Genuine Volkswagen GTI Thermostat

Volkswagen GTI Thermostat Parts and Q&A

• Thermostat
  06L-121-111-P
  Q: What are the precautions and steps for replacing a thermostat on Volkswagen GTI?

  A:

  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.