'96 Buick Regal Thermostat Installation

The 1996 Buick Regal was equipped with a 3.1-liter or 3.8-liter V-6 engine. The thermostat in these engines controls coolant flow. When the engine is cold, the thermostat is closed and coolant flow is restricted to get the engine to operating temperature soon as possible. As the operating temperature is reached and the thermostat opens, the coolant flow helps maintain operating temperature. An old thermostat can get stuck in the open position and make the vehicle take a long time to warm up, or in the closed position, which will cause the vehicle to overheat. In either case, the thermostat should be replaced. The method for replacing the thermostat is the same for both engine types.

Instructions

Removal

1

Park the Regal on a level surface and set the parking brake. Disconnect the negative battery cable with a ratchet and socket. Allow the engine to cool.

2

Open the radiator cap. Place a drain pan under the driver's side of the radiator. Open the drain plug and allow the coolant to drain into the pan. Close the drain plug. Clean coolant can be reused.

3

Follow the upper radiator hose to the thermostat housing. Loosen the hose clamp at the thermostat housing with a flathead screwdriver. Remove the upper radiator hose from the housing.

4

Remove the bolts from the thermostat housing with a ratchet and socket. Remove the housing. If it is stuck, tap the housing with a hammer handle to break it loose. Remove the thermostat, noting what end fits in the engine.

5

Scrape any old sealant from the housing and engine with a putty knife. Clean the surfaces with a shop rag dampened with acetone.

Installation

6

Install a new thermostat in the engine. Make sure the rubber seal is installed on the outside of the thermostat. Run a 1/8-inch bead of RTV silicone around the thermostat housing and a circle around each bolt hole.

7

Install the housing and bolts. Use a torque wrench and socket to torque the bolts to 18 foot-pounds for the 3.1-liter engine and 20 foot-pounds for the 3.8-liter engine. Install the radiator hose and tighten the clamp.

8

Open the bleeder screw on top of the thermostat housing three turns with a ratchet and socket. Fill the radiator with the old coolant if it is still clean or new orange General Motors DexCool or equivalent.

9

Start the engine. Air bubbles will escape from the bleeder screw. Add coolant to the radiator as needed to keep the radiator full. When the air bubbles cease and coolant is escaping from the bleeder screw, close it. Top off the radiator and replace the cap. Fill the coolant reservoir to the cold mark. Check for leaks.

10

Allow the engine to reach normal operating temperature. Let engine cool. Check the coolant level in the radiator and add coolant if necessary. Add coolant to the reservoir if necessary. Monitor the reservoir for the next couple of days and add coolant if needed.