housing cover bolts and housing cover, the Thermostat if necessary while making sure to clean any debris and thread sealant from the ect sensor and bolt holes if the housing is to be used again. Again for installation, fit a new Thermostat housing o-ring seal to the recess groove, fit the Thermostat if it is required, and bolt the cover to 10 nm (89 lb/ in). Install a new Thermostat housing to engine o-ring seal on Thermostat housing, load the assembly into place, and lubricate the water feed pipe seals with a little coolant. Place new o-ring seals on water feed pipe and put it into the Thermostat housing properly align with the locator tab and seat the o-ring seal press toward the Water Pump, and avoid damaging it. Placed the Thermostat housing against the engine and tighten the housing bolts to 10 nm (89 lb in) and reconnected the heater inlet and outlet hoses to the housing pipes of the Thermostat making sure that the clamps are well in position. Reinstall the Exhaust Heat Shield along with the bolts and tighten them to 23 nm (17 lb ft) and fit the radiator outlet hose to the Thermostat housing and tighten the surge tank to the housing using clamps. Seal the threads of the ect sensor, mount it, and tighten to 20 nm (15 lb ft), then reconnect the ect sensor electrical connector and the ho2s electrical clip connector. Finally, apply sealant gm p/n 12378521 (Canadian P/N 88901148) or equivalent to the Water Pump Drain Plug, install it, and tighten it to 20 nm (15 lb ft). Make sure the vehicle is leveled, check the shut off of the drain valves located on the radiator itself and Water Pump, fill up the cooling system, and check for any leaks to guarantee the fix.

Before starting Thermostat housing replacement for rpo l61 vehicles begin by draining the coolant system through the water pump drain before tightening the drain bolt. Before proceeding drop the vehicle or unplug the engine coolant temperature (ECT) sensor electrical connector for automatic transaxles or manual transaxles whenever possible. When required you will need to remove the ect sensor followed by relocating the radiator outlet hose clamp before extracting the hose from the Thermostat housing. Begin by removing the nuts from the air cleaner bracket and continue with the Exhaust Heat Shield studs before extracting the Exhaust Heat Shield. Reposition all heater hose clamps and disconnect ventilation hoses from their corresponding pipes on the Thermostat housing then lift the vehicle upward. Remove Thermostat housing bolts (3, 4) before twisting the water transfer pipe to separate it from the water pump. You should remove the water transfer pipe from the Thermostat housing before discarding both o-ring seals. Extract the Thermostat housing cover bolts and cover and the Thermostat before discarding the applicable o-ring seal from the Thermostat housing. Clean all material and thread sealant from the engine Coolant Temperature Sensor and bolt holes when using the same housing. Place a new o-ring seal on the recess groove before installing the Thermostat housing cover bolts to 10 nm (89 inch lbs.) and attaching the Thermostat when needed. After putting the new Thermostat housing to engine gasket into position carefully fit the assembly and apply a light layer of coolant to the water feed pipe seals before adding new o-ring seals to the pipe ends. Position the water pipe next to the water pump then install the water feed o-ring seal afterward position the Thermostat housing against the engine. Screw on Thermostat housing bolts (3, 4) to 10 nm (89 inch lbs.) before lowering the vehicle. Finally, install the heater inlet and outlet hoses to their respective pipes on the Thermostat housing while positioning clamps correctly. Use the Exhaust Heat Shield by tightening the studs above 22 nm (16 ft. Lbs.). Reinstall the air cleaner bracket after tightening its nuts at 10 nm (89 inch lbs.). After reinstalling the radiator outlet hose onto the Thermostat housing, position theclamp and place the ect sensor in position if necessary. After hooking up the ect sensor electrical connector for manual systems the technician must install the ho2s electrical connector clip on the Thermostat housing. The first step is maintaining vehicle levelness before adding coolant solution and checking drain controls at both radiator and water pump locations for closure. The repair can be verified through a leak inspection after lowering the vehicle.

If necessary, remove the water transfer pipe from the thermostat housing and discard the O-ring seals.

Take off the thermostat cover bolts and cover, followed by the thermostat itself, and discard the thermostat cover O-ring seal if applicable.

Install the radiator outlet hose to the thermostat cover and position the radiator outlet hose clamp at the thermostat cover.

Remove the thermostat housing and the water transfer pipe if necessary, discarding the O-ring seals if applicable.

Finally, fill the cooling system.

First, drain the cooling system.

Align the water pipe to the water pump and seat the water feed O-ring seal by pushing inward toward the water pump without damaging it.

Clean any debris and thread sealant from the engine coolant temperature sensor and bolt holes if reusing the housing.

Install the water feed pipe into the thermostat housing, aligning the locator tab, and then align the water pipe to the water pump and seat the water feed O-seal by pushing inward.

Reattach the radiator outlet hose to the thermostat cover and position the radiator outlet hose clamp at the thermostat cover.

Carefully remove the thermostat and retaining sleeve, noting their orientation for reinstallation.

Remove the thermostat housing bolts, twist the water transfer pipe while pulling to detach it from the water pump, and then remove the thermostat housing.

Place a NEW thermostat housing cover O-ring seal.

Start by placing a new thermostat cover O-ring seal, then install the thermostat.

Reposition the radiator outlet hose clamp at the thermostat housing and remove the radiator outlet hose.