How to Replace the Thermostat on a 1997 Cutlass
by Kyle McBrideWhen I think of all the cars I've owned, my 1997 Cutlass with the 3.1-liter V-6 was my favorite. It gave me very little trouble, though I remember one time I was driving around town and it overheated. Turns out the thermostat stuck closed and I had to replace it. Replacing the thermostat wasn't a problem after removing the air cleaner assembly, but draining and refilling the cooling system was a bit of a challenge.
Pesky Petcock
To lift the front, I put the floor jack in the center under the crossmember and then put jack stands under the frame behind the front wheels. To get to the petcock so I could drain the cooling system, I had to remove the lower splash shield. The petcock was next to the condenser-to-radiator bolt and faces forward. It's made of plastic and it was stubborn to open. I sprayed it with some penetrating lubricant to free it up so I didn't I break it trying to get it open.
Burping the System
I torqued the thermostat bolts to 18 foot-pounds. I refilled the cooling system with a 50 percent solution of good-quality ethylene glycol antifreeze and drinking water. I had to remove the bleedscrew on the water outlet housing and then replace it when the coolant started to bubble out. I almost forgot put the bleedscrew back in before I started the engine, which would have sucked air into the system.
