Automatic air temperature control (Audi 80 B3)

1. On some models, the air intake has an automatic temperature control system that is controlled by vacuum on carbureted and RM models, or a wax container on all other fuel-injected models. A flap in the air intake directs warm air from the exhaust manifold, or cool air from the atmosphere, depending on the air temperature.

2. To check the temperature control system on carbureted and RM engines, disconnect the regulator hose from the adapter in the brake booster hose and plug the adapter. Start the engine (cold) and let it run at high idle for a few minutes. Remove the air cleaner cover, reconnect the regulator hose to the adapter - the control flap should move to the fully open position, allowing only warm air to pass through. If the flap remains closed, connect a hose from the adapter to the vacuum chamber - the flap should now open. If so, the temperature control valve in the air cleaner is faulty, but if the flap remains stationary, the vacuum chamber is faulty.

3. On all other fuel-injected engines, the control flap must be removed to check the operation. Unscrew the screws and remove the unit from the air filter housing. Lower the unit in water with a temperature below 30°C, the flap should move to the position of warm air passage. Heat the water to a temperature above 38°C, the flap should close the warm air channel. If necessary, the intake air temperature control unit can be removed by disconnecting the flap and pushing the unit out through the suspension.

4. On all models, check that the flap moves freely.

This article was previously published on the resource: AUDIMANUAL.ru