How to Replace a Mechanical Thermostat

The mechanical thermostat installed in the cooling system of an automobile is responsible for increasing the passage of radiator fluid through the engine when the vehicle surpasses optimum operating temperatures. When the engine gets hot, a spring located on the bottom of the thermostat compresses to allow additional fluid to pass. The most common location for a mechanical thermostat is inside of the intake manifold. This is the entry point of radiator fluid into the engine.

Instructions

1

Trace the upper radiator hose from the inlet tube on the radiator to the location where the hose connects to the intake manifold. The hose mounts to the thermostat housing, also called the T-Stat housing. Remove the hose from the housing by loosening the radiator hose band clamp with a screwdriver. In some cases, the clamp requires pliers so you can squeeze the compression tabs together to loosen pressure on the hose.

2

Remove the two bolts that secure the thermostat housing to the intake manifold of your vehicle. If needed, use a long well socket and extension bar to make it easier when reaching for the bolts.

3

Pull the thermostat housing off the intake manifold and then lift the old thermostat out of the intake.

4

Plug the hole in the intake manifold with a towel to prevent getting debris into the hole.

5

Scrape the old thermostat housing gasket material off the intake manifold and the bottom of the thermostat housing. Wipe both surfaces clean with a towel.

6

Remove the towel from the intake manifold and place the new thermostat into the hole. One end of the thermostat has a large spring on it. The spring submerges into the intake manifold. The thermostat sits on a machined lip inside of the hole.

7

Place a new thermostat housing gasket onto the intake manifold and line the holes up with the bolt holes in the intake.

8

Place the thermostat housing on top of the gasket and bolt it into place.

9

Reconnect the radiator hose and secure it with the radiator hose clamp.