How to Change the Thermostat on Volkswagen Cars

by Contributing Writer; Updated June 12, 2017

It shouldn't come as too great a shock to find out that the thermostat on your Volkswagen car is one of the more crucial parts when it comes to monitoring and regulating the internal temperature of your Volkswagen car. It is essentially a heat-triggered valve that allows coolant from your radiator to flow into your Volkswagen car once a certain operating temperature is reached. The hotter your Volkswagen car gets, the wider the thermostat opens, and the more coolant gets pumped into your Volkswagen car to cool it back down. Because of wear and tear--and because it has liquids flowing around it almost constantly--thermostats will have to be replaced periodically as they break down or become rusty, otherwise you risk overheating your car.

Under The Hood:

 How to Change the Thermostat on a 2.8 VW Engine

Locate your thermostat housing. This can be done by starting at the large hose connected to the top of your radiator and following it to where it connects to the engine. The housing on the other end of the hose can be removed, and you will find the thermostat underneath.

Use your wrench or your ratchet and socket to remove the thermostat bolts securing down the thermostat housing. Bolt sizes will vary depending on the model and year of the vehicle in question.

Pull back the thermostat housing to expose the thermostat. Note how the thermostat is oriented, and then remove it from the engine. Once you have the thermostat, you may discard it.

Use your razor blade or scraper tool to remove the remains of the thermostat gasket from the engine and from the housing.

Coat the bottom of the thermostat housing with a light layer of gasket sealant. Place the new gasket--it will have come with the thermostat when you purchased it--on the sealant, making sure that the gasket is oriented correctly to the housing.

Place the new thermostat into the engine block and orient it the way you noted in step 3.

Re-set the thermostat housing over the thermostat and screw the bolts back in to tighten it down.

Items you will need

  • Replacement thermostat

  • Wrench or ratchet and socket

  • Gasket sealant

  • Razor blade or scraper tool

 How to Change the Thermostat in a 2000 Jetta VR6

Locate the thermostat intake tube by following the radiator hose from the radiator to the point where it connects to the VR6's intake. Remove the intake tube bolts with a 10 millimeter wrench. Lift the intake tube of of the manifold and push it to the side to expose the thermostat.

Pull the old thermostat out of the intake manifold and replace it with a new one. The thermostat sits on a lip that is below the radiator fluid level. There will be an arrow indicator showing which end of the thermostat must stick out of the manifold.

Remove the old thermostat gasket and replace it with a new one. The old gasket can be removed with our fingers but in some cases a scraper may be needed to free the gasket from the surface of the intake.

Bolt the thermostat intake tube back onto the manifold of the Volkswagen.

Items you will need

  • Wrench

  • 2000 Jetta VR6 thermostat

  • 2000 Jetta VR6 thermostat gasket

 How to Replace a Thermostat on a VW Jetta 2001

Locate the thermostat housing by following the upper radiator hose from the radiator to the location where the hose connects to the engine block. The cover that the hose connects to is called the thermostat housing.

Remove the radiator hose from the radiator housing. Squeeze the tabs located on the radiator clamp together with a pair of pliers. Slide the clamp upward onto the hose and then pull the hose off the thermostat housing. Lift up on the hose to drain any fluid left in the hose back into the radiator.

Remove the thermostat housing by removing the two bolts that hold it into place with a wrench.

Take note on how the thermostat is positioned in the intake manifold of the Jetta and then pull it out of the intake by pulling upward on it. Place the new thermostat into place so it is orientated in the same manner as the old thermostat.

Pull the old thermostat gasket off of the intake manifold and replace it with a new one.

Bolt the old thermostat housing back onto the intake manifold.

Secure the radiator hose onto the thermostat housing and secure the radiator hose clamp.

Items you will need

  • Pliers

  • 12-mm wrench

  • Thermostat gasket

  • Thermostat

 How to Replace a Thermostat on a 2003 VW Jetta

Park the Jetta on level ground and allow the engine to cool down completely. Lift the hood and prop it open. Take off the radiator cap with your hand. Put the large drain pan under the radiator and open up the drain valve on the base of the radiator with your hand. Tighten the valve once all of the coolant has drained.

Locate the thermostat housing on the front of the engine block, connected to one of the radiator hoses. Unbolt the housing with the 3/8-inch ratchet and socket. Pull the thermostat and its O-ring out of the housing.

Install the replacement O-ring in the thermostat housing by hand. Insert the replacement thermostat into the housing, then bolt the housing to the engine with the 3/8-inch ratchet and socket.

Fill the radiator with the 50/50 pre-diluted coolant and reattach the radiator cap. Start the engine. Turn the heater to its highest setting and run the Jetta until the temperature gauge reaches the halfway mark of the gauge. Let the engine cool for at least two hours.

Remove the radiator cap. Add any necessary coolant to the system. Reattach the radiator cap and close the hood.

Items you will need

  • Large drain pan

  • 3/8-inch ratchet and socket set

  • Thermostat O-ring

  • 50/50 pre-diluted coolant

 How to Replace the Thermostat on a 2000 VW Beetle

Remove the radiator hose from the thermostat intake tube by loosening the band clamp that secures the hose to the intake tube. To do this, turn the cam on the band clamp counterclockwise with a screwdriver.

Pull the radiator hose off the thermostat intake tube and hold the hose vertically while the radiator fluid drains back into the engine. This will prevent radiator fluid from getting on the engine block. With the hose drained, push it to the side to access the intake tube.

Remove the thermostat intake tube by taking off the bolts that hold it onto the intake manifold. With the bolts removed from the intake, pull the intake tube off. Inspect the tube for hairline cracks. If there are any hairline cracks, replace the intake tube.

Pull the old thermostat gasket off the intake manifold and discard it. Place the new thermostat onto the intake manifold. Do not get the thermostat gasket wet. If it gets wet, it will compromise the seal between the thermostat intake tube and the intake manifold.

Pull the old thermostat out of the intake manifold and discard it. Place the new thermostat into the intake manifold. One end is marked "top." Submerge the opposite end into the intake manifold to ensure the thermostat works properly.

Bolt the thermostat intake tube back onto the intake manifold with the original bolts.

Secure the radiator hose to the thermostat intake tube by tightening the band clamp. Turn the cam clockwise with a screwdriver to do this.

Start the engine and let it run. Check the seal between the radiator hose and the thermostat intake tube. If you see a leak, tighten the hose. Check the mating surface of the thermostat intake tube and the intake manifold. If there is a leak, tighten the thermostat intake tube.

Items you will need

  • Screwdriver

  • Wrench

  • Thermostat gasket

  • Thermostat

 How to Change the Thermostat in a Volkswagen 2.0 Engine

Remove the Thermostat

Remove the cap from the coolant reservoir.

Raise the front of your Volkswagen with a floor jack and support it on two jack stands.

Detach the insulation tray from the bottom of the radiator using a ratchet and socket, if your particular model is equipped with one.

Place a catch pan underneath your Volkswagen radiator.

Open the radiator drain valve and drain the coolant. Then close the drain valve.

Follow the lower radiator hose toward the engine and loosen the hose clamp at the flange attached to the engine. Use a screwdriver, slip joint pliers or ratchet and socket, depending on the type of clamp used on your particular model.

Remove the two mounting screws from the radiator hose flange using a ratchet and socket.

Detach the flange from the engine, O-ring and thermostat.

Install New Thermostat

Set the new thermostat in place. Make sure the spring points toward the engine.

Place a new thermostat O-ring.

Set the thermostat flange in place and start the two mounting bolts by hand. Then tighten the bolts using the ratchet and socket.

Attach the lower radiator hose to the flange and tighten the hose clamp using the screwdriver, slip joint pliers or ratchet and socket.

Lower the vehicle.

Fill the coolant reservoir with 40 percent anti-freeze and 60 percent water up to the upper line or the MAX mark on the reservoir tank.

Replace the cap on the coolant reservoir.

Start the engine and run it at 2000 rpm for 3 minutes. Then let it idle until the cooling fan comes on and turn off the engine.

Open the reservoir cap carefully using a shop rag and release the steam. Add more coolant mixture to bring the level up to the upper line or MAX mark again. As you operate the vehicle, keep checking the coolant level at the reservoir and add more until the level stays at the upper line or MAX mark with the engine cool.

Items you will need

  • Floor jack and two jack stands Ratchet and socket Catch pan Screwdriver or slip joint pliers if necessary New thermostat O-ring New anti-freeze Shop rag

 How to Change the Thermostat on a Passat

Place a drain pan under the petcock on the bottom of the radiator. Open the petcock with a pair of pliers, and drain the coolant from the radiator into the drain pan. Close the petcock.

Locate the water inlet housing by following the lower radiator hose. Remove the clamp that secures the radiator hose to the housing by using a pair of pliers. Pull the hose off the housing.

Remove the nuts that secure the water inlet housing to the water pump using a socket and ratchet.

Pull the housing off the water pump. Take note of the thermostat positioning inside the water pump. The thermostat has an arrow on it located between the two studs on the pump. When you place the new thermostat into the pump, make sure the arrow is in the same position it was on the thermostat you removed.

Pull the used thermostat out of the water pump. Place the gasket onto the new thermostat, and place the thermostat into the housing.

Place the water inlet housing onto the water pump, and secure it using the socket and ratchet.

Slide the hose onto the water inlet housing, and secure it using the clamp and pliers.

Remove the radiator cap on the top of the radiator. Place a funnel into the filler spout, and pour the coolant back into the engine. Put the cap back on the radiator.

Items you will need

  • Pliers

  • Drain pan

  • Socket set

  • Funnel

 How to Change a Thermostat in a Volkswagen Touareg 4.2

Locate the thermostat cover where the top radiator hose connects to the top of the engine. The metal part that the hose connects to is the thermostat cover; this cover is connected to the Touareg's air/coolant intake manifold.

Remove the bolts that hold the thermostat cover onto the the intake manifold with a 10 mm wrench then pull the cover off of the intake manifold. This will expose the mechanical thermostat. Push the radiator hose off to the side so you can access the thermostat easily.

Pull the old thermostat out of the intake manifold and replace it with a new OEM (original equipment manufacturer) thermostat. The end marked "Top" must stick out of the engine. Thermostats are available at most auto parts retailers or Volkswagen dealerships.

Remove the carbon gasket sandwiched between the cover and the intake manifold and replace it with a new OEM gasket. These are available at most auto parts retailers or Volkswagen dealerships.

Bolt the thermostat cover back into place. Do not overtighten the thermostat cover as it's possible to crack it. If the cover does crack, it should be replaced, not repaired.

Items you will need

  • Volkswagen Touareg 4.2 thermostat

  • Volkswagen Touareg 4.2 thermostat gasket

  • 10 mm wrench

 How to Change a Thermostat in a 2000 VW Jetta 2.0L

Remove the thermostat housing from the intake manifold by removing the two bolts that hold it in place. The thermostat is under the housing. Pull up on the thermostat housing and hold the radiator hose vertical to push the coolant back into the radiator. Push the hose and the housing off to the side to access the thermostat.

Lift the thermostat out of the Jetta's intake manifold and discard it. The old thermostat will not be use again. Plug the hole in the intake manifold with a shop towel.

Scrape the old gasket material off of the machined surface on the intake manifold. Do not get any of the gasket into the intake. If this happens, the intake must be professionally flushed to prevent the silicone from blocking critical engine veins that move the fluid through the engine. Once the gasket has been scraped off brush the intake off to remove any excess gasket pieces.

Pull the shop towel out of the intake and place the new thermostat into the hole. It will sit on a machined lip that is located inside of the intake. The lip may be hidden by coolant fluid.

Place a small amount of RTV silicone around the hole on the machined surface of the intake. Allow the RTV silicone to cure for 15 minutes before moving on. This will allow the RTV to "skin over" and promote a better seal between the thermostat housing and the intake manifold.

Place the thermostat housing back onto the intake manifold and bolt it into place. Start the engine and check for leaks. If there are any leaks, slowly tighten down the thermostat housing until the leaks stop.

Items you will need

  • 2000 Volkswagen Jetta 2.0-liter thermostat

  • RTV silicone

  • Shop towel

  • Scraper

  • Wrench

About the Author

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