How To: Replace Thermostat

[92Lex]

Remove air duct so you'll have more room to work with (1)10mm screw:

[92Lex]

Drain coolant, then disconnect radiator hose from thermostat housing:

[92Lex]

Remove thermostat housing (2)10mm nuts:

[92Lex]

Remove thermostat and replace....make sure you keep the air bleed towards the top, then install everything is reverse order that you removed them:

[Lexls]

What about draining the coolant? I would think you would have a massive mess if you didn't do that first...

[92Lex]

Not much comes out though...I changed my thermostat after I refilled my coolant because I forgot all about it. But yeah, draining like a 1/4 gallon of coolant wouldn't be a bad idea.

So like Lexls said....you could drain some of the coolant, that way you'll avoid the mess. After you're done installing the new thermostat just top it off with a 50/50 mixture of Toyota coolant.

[92Lex]

If you have any questions, please don't hesitate to email me.

[cmonge]

Remove air duct so you'll have more room to work with (1)10mm screw:

Where exactly is the housing located? The photos you had do not show up anymore. Is it located on the block where the top radiator hose connects to the engine or is it on the bottom of the block where the lower hose attaches?

Any info would be greatly appreciated. I have a 2004 RX 330 that needs a new thermostat.

[cmonge]

Remove air duct so you'll have more room to work with (1)10mm screw:

Where exactly is the housing located? The photos you had do not show up anymore. Is it located on the block where the top radiator hose connects to the engine or is it on the bottom of the block where the lower hose attaches?

Any info would be greatly appreciated. I have a 2004 RX 330 that needs a new thermostat.

If anyone has any photos of this I'd appreciate you sending them to me.

C.

[fuji0030]

1.

Step 1

Go to your local auto parts store and purchase a new thermostat, gasket and gasket sealant for your particular make, year and model car.

2.

Step 2

Open the radiator cap, but before you do, place a thick rag like a bath towel over the cap on the radiator and slowly turn it while listening for the pressure to be released. When it stops remove the cap completely.

3.

Step 3

Locate the thermostat by finding the two-inch thick black hose coming out of the top of the radiator. The hose will end somewhere on the top of the engine and it will be clamped onto the thermostat cover. The cover will have two bolts on each side.

4.

Step 4

Remove the hose by using the screwdriver or pliers to pull off the clamp. Some auto manufacturers use stainless steel clamps with a screw and some use a clip clamp.

5.

Step 5

Twist the hose to loosen it from the thermostat cover. Use the spray lubricant if the hose is difficult to loosen. Be aware that a considerable amount of coolant will pour out of the hose when you take it off.

6.

Step 6

Loosen the two bolts on each side of the thermostat cover with the appropriate-sized ratchet socket or open-ended wrench. Lift the cover off and remove the thermostat.

7.

Step 7

Use the putty knife or scraper to remove the old gasket from the thermostat cover and cover base.

8.

Step 8

Use an emery cloth to sand away any remaining traces of the gasket. Make sure the cover and cover base are smooth and clean or the cover will leak.

9.

Step 9

Drop the new thermostat with the spring mechanism down into the engine. Notice there is a narrow recessed area where the top of the thermostat fits.

10.

Step 10

Spread the gasket sealant on the thermostat cover that makes contact with the engine and on the cover base. Place the gasket on the cover base, making sure the bolt holes line up.

11.

Step 11

Replace the thermostat cover and screw the bolts in place.

12.

Step 12

Replace the radiator hose.

13.

Step 13

Wait for the gasket sealant to dry before starting the engine. Read the directions on the sealant package to determine how long the sealant needs to dry.

14.

Step 14

When dry, start the engine and run it until it reaches the engine’s normal operating temperature. Check the thermostat cover and hose to make sure there are no leaks.

15.

Step 15

Check the coolant level and replace what is needed.

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Thermostat