The 2001 Chevrolet S-10 pickup was available with either a 2.2-liter Flex Fuel inline-four or a 4.3-liter V-6 engine. The thermostats in these engines help them reach operating temperature by restricting coolant flow when the engine is cold closed position and maintaining normal temperature in the open position. A thermostat can get stuck in either position. If stuck open, the engine will take a long time to warm up. If stuck closed a worse situation coolant flow continues to be restricted as the engine warms up. This can result in overheating.
Park the S-10 on a level surface and set the parking brake.2
Disconnect the negative battery cable with a wrench.3
Place a drain pan underneath the passenger-side corner of the radiator. Open the drain valve and allow about a gallon of coolant to drain into the pan. Close the valve. If the coolant is still clean, you can reuse it.4
Squeeze the ends of the hose clamp together with a pair of pliers and pull the upper radiator hose off the thermostat housing. If the hose clamp has been replaced with a screw-type clamp, use a flat-head screwdriver to loosen the clamp.5
Remove the bolts from the thermostat housing with a ratchet and socket. Remove the housing. Remove the thermostat, noting which way it faces into the engine. Remove the O-ring seal from the engine. Clean the housing and engine with a shop rag.6
Mount a new thermostat and O-ring in the engine. Install the thermostat housing and bolts. Use a torque wrench and socket to torque the bolts to 89 inch-pounds. Install the upper radiator hose.7
Pour the coolant -- if clean -- into the coolant recovery tank. Wait a few minutes and check the coolant level. Top off with fresh coolant if necessary. Start the engine and check for leaks.
Park the S-10 on a level surface and set the parking brake.9
Disconnect the negative battery cable with a wrench.10
Place a drain pan underneath the passenger-side corner of the radiator. Open the drain valve and allow about a gallon of coolant to drain into the pan. Close the valve. If the coolant is still clean, you can reuse it.11
Loosen the clamps on the air cleaner duct between the throttle body and air cleaner. Remove the duct. Use a ratchet and socket to remove the nuts from the throttle body bracket. Move the bracket out of the way to gain access to the thermostat housing.12
Remove the upper radiator hose.13
Remove the bolts from the thermostat housing. Remove the housing. Remove the thermostat, noting which way it fits in the engine. Clean the surface of the thermostat housing and engine with a shop rag14
Install the thermostat into the engine. This thermostat uses a rubber gasket similar to an O-ring that fits around the rim of the thermostat. If the new thermostat does not have the gasket mounted on it, slide the gasket onto the rim of the thermostat so the groove on the inside of the gasket fits over the rim.15
Install the thermostat housing and bolts. Use a torque wrench to torque the bolt to 14 foot-pounds. Mount the throttle body bracket back onto the throttle body, install the nuts and torque them to 89 inch-pounds.16
Refill the cooling system. Reconnect the negative battery cable. Start the engine and check for leaks.