What is the reason for the Passat's heater not getting hot?
2 Answers
Passat's heater not getting hot is caused by the malfunction of the heater control mechanism. Check whether the temperature of the two inlet pipes of the heater small tank is normal. The solutions and reasons for the heater not getting hot are as follows: Reasons: The malfunction of the heater control mechanism leads to the issue. The temperature of the two inlet pipes of the heater small tank should be checked. The structure of the heater small tank is essentially a scaled-down version of the engine radiator, with multiple small cooling pipes inside. Like the radiator, it is prone to internal clogging. Check whether the engine water temperature is normal. If it remains at a low temperature, the heater will definitely not get hot. Repair or replace the faulty component to resolve the issue.
I've been driving a Passat for several years, and the most common issue with the heater not blowing hot air is insufficient or leaking coolant. The coolant is responsible for transferring heat from the engine to the heating system; if there's too little, it won't blow hot air. Additionally, check the thermostat, which controls the engine's warm-up. If it's stuck in the closed position, the engine won't reach the proper temperature, and the heater will naturally blow cold air. A clogged heater core is also a big deal—debris blocking it prevents hot air from passing through. There might also be a fault with the air flap control, where the adjustment plate is in the wrong position, blowing cold air. I've noticed that poor maintenance often leads to these issues. Regularly changing the coolant and inspecting the pipes can prevent them. It's particularly frustrating when the heater doesn't blow hot air right after starting the car in winter. Quickly take it to a repair shop to avoid turning it into a major engine problem, which can be costly to fix. These methods apply to the Volkswagen series, and I've checked them several times with good results.
