Thermostat Replacement

Covers:

• 1993-1997 2.0L 4-Cylinder Engine

Thermostats control the temperature of the engine coolant. This can effect engine operation, performance, and the heating system. If a thermostat is stuck open or opens prematurely, the coolant temperature will stay too cool, affecting the air/fuel ratio as well as the heating system. Symptoms include poor heating by the climate control system. If a thermostat is stuck closed or stays closed past the specified temperature, the engine can overheat, causing poor engine performance and and possible engine damage. Many people unfamiliar with engine maintenance or operation don't know what the thermostat does nor even where it's located. This causes the thermostat to be often overlooked when diagnosing coolant system problems.

Changing the thermostat is relatively easy and very inexpensive. Most thermostats cost between $5 and $10.

Overview

The thermostat is located in the thermostat housing and covered by the water inlet housing. The water inlet housing is where the lower radiator hose connects to the engine. DO NOT service the coolant system until the engine cools.

Parts Required

• New thermostat (195° F)

• Coolant

Tools Required

• Wrench/sockets

• Scraper or razor blade

• Torque wrench

Removal

1. Remove the radiator cap. Place a bucket or pan under the radiator drain plug (lower end of radiator, toward passenger side) and drain the coolant (See Image #1, below). A 3/8" hose can be connected to the outlet to direct the coolant during draining.

2. Replace and hand tighten the radiator drain plug.

3. Remove the clamp from the lower radiator hose at the water inlet housing and disconnect the hose.

4. Remove the two bolts from the water inlet housing and remove the housing. It may stick, so light prying may be required, but be careful not to damage the water inlet housing or thermostat housing.

5. Remove the thermostat from the engine.

6. Using a scraper or razor blade, carefully clean all the old gasket material from the water inlet housing and the thermostat housing. Make sure the surfaces are clean and smooth to assure proper sealing when reinstalled.

Installation

1. Place a new thermostat into the thermostat housing. The tab on the thermostat should be at the top and aligned with the recess in the thermostat housing. The side with the spring should be facing the thermostat housing.

2. Install the water inlet housing on the thermostat housing and tighten the two bolts to 14-18 ft/lbs.
3. Reconnect the lower radiator hose and replace the clamp.
4. Refill the radiator with new coolant (50/50 mix of coolant and water).
5. Set the climate control system to the maximum heating position. Start the engine and allow it to warm. Shut off the engine once the upper radiator hose feels warm (indicating the thermostat has opened).
6. Check the coolant level and add if required.
7. Reinstall the radiator cap.
8. Add new coolant (50/50 mix of coolant and water) to the radiator overflow container (left of radiator cap). Fill to the 'F' mark on the cap.

Notes

• Do not reuse old coolant. Replenish the coolant system with new coolant only.
• Use a 50/50 mixture of coolant and water. More water can be added for slightly improved cooling (55/45 mixture), but do not exceed a 60/40 mixture.

Image #1