Free guide · 1997–2002 · 2.7 V6 biturbo · 265 PS
Audi S4 B5: what to check before you buy
What this car is, and the six questions that decide whether the one you are looking at is a good buy.
In this guide · 6 chapters
Who built it, and what they built
The B5 S4 put a 2.7-litre twin-turbo V6, a six-speed manual and quattro into Audi's compact saloon and estate — and it did so with an engine that a whole tuning culture was subsequently built on.
The 2.7T is a 2,671 cc V6 with two turbochargers: engine codes AGB and AZB in Europe, with 265 PS, and APB in North America, with 250 PS. Built from late 1997 to 2001; the last North American cars were sold as 2002 models. Six-speed manual, or the five-speed tiptronic automatic.
Two turbochargers and a manual gearbox, in a compact saloon or estate, with four-wheel drive. That combination is why people still want one, and why the ones that survive are the ones whose owners understood what they had.
And yes, it has turbochargers
This series is about the last generation of cars built with an engine somebody thought about, and the criterion is six cylinders or more with real character — not naturally aspirated. A 2.7 V6 with two turbos, a manual and quattro belongs here as much as any atmospheric V8. What it does not have is the tolerance for neglect that some of those V8s have, and that is what this guide is about.
One piece of genuinely good news, before the rest
The main camshaft drive is a belt.
On most cars in this series the timing drive is a chain you cannot inspect and cannot schedule — you find out about it when it fails. Here the crankshaft drives the camshafts through a belt, which means an interval, an invoice, and a date. (Each head also has a short camshaft chain, which the buying guide covers.) It is the one major item where a single dated invoice settles the question.
Keep that in mind, because everything else in this guide comes down to whether the previous owner cared.
How the figures in this guide work
No euro totals: a labour rate differs by country and by workshop. Each job carries a step on a scale of five — an hour or two, half a day, a day, two or three days, a week or more in the workshop — plus one line on where the work sits.
The six questions that decide whether this car is a good buy
1 · Where are the oil change invoices?
Not "has it been serviced". The invoices, with mileages. On this engine that is not paperwork diligence — it is the mechanical condition, and the buying guide explains exactly why.
2 · When was the timing belt done, and with the water pump and rollers?
A belt is an interval. Ask for the invoice and the mileage on it.
3 · Does it make the boost it asks for?
There are two turbochargers, and a shortfall in boost is worth finding before you make an offer; whether it is a hose or a turbocharger is a job for the workshop. How to have it measured, and what that measurement can and cannot tell you on this engine, is in the buying guide.
4 · Does it misfire — and on which cylinders?
A misfire leaves a record in the fault memory. Knowing which cylinders it names is worth having before you start replacing coil packs, plugs or the wiring harness — and what that record can and cannot tell you is in the buying guide.
5 · Has anyone looked at the cam-chain tensioners?
Separate from the belt: a short camshaft chain in each head, with hydraulic tensioners on plastic pads. They wear, especially where the oil has been neglected.
6 · Are you buying this as a second car or as a daily one?
Asked of yourself, not the seller. One buying guide is blunt that it is a fine second car and a poor daily one unless you have deep pockets. That is worth hearing before you fall for one.
What the honest answer to all six looks like
A folder of oil invoices, a dated belt service and a clean charge-pressure log is a car you can buy with confidence — and those cars exist, because the people who kept these cars alive are exactly the people who kept the receipts. A tidy 2.7T with no service history is not a bargain in disguise. Our own research block puts it as plainly as it can be put: without the paperwork, walk away.
Which years, which specification
Built from late 1997 to 2001; the last North American cars were sold as 2002 models. Engine codes AGB and AZB (Europe, 265 PS) and APB (North America, 250 PS), all 2.7 litres.
Saloon or Avant, and both are this car. (The RS4 B5 is a different animal with a different engine specification — do not read across.)
Six-speed manual or five-speed tiptronic. The tiptronic changes the character of the car substantially.
What matters far more than any of the above: the K03 turbochargers are small, and the tuning culture that grew around this engine means a lot of these cars have been modified. That is not automatically bad — but it changes what you are inspecting. A modified 2.7T with a folder of invoices from a specialist is a known quantity. A modified 2.7T with a remap of unknown origin and no history is not a car, it is a lottery ticket.
Ask what has been changed, ask who did it, and ask for the invoices. The same rule as the oil.
What it is worth
No price list — it moves by country and by month. On this car the method is unusually simple to state, and unusually strict.
The paperwork is not evidence about the car. It is the car.
That sounds like a slogan. The buying guide sets it out: neglected oil on a 2.7T — changed late, or the wrong oil — can damage three separate things: the turbocharger bearings, the sump, and the plastic pads in the cam-chain tensioners. So a car with documented oil changes has ruled out the cause the three have in common, and a car without them leaves it open. There is no inspection that recovers that information after the fact.
Which gives you two kinds of car and not three.
The documented car. Oil invoices, a dated belt service, ideally a specialist's name recurring in the folder. Pay the premium.
The undocumented car. However nice it looks and however well it drives. Our block's advice is to walk away, and this guide is not going to soften it — because the failure mode here is not a repair you can price, it is a range that runs from a cleaning job to a rebuilt engine.
Compare entry prices, not asking prices — and on this model, treat an absent folder as an entry price you cannot calculate.
What it is actually like to own one
Two turbochargers, a manual gearbox, four-wheel drive, and a shape that has aged better than almost anything from 1998. The 2.7T is also endlessly tuneable, which is why it has the following it does.
And now the honest part, because a guide that only sells you the good bits is not worth paying for. One published buying guide's summary is that this is a great second car and a bad choice for a daily driver unless you have deep pockets.
That is not a reason to avoid one. It is the expectation you should have. The cars that survive in good order are owned by people who service them ahead of schedule and keep the receipts, and there is a reason those two habits go together on this engine specifically.
The habits that decide everything, and they are cheap:
- oil, on time, every time, with the right specification. This is the whole ownership in one line.
- have the charge pressure logged occasionally rather than waiting for limp mode
- treat the belt as a date, and do the water pump and rollers with it
What surprises people is how much of this car's fate is decided by the previous owner rather than by the engineering. The 2.7T is not fragile. It is unforgiving of neglect, which is a different thing — and it means your job as a buyer is mostly reading, not listening.
The buying guide — €24
Everything above is what the car is. This is what you check.
Eight faults that belong to this engine, taken apart one by one, with how much work each repair is and how to tell which of them you are looking at. Eight things that are simply twenty-five years old, every one with how much work it is, what tells you about it at a viewing, and whether it has to be done now, within a year or two, or not at all. Why the bodyshell is a short chapter, and what to add on an Avant. Why neglected oil on this engine can produce three separate bills. The viewing in six steps, including the two moments that come only once. The sentences you say to the seller, and how to build an offer out of what you found.
And a card you print and take with you — twenty lines, in the order you do them. That comes as a separate file, because nobody wants to print a whole guide to take a few pages to a car park.
This is what one of the eight looks like
6 · Valve cover gaskets
Half a day · access Ordinary age. Worth doing so that the next leak is traceable.
And this is how the card reads
- 1 · The paperwork · FIRST. If this fails, stop.
- 2 · The cold start
- 3 · The engine bay, engine off
- 4 · The read-out · before the test drive
- 5 · The test drive
- 6 · Underneath
What €24 buys, put next to what it saves
Neglected oil can take the turbo bearings, the sludge in the sump and the plastic pads in the cam-chain tensioners — three bills from one omission, and the worst case is a week or more in the workshop. The paperwork is the whole purchase here. The guide is €24. It will not stop any of that from being needed — but it does tell you which of them you are looking at before you agree a price, and that is the whole of the difference between paying for a car and paying for someone else's postponed maintenance.
Why there are no prices in it
Because a price we cannot verify is worse than no price, and because a price would be wrong for most of the people reading this anyway. Workshop rates across Europe differ widely, and so do parts prices. A quote from a specialist in one country tells you nothing in another.
What does not change is how much work a job is — that follows from what has to come off the car. So every point in the guide says whether it is an hour or two, half a day, a day, two or three days, or a week or more in the workshop, with a labour figure where a source gives one. And it says whether the money sits in the part or in getting to it, which is what lets you tell a fair quote from a bad one.
If you want a figure, ask any workshop one question — what is your hourly rate? — and every effort level in the guide becomes your own number, in your own currency. One question, and the answer is actually true for you.
How this guide was put together
Because you should know before you pay for it.
- Every fault and symptom comes from a source the guide names, the manufacturer's own documents first. The effort levels are our assessment, unless a source gives the hours.
- One buying guide says outright that this is a fine second car and a poor daily one unless you have deep pockets. The guide passes that on rather than selling you a fantasy.
- The effort of every job is counted item by item and checked against the list before every edition.
- It says as plainly what you can leave alone as what you have to do. None of the eight age points start from leave it.
Leave your email address at the checkout and both files arrive straight away: one guide and one card, as two pdfs. No subscription, no account.
The full guide · €24
17-page guide, A4 and phone · 3-page inspection card · instant PDF · VAT included
Have every car inspected before you buy by someone who knows this engine. This is general information about the model and not advice about a specific car.