Description

This is a fully reconditioned Garrett GT20V turbocharger for the Audi A6 2.5 TDI V6 (AKE/AYM engine codes) produced between 1997 and 2005. As a genuine Garrett unit, reconditioned by our specialists in Birmingham, it is a direct replacement for original equipment part number 454135-5009s, restoring original performance and efficiency.

The 2.5 TDI V6 engine is generally robust, but the turbocharger is a known weak point after high mileage. The most common failure mode on this GT20V unit is seizure of the variable nozzle turbine (VNT) mechanism. Carbon and soot deposits from the exhaust, often exacerbated by short journeys or EGR system faults, cause the delicate internal vanes to stick. This prevents the turbo from regulating boost pressure correctly, leading to fault codes, the vehicle entering ‘limp mode’, and a significant loss of power. Another frequent issue is failure of the electronic actuator that controls these vanes. Over time, it can suffer from internal electronic faults or mechanical wear, resulting in similar underboost or overboost symptoms. Finally, standard wear and tear on the central bearing cartridge (CHRA) can occur due to oil contamination or starvation, leading to whining noises, smoke from the exhaust, and eventual catastrophic failure if ignored.

At Gap Turbos, our reconditioning process is comprehensive. Each turbo is completely disassembled and subjected to an intensive ultrasonic cleaning process to strip away all carbon and oil residue. Components are then inspected for wear against OE specifications. All service parts, including journal and thrust bearings, piston rings, and oil seals, are replaced with new, high-quality components. The rotating assembly is then precision balanced on our VSR (Vibration Sorting Rig) at speeds exceeding 150,000 RPM, which is critical for longevity and quiet operation. The VNT mechanism and actuator are calibrated to ensure flawless performance before the unit is dispatched.

What this turbocharger fits

This reconditioned turbocharger is a direct fit for the following vehicles:

• Make: Audi
• Model: A6 (C5)
• Engine: 2.5 TDI V6
• Engine Codes: AKE, AYM
• Power Output: 150 HP
• Years: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
• OE Part Number: 454135-5009s
• Alternative Part Number: 059145702D

We can supply this unit on an exchange basis, fit it for you in our Birmingham workshop, or provide a brand new replacement. We strongly recommend investigating the root cause of the original failure, which may involve cleaning the EGR and intake systems. Contact Gap Turbos today for a competitive quote and details of our comprehensive warranty.

Specifications

Vehicle fitment

• Audi A6 2.5 TDI V6

Common faults & troubleshooting

• Loss of power and ‘limp mode’ activation: This is the classic symptom of a seized VNT mechanism or a faulty electronic actuator, causing overboost or underboost fault codes.
• Loud whistling or siren noise from the engine: This indicates worn bearings or that the compressor/turbine wheels have been damaged by foreign object impact.
• Black smoke from the exhaust under load: While it can be injectors, this often points to a boost leak in the pipework or a turbo not producing sufficient air.
• Blue/grey smoke, especially on start-up: This is a clear sign that the turbo’s internal oil seals have failed, allowing engine oil to pass into the intake or exhaust.
• Poor fuel economy and general sluggishness: A turbo that is not operating efficiently due to wear or a VNT fault will force the engine to work harder, increasing fuel consumption.

Fitting notes for this unit

• You MUST replace the oil feed pipe and banjo bolts: The original pipe is prone to internal carbon build-up (coking) which restricts oil flow and will starve the new turbo of lubrication, causing immediate failure. Do not use any form of sealant on oil gaskets.
• Prime the turbo before starting: Before connecting the oil feed line, add clean engine oil directly into the turbo’s oil inlet port. Then, disable the fuel injectors and crank the engine for 15-20 seconds to build oil pressure and circulate oil through the new unit.
• Perform a full engine service: A complete oil and filter change using the correct OEM-specification oil is mandatory. The old oil will be contaminated from the previous turbo failure.
• Inspect the entire air intake system: Thoroughly clean the intercooler and all boost pipes to remove any oil residue or metal fragments from the previous failure. Any debris left in the system will be ingested by the new turbocharger.
• Check the exhaust system for blockages: A blocked catalytic converter or DPF can create excessive back-pressure, which puts a huge strain on the turbo’s thrust bearing and seals, leading to premature failure.

Alternative part numbers

This turbo is also referenced by:

• 059145702D — Audi Turbocharger OEM 059145702D (Audi A6 2.5 TDI V6, AKE/AYM, 150hp)

Frequently asked questions