Audi Turbo Repair and Rebuild

An Audi turbo problem starts with one fact you already know: whether the car runs on petrol or diesel. That fact separates two turbocharger designs that share no parts, and the tables below take you from there to the page for your car.

Find Your Audi Turbo: Model, Engine and Page

Three facts take you from “Audi turbo” to the right page, and the first two need nothing more than your logbook.

1. The fuel. Section P.3 of your V5C gives the fuel type. It decides which of the two tables below applies, and nothing listed in one of them fits a car in the other.
2. The model and its years. The petrol listings are divided by model generation, so an A4 built in 2002 and one built in 2010 go to different pages. The diesel listings are divided by model and engine size, so an A3 1.6 TDI and an A3 2.0 TDI each have their own.
3. The label on the turbocharger. Once the unit is off, the reference on its housing confirms which turbo you have. Photograph it before anything is packed. If it is missing or unreadable, send the unit anyway: we identify every turbo on the bench before any work starts.

Where your car’s years fall inside two listings, as a 2003 to 2006 A3 does, either listing reaches the same bench. The work is done on the unit you send, not on the description you ordered from.

Petrol or Diesel: Why the Split Matters First

Audi’s petrol and diesel turbochargers do the same job by different means, so they wear in different places and never swap.

The petrol cars run BorgWarner K03 and K04 turbochargers: one design family built in two sizes, with journal bearings fed by engine oil and a wastegate flap that lets exhaust gas bypass the turbine to hold boost at its target. What wears is the bearing system, the oil seals at each end of the shaft, and the wastegate’s pivot and linkage. On the A4 B7 2.0 TFSI the turbo comes off as one assembly with the exhaust manifold, the wastegate actuator and the diverter valve.

The TDI diesels run variable-geometry turbochargers, and our listings name Garrett and BorgWarner as the makers. Instead of a wastegate, a ring of vanes around the turbine wheel opens and closes to control boost across the rev range. Soot and oil residue bake onto those vanes until the ring stiffens, and the engine management logs a boost fault while the rotating assembly may still be sound. Depending on the engine, the vanes are moved by a vacuum actuator or an electronic one, and on the 2.7 and 3.0 V6 TDI the electronic actuator is repaired as a part in its own right.

The split also decides how far you have to go to identify the unit. On the petrol side the model generation leads straight to a listing, because each listing covers one turbo family. On the diesel side one model can span several engines: the A3 2.0 TDI listing catalogues 44 turbocharger part numbers across Pumpe-Düse and common-rail engines, and the A4 2.0 TDI listing 33. That is why the TDI listings ask for your year and power output, and why the label on the unit has the last word.

The TFSI and 1.8T Turbochargers We Rebuild

Each petrol listing below is a rebuild of the turbocharger you send in; nothing is exchanged. The right-hand notes carry the detail most likely to send you to the wrong page.

How the K03 and K04 are built, what fails on them and how we rebuild them is set out on our BorgWarner K03 and K04 page. If the fault sits in the wastegate can rather than the turbocharger, our wastegate actuator repair page explains why the setting of the rod matters as much as the part.

Petrol Audis not in this table, including the later TFSI engines, can still be sent in; the section on sending your turbo in explains how.

The TDI Turbochargers and Actuators We Rebuild

The diesel listings are sorted by model and engine size. On each one you choose your year and power output, and the listing’s part-number table shows which turbochargers are catalogued for your car. The count below is how many part numbers each listing carries, which is a fair guide to how much the label will matter.

The A4 1.9 and 2.0 TDI

Our Audi A4 TDI page covers the A4’s diesel turbochargers in depth, including the older 1.9 TDI and what a particulate filter downstream of the turbine does to a 2.0 TDI turbo. Start there if you drive a diesel A4 and want to understand the fault before you order.

The 2.7 and 3.0 V6 TDI: check the actuator first

On the V6 TDI in the A4, A5, A6 and Q7, an electronic actuator sets the position of the turbine vanes. When it fails, the car loses power or drops into limp mode while the turbocharger itself can be perfectly sound, and we rebuild the actuator on its own from £100 + VAT. Our Audi 2.7 and 3.0 V6 TDI actuator page sets out which unit each engine carries. The same 3.0 V6 is fitted to the VW Touareg, and every other car we repair actuators for is on our electronic turbo actuator repairs list.

The same engines under a VW badge

Audi’s four-cylinder TDIs are shared across the group. The A3 2.0 TDI listing includes engine codes such as BKD, BMM and CBAB that also appear in the VW Golf, where the 2.0 TDI changed from Pumpe-Düse to common rail at the same power output. Our VW Golf TDI page explains how to tell the two apart, and the same engine-code check works on an A3.

How to Send Your Audi Turbo In

The route is the same whichever table your car is in, and it works just as well for an Audi that is in neither.

1. Tell us about the car. Order the rebuild on your car’s listing, or complete the online Repair Form with the registration, the engine code if you have it, any fault codes you have read and a photograph of the turbo’s label. For a model not in the tables above, the form is the way in: give us the reference from the label and we can advise before you post anything.
2. Send it complete. On a petrol car, leave the wastegate actuator and linkage attached; an A4 B7 2.0 TFSI unit comes as the whole assembly. On a TDI, send the turbocharger with its actuator attached. If only the electronic actuator is being repaired, the actuator alone comes to us.
3. Pack it well. Seal every oil and air opening, pack the unit in a rigid box so nothing can move, and put a note inside with your name, the car and the symptom. Our FAQs cover packing and postage.
4. Post it to the workshop at Unit 102 Reaver House, 12 East Street, Epsom, Surrey, KT17 1HX, United Kingdom.
5. We strip, measure and report. The unit is checked against your engine, and if anything does not agree, we contact you before work starts. It is then rebuilt, balanced and bench-tested, typically within one to three working days of arriving.
6. Refit it with the cause put right. Fresh oil and filter, new oil feed and return lines, clean charge pipework and a primed oil feed before the engine fires. Our guide to removing, refitting and priming a turbocharger takes you through the refit.

Independent garages and main dealers use the same service for their customers’ cars, and every rebuild carries a lifetime, unlimited-mileage warranty, with no mileage cap and no time limit.

Audi Turbo Repair FAQ

Final Thoughts

“Audi turbo” is two searches wearing one name. The petrol cars share one turbocharger family, and their model generation finds the listing; the TDIs spread across dozens of references, and need their year, output and label to narrow them down. Knowing which side you are on is the first step, and it takes a glance at the logbook.

After that, the order of work matters more than the choice of page. Find what starved, clogged or overran the old unit and put it right on the car, then send us the turbocharger that came off it, complete and with its label photographed.