Thermostat and cooling system Audi: problems by model and engine

Documented faults, from most to least important

Severity × frequency. Below each one, the Audi models it appears in.

- High severityFrequency: Common3.0 TDI V6Failing water pump and cooling system leaksOn the 3.0 TDI the water pump can fail and, from 2010, overheat to the point of damaging the engine (the A6 C6 guide cites a service action). Owners also cite coolant leaks from hoses, the regulating valve and the cooler.
In A4 B7, A4 B8, A4 B9, A5 I, A5 II and A6 C6 and 12 more models
- Medium severityFrequency: Common2.0 TSI / TFSIThermostat housing leak and water pump failureSince Volkswagen integrated the water pump impeller into the thermostat housing, this plastic part leaks coolant over time; on the oldest units, with a separate belt-driven pump, failures of the pump itself are also documented.
In A3 II, A3 III, A3 IV, A4 B8, A4 B9 and A5 I and 6 more models
- Medium severityFrequency: Common2.0 TDICoolant loss from the water pump or the coolersMany 2.0 TDI engines lose coolant. On the 150 hp EA288 the water pump is usually the culprit and, more rarely, the cylinder head; on the 140 hp EA189 the typical causes are the oil cooler or the EGR cooler.
In A3 II, A3 III, A4 B8, A4 B9, A6 C7 and Q2 and 2 more models
- Medium severityFrequency: Common1.2 and 1.4 TSIWater pump and thermostat housing leak (EA211)On the 1.2 and 1.4 TSI EA211 the water pump is integrated into the plastic thermostat housing; over the years it can crack or lose its seal and the engine slowly loses coolant. Caught in time, it does not damage the engine.Appears at around 80,000 km
In A1 I and A3 III
- Medium severityFrequency: OccasionalAudi 3.0 TFSI V6Leak at the thermostat housing and water pumpTechnical guides cite coolant leaks from the plastic thermostat housing and from the water pump of the supercharged 3.0 TFSI, and Audi also replaced the thermostat in a 2015 campaign. You notice it by falling coolant and, if ignored, by overheating.
In A4 B8, A5 I, A6 C6, A6 C7, A7 C7 and A8 D4 and 3 more models
- Medium severityFrequency: Occasional1.0 TSI / 1.5 TSICoolant leaks from the water pump and thermostat moduleOn the EA211 the water pump and thermostat housing form a plastic module that, over the years, can crack or lose its seal and cause a slow loss of coolant. Keep an eye on the level: if it is ignored, it can end in overheating.
In A1 I, A1 II, A3 III, A3 IV, Q2 and Q3 II

By Audi model

Open yours to see only the faults that affect it, by engine and by year.

Engines and gearboxes involved

Frequently asked questions

What faults with the thermostat and cooling system do Audi cars have?

In 28 models from Audi there are 6 documented faults with the thermostat and cooling system. The most important: failing water pump and cooling system leaks, thermostat housing leak and water pump failure and coolant loss from the water pump or the coolers. Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

Which Audi models have the most problems with the thermostat and cooling system?

Audi A4 B8 (4 faults), Audi Q5 I (4 faults), Audi A3 III (4 faults) and Audi A5 I (3 faults).

Which Audi engines have faults with the thermostat and cooling system?

1.0 TSI / 1.5 TSI (1 fault), 1.2 and 1.4 TSI (1 fault), 2.0 TDI (1 fault), 2.0 TSI / TFSI (1 fault) and 3.0 TDI V6 (1 fault).