Audi A6: Timing belt, tensioner or water pump failure destroying valves (1.8T 20v, 2.4/2.8 30v V6, 2.7T biturbo)
Timing belt, tensioner or water pump failure destroying valves (1.8T 20v, 2.4/2.8 30v V6, 2.7T biturbo) is a common engine fault on the Audi A6 on the 1997–2004 cars, and we rate it critical. Putting it right costs $1,100 to $7,000 at New Zealand independent workshop rates. 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 34 documented faults on the Audi A6.
- Vehicle
- Audi A6
- Only on
- Bi-Turbo / twin-turbo
- Engine
- 1.8L / 2.4L / 2.8L / 2.7L
- Years
- 1997–2004
- Fuel
- petrol
- System
- Engine
What you are looking at
No photograph available
What goes wrong
Every C5 A6 petrol engine is an interference design, so if the timing belt snaps or its tensioner or idler bearing seizes, the pistons hit the valves and the head is wrecked. Tensioner and idler failures are as common as the belt itself, and the V6 water pump (driven by the belt, with early plastic impellers) also takes the belt out when it fails. The belt should be done around every 90,000 to 120,000 km or 5 years with tensioner, idlers and water pump; many cheap C5s are overdue because the V6 job needs the front of the car put into the service position.
What you would notice
- Whine, chirp or rattle from the front of the engine that rises with revs
- Coolant weeping from behind the timing cover on V6 engines
- Engine suddenly cuts out and will not restart, cranking sounds fast and even
How to check it
Where to look. Front of the engine behind the plastic timing covers, behind the radiator and lock carrier
Ask for a dated invoice showing the timing belt, tensioner, idlers and water pump were replaced, with the odometer reading; a sticker in the engine bay alone is not proof.
If there is no record within the last 90,000 km or 5 years, budget for it straight away.
Listen at the front of the engine at idle with the bonnet open for whine, chirp or rattle.
Check the coolant level in the expansion tank and look for pink or crusty coolant stains around the front of the engine.
If a workshop inspection is possible: have the upper timing cover removed to check belt condition, date marks and tensioner play.
What it costs to put right
$1,100 to $7,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “When was the timing belt last replaced, at what km, and do you have the invoice?”
- “Were the tensioner, idlers and water pump replaced at the same time?”
- “Who did the work, an Audi specialist or a general garage?”
Now check the Audi A6 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 has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.
Where this comes from
- Blau Parts: Audi A4 A6 Timing Belt Replacement Info 2.8L 30V
- Blau Parts: Audi A6 Allroad S4 Timing Belt Replacement Info 2.7T 30V
- Blau Parts: Audi A4 Timing Belt Replacement Technical Info 1.8T
- Pelican Parts tech article: Audi A4 1.8T Timing Belt Replacement
- Classic Car Reviews: Audi A6 (C5) Saloon 1997-2004 review and buying guide
Audi A6 buyer questions
Is timing belt, tensioner or water pump failure destroying valves (1.8t 20v, 2.4/2.8 30v v6, 2.7t biturbo) serious on a Audi A6?
We rate it critical and common on the Audi A6. Every C5 A6 petrol engine is an interference design, so if the timing belt snaps or its tensioner or idler bearing seizes, the pistons hit the valves and the head is wrecked. Tensioner and idler failures are as common as the belt itself, and the V6 water pump (driven by the belt, with early plastic impellers) also takes the belt out when it fails. The belt should be done around every 90,000 to 120,000 km or 5 years with tensioner, idlers and water pump; many cheap C5s are overdue because the V6 job needs the front of the car put into the service position.
How much does it cost to fix on a Audi A6?
$1,100 to $7,000 at New Zealand independent workshop rates. 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 A6 years are affected?
Our research records this fault on the 1997–2004 Audi A6. 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?
Ask for a dated invoice showing the timing belt, tensioner, idlers and water pump were replaced, with the odometer reading; a sticker in the engine bay alone is not proof. If there is no record within the last 90,000 km or 5 years, budget for it straight away. Listen at the front of the engine at idle with the bonnet open for whine, chirp or rattle. Check the coolant level in the expansion tank and look for pink or crusty coolant stains around the front of the engine. If a workshop inspection is possible: have the upper timing cover removed to check belt condition, date marks and tensioner play. Look here: Front of the engine behind the plastic timing covers, behind the radiator and lock carrier