Is the Thermostat of Nissan Sylphy Located on the Upper or Lower Hose?
2 Answers
The thermostat of the Nissan Sylphy is located at the connection point between the lower hose and the engine block. The thermostat is a valve that controls the flow path of the coolant, functioning as an automatic temperature-regulating device. It typically contains a temperature-sensitive component that opens or closes the flow of air, gas, or liquid through thermal expansion or contraction. The steps for replacing the thermostat are as follows: 1. Turn off the engine, open the front hood, disconnect the negative terminal of the battery, and remove the plastic cover outside the timing belt; 2. The position of the generator may affect the thermostat replacement, so the generator assembly needs to be removed; 3. Place a water-catching tray under the car, then prepare to remove the hose, wait for the antifreeze to drain completely, remove the faulty thermostat, install the new thermostat, and apply a layer of sealant to the hose area after installation; 4. Reinstall the removed hose, generator, and timing plastic cover, reconnect the negative terminal of the battery, add new antifreeze, and then start the engine for testing. The Nissan Sylphy is a compact car with dimensions of 4631mm in length, 1760mm in width, and 1503mm in height, and a wheelbase of 2700mm.
I've been repairing cars for over a decade. The thermostat on the Nissan Sylphy is commonly installed on the upper radiator hose, unlike some people guess it's on the lower hose. This is because the upper hose connects to the radiator inlet, allowing it to respond faster to the engine's warming needs. The main function of the thermostat is to regulate coolant flow—it stays closed during cold starts to help the engine warm up quickly and only opens when overheating occurs to allow coolant circulation for cooling. If it fails, the engine temperature can either spike dangerously or remain too low, often triggering warning lights during highway driving. Prolonged issues may damage the engine and increase fuel consumption. I recommend regularly checking the coolant's color and level. If anything seems off, take it to a repair shop immediately for replacement. Don't delay, as replacing it requires proper coolant draining and refilling, which is a technical job.
