Years ago, I had a 1996 Chevrolet S10 with the 2.2-liter engine, so when my friend had to replace the thermostat on the same truck with the 4.3-liter engine, I gave him a hand. Changing the thermostat on the 2.2-liter engine is just about the same as on the 4.3-liter engine, as I found out. To jack the truck up, we put the floor jack in the center of the front crossmember and put the jack stands under the lower control arms, inboard of the lower ball joints.
The thermostat housing is right up front. On the 4.3-liter engine, we had to take off the air cleaner, but once that was removed, it's right there. We had to pay special attention to the way the thermostat was oriented and put the new one in the same way. Before we put the housing back on, we put a 1/8-inch bead of RTV sealant in the groove on the water-outlet-sealing surface. We tightened the housing nuts to 21 foot-pounds, though I remembered on my 2.2-liter engine, I tightened the bolts to 18 foot-pounds. To refill the system, we followed the instructions from Chevy to use an ethylene glycol coolant such as Dex-Cool, mixed half and half with water.
