Close
QUESTIONS

RepairPal is your advocate for car care advice and guidance

Q: how to replace thermostate on 1999 Lexus RX300

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
car overheating and then suddenly cools, sounds verymuch like a bad thermostste
No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
Get a Repair Estimate
Guaranteed by certified locations nationwide. Learn more
RepairPal estimates are guaranteed at over 1,700 quality certified locations nationwide. Learn more
Here is how to do it. If you need the supporting graphics you need to post an e-mail and I can send the whole thing to you.

REMOVAL
HINT: Removal of the thermostat would have an adverse effect, causing a lowering of cooling efficiency. Do not remove the thermostat, even if the engine tends to overheat.
1. DRAIN ENGINE COOLANT
2. REMOVE AIR CLEANER CAP AND AIR CLEANER CASE
3. DISCONNECT NO.2 ECT SWITCH CONNECTOR
4. DISCONNECT ENGINE WIRE PROTECTOR FROM WATER INLET AND RH CYLINDER HEAD
Remove the nut and disconnect the clamp, and disconnect the engine wire protector from the water inlet and cylinder head.
5. DISCONNECT WATER INLET PIPE FROM WATER INLET AND LH CYLINDER HEAD
1. Remove the bolt, and disconnect the inlet pipe from the water inlet.
2. Remove the O-ring from the inlet pipe.
6. REMOVE WATER INLET AND THERMOSTAT
1. Remove the 3 nuts, water inlet and thermostat.
2. Remove the gasket from the thermostat.

INSPECTION
Inspect Thermostat
HINT: The thermostat is numbered with the valve opening temperature.
1. Immerse the thermostat in water and gradually heat the water.
2. Check the valve opening temperature. Valve opening temperature: 80 - 84°C (176 - 183°F)

If the valve opening temperature is not as specified, replace the thermostat.
3. Check the valve lift. Valve lift: 10.0 mm (0.394 inch) or more at 95°C (203°F)
If the valve lift is not as specified, replace the thermostat.
4. Check that the valve is fully closed when the thermostat is at low temperatures (below 40°C (104°F) ). If not closed, replace the thermostat.

INSTALLATION

1. PLACE THERMOSTAT IN WATER PUMP
1. Install a new gasket on to the thermostat.
2. Align the thermostat jiggle valve with the upper stud bolt, and insert the thermostat in the water inlet housing.
HINT: The jiggle valve may be set within 15° of either side of the prescribed position.
2. INSTALL WATER INLET Install the water inlet with the 3 nuts.
Torque: 8 Nm (80 kgf-cm, 69 inch lbs.)
3. INSTALL WATER INLET PIPE
1. Install a new O-ring to the water inlet pipe.
2. Apply soapy water to the O-ring.
3. Connect the water inlet pipe to the water inlet.
4. Install the bolt holding the water inlet pipe to the cylinder head. Torque: 19.5 Nm (200 kgf-cm, 14 ft. lbs.)
4. INSTALL ENGINE WIRE PROTECTOR
5. CONNECT ECT SWITCH CONNECTOR
6. REINSTALL AIR CLEANER CAP AND AIR CLEANER CASE
7. FILL WITH ENGINE COOLANT
8. START ENGINE AND CHECK FOR LEAKS
9. RECHECK ENGINE COOLANT LEVEL


Zee
Didn't find what you were looking for?