Question 1

What are the precautions and steps for replacing a thermostat on Volkswagen Jetta?

Accepted Answer

Do not drive the vehicle without a thermostat, this may leave the computer in open loop, which adversely affects the emissions and fuel economy. In case of disconnection of the battery, a number of systems will have to be re-learned to operate correctly. The models 2.0L (CBPA) and 2.5L (CBTA, CBUA) have a bypass thermostat positioned in the top section of the bypass hose. The first stage is to take off the engine cover and unscrew the negative battery terminal. Lift the front part of the car safely on jackstands and then remove the under car splash shield. Take out the coolant in the radiator, keeping it in mind that the coolant is new or refilling it with the warning of already used antifreeze. In the case of 1.4L engines, it can be stated that two thermostats exist, one serves the main cooling circuit, and another one serves the engine block. Take out the intake air resonator, air filter housing and charge air cooler air pipe, and disconnect the coolant hose clamps and take out the hoses of the thermostat cover. Unscrew the thermostat housing clamps and take the cover off, be ready to spill with coolant. Wipe down the mating surfaces then follow with a special thermostat removal tool or snap-ring pliers and pull out the thermostat. Install a new thermostat making sure to align the centering pin, then a new gasket and the thermostat cover is to be reattached. Installation is the opposite to removal. Otherwise, replace small thermostat, fill and bleed system, then engine check. In the case of the cylinder block circuit thermostat, take off the water pump and heat exchanger connection bolts and detach the water pump and the heat exchanger assembly and take out the thermostat. Place a new thermostat in the water pump making sure that it is well aligned and then clean the mating surfaces before reassembling the thermostat cover. Repeat the refill and bleed process. In the case of the 2.0L (CBPA) engine, the thermostat housing is located below the intake manifold, and the radiator hose is disconnected, as well as the fasteners of the housing are removed. Install new O-ring and thermostat, with jiggle valve upwards. The reverse of the removal is the installation. In 1.8L and 2.0L engines, take out the water pump and throttle body, disconnect the coolant hoses, and also take out the engine temperature control actuator assembly. Cleaning of mating surfaces, installation of new O-rings and fixing of the assembly, proper alignment. The installation will be inverted and then the system will be refilled and bled. With 2.5L engines, the intake manifold, thermostat cover and seal are removed and the thermostat installed with the jiggle valve up. Insert the cover again and repeat the reverse process of installing, making sure you refill and bleed the system as well as ensuring that you do not have any leaks.

Question 2

What precautions should be taken, and How to replace a faulty thermostat on Volkswagen Passat?

Accepted Answer

Do not drive the car without a thermostat since the computer could be in open loop mode and this will adversely affect the emissions and fuel economy. The coolant level, drivebelt tension, and temperature gauge are the things to be checked before concluding that the thermostat is malfunctioning. When the engine takes long to warm up then the thermostat is probably stuck open and needs to be changed. In case the engine is hot, but the upper radiator hose is not hot, the thermostat can be stuck shut, and thus will not allow coolant to escape to the radiator, and must also be changed. When the upper radiator hose is hot this means that coolant is running and therefore the thermostat is open. With the aim of replacing the thermostat, lift the front of the vehicle and place it on jackstands, dislodge the splash shield and drain the radiator of the coolant, saving it in case it is in good condition. In the case of V6 engines, the radiator support panel should be installed in the service position. Find the thermostat housing cover by tracing the bottom of the radiator hose to the engine; on four-cylinder engines it is on the driver side of the bottom of the water pump housing and on the V6 engines, it is in the front of the engine block. Press the tabs on the hose clamp and remove the hose off the thermostat housing cover being careful not to spill the coolant onto the timing belt. The cover fitting can be worn-out and in this case, it can be replaced. Unscrew the bolts/nuts to loosen the thermostat cover, ensure the orientation of how the thermostat was installed and the cover O-ring. Wipe the mating surfaces, mount the new thermostat as in with the appropriate end of the thermostat towards the outside, and a new O-ring on top and then re-mount the thermostat housing cover. Tighten the bolts to the required torque and may think of checking and changing hoses and clamps. Lastly, reverse the unloading process, fill up and bleed the system, and start the engine and leakages.

Genuine Volkswagen Thermostat

38 Thermostats found

Volkswagen Thermostat Part Number: 7E0-820-295-B

Volkswagen Thermostat Part Number: 7B0-121-113-A

Volkswagen Thermostat Part Number: 044-121-113

Volkswagen Thermostat Part Number: 04E-121-113-G

Volkswagen Thermostat Part Number: 1K0-121-113-A

Volkswagen Thermostat Part Number: 07K-121-113-B

Volkswagen Thermostat Part Number: 04E-121-113-F

Volkswagen Thermostat Part Number: 03G-121-113

Volkswagen Thermostat Part Number: 03G-121-113-A

Volkswagen Thermostat Part Number: 06J-121-113

Volkswagen Thermostat Part Number: 077-121-113-D

Volkswagen Thermostat Part Number: 022-121-113

Volkswagen Thermostat Part Number: 03H-121-113-D

Volkswagen Thermostat Part Number: 06H-121-113-B

Volkswagen Thermostat Housing Part Number: 06F-121-111-H

Volkswagen Thermostat Part Number: 03H-121-113-E

Volkswagen Thermostat Part Number: 059-121-111-R

Volkswagen Thermostat Part Number: 06F-121-111-F

Volkswagen Thermostat Part Number: 06E-121-111-AL

Volkswagen Thermostat Part Number: 06K-121-113-G

Volkswagen Thermostat

Volkswagen Thermostat Parts and Q&A

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