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Audi A4: Water pump internal seal failure, coolant into vacuum system (3.0 TFSI EA839 V6 turbo, B9 A4 and S4)

Water pump internal seal failure, coolant into vacuum system (3.0 TFSI EA839 V6 turbo, B9 A4 and S4) is a common cooling fault on the Audi A4 on the 2017–2024 cars, and we rate it major. Putting it right costs ≈A$1,840 to ≈A$4,140 at independent workshop rates, shown as an approximate guide in Australian dollars. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 46 documented faults on the Audi A4.

Vehicle
Audi A4
Engine
3.0L
Years
2017–2024
Fuel
petrol
System
Cooling

This page covers the Audi A4 as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Audi A4 faults46 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Water pump or Turbocharger yet. We would rather show none than show a picture of a different part.

What goes wrong

The 3.0 TFSI EA839 turbo V6 used in the B9 A4 family (sold as the S4) has a water pump and coolant module whose seals and internals wear out early. Coolant can weep from the pump and can also be drawn into the vacuum system, so the car may lose coolant with nothing on the ground. Ignored, it can lead to overheating and wider damage. Audi released an improved pump (6-bolt pulley instead of 4-bolt) and the fault is the subject of a US class action covering 2018 to 2024 2.9 and 3.0 V6 models; there is no Australian recall. This does not apply to 2.0 TFSI or diesel A4s.

What you would notice

  • Coolant level keeps dropping with no visible leak
  • Low coolant or overheat warning
  • Drivetrain Malfunction warning with reduced power
  • Pink or purple crusty residue on the front of the engine

How to check it

Where to look. Front of the engine, water pump and coolant module behind the drive belt

With the engine cold, check the coolant expansion tank is at the correct level and not freshly topped up. Use a phone torch to look at the front of the engine around the water pump for pink or purple crusty coolant residue. Ask whether the water pump has been replaced and look for an invoice. On the test drive watch for coolant, overheat or Drivetrain Malfunction warnings. If a workshop inspection is possible: check whether the water pump pulley has 6 bolts (updated part) or 4 bolts (original), pressure test the cooling system, scan for P0299 and coolant fault codes, and check vacuum lines for coolant contamination.

Parts involved: Water pump, Turbocharger.

What it costs to put right

≈A$1,840 to ≈A$4,140 at independent workshop rates, shown as an approximate guide in Australian dollars. That is for this job on its own, not for the car.

An estimate, converted to Australian dollars, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Has the water pump been replaced, and do you have the invoice?”
  • “Do you have to top up the coolant between services?”
  • “Has the car ever shown a Drivetrain Malfunction or overheat warning?”

Now check the Audi A4 you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car still has money owing on it, has been written off or reported stolen, what kms it showed in past sale ads, whether it has had accident repair claims and what it is worth today. That comes from the official records for that plate. Enter the plate and its state for the A$17.90 Vehicle Check, or the full history from A$24.99.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

Audi A4 buyer questions

Is water pump internal seal failure, coolant into vacuum system (3.0 tfsi ea839 v6 turbo, b9 a4 and s4) serious on a Audi A4?

We rate it major and common on the Audi A4. The 3.0 TFSI EA839 turbo V6 used in the B9 A4 family (sold as the S4) has a water pump and coolant module whose seals and internals wear out early. Coolant can weep from the pump and can also be drawn into the vacuum system, so the car may lose coolant with nothing on the ground. Ignored, it can lead to overheating and wider damage. Audi released an improved pump (6-bolt pulley instead of 4-bolt) and the fault is the subject of a US class action covering 2018 to 2024 2.9 and 3.0 V6 models; there is no Australian recall. This does not apply to 2.0 TFSI or diesel A4s.

How much does it cost to fix on a Audi A4?

≈A$1,840 to ≈A$4,140 at independent workshop rates, shown as an approximate guide in Australian dollars. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Audi A4 years are affected?

Our research records this fault on the 2017–2024 Audi A4. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

With the engine cold, check the coolant expansion tank is at the correct level and not freshly topped up. Use a phone torch to look at the front of the engine around the water pump for pink or purple crusty coolant residue. Ask whether the water pump has been replaced and look for an invoice. On the test drive watch for coolant, overheat or Drivetrain Malfunction warnings. If a workshop inspection is possible: check whether the water pump pulley has 6 bolts (updated part) or 4 bolts (original), pressure test the cooling system, scan for P0299 and coolant fault codes, and check vacuum lines for coolant contamination. Look here: Front of the engine, water pump and coolant module behind the drive belt