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1.6 THP vs 1.8 T 20v: which engine is more reliable?

According to our risk index, the 1.8 T 20v carries less risk than the 1.6 THP: 32/100 (moderate risk) versus 64/100 (high risk). The 1.6 THP has 2 documented serious faults, the main one being «Timing chain and tensioner stretch (turbo versions, before 2012)»; the 1.8 T 20v has 1 documented serious fault, the main one being «Turbo wear and oil consumption».

Risk index

1.6 THP

64

High risk · 2 serious faults

Risk index

1.8 T 20v

32

Moderate risk · 1 serious fault

Lower risk

The index (0–100) weights the severity and frequency of the three most serious documented faults. How it is calculated

17 sourcesHow we work

Is the 1.6 THP reliable?

The 1.6 THP turbo and its naturally aspirated sibling, the 1.6 VTi, make up the Prince family, developed together with BMW and also used by MINI: they do not have a reputation for reliability. Turbo versions built before 2012 carry a known problem of timing chain stretch, and the whole block shares a water pump described as fragile; the turbo versions add oil consumption and high-pressure fuel pump failures.[1][2][3][4]

See the 5 of the 1.6 THP faults

Is the 1.8 T 20v reliable?

With up-to-date maintenance, the 20-valve 1.8T has a reputation as a powerful, durable engine for its time, but owner reports document recurring faults: ignition coils (especially on 2001 to 2003 units), water pump and air mass meter, and less often the turbo -sometimes linked to growing oil consumption- and the timing chain tensioner.[5][6][7][8][9][10]

See the 5 of the 1.8 T 20v faults

Side-by-side comparison

Comparison of 1.6 THP and 1.8 T 20v
1.6 THP1.8 T 20v
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement1,598 cm³1,781 cm³
TimingChainTiming belt (dry)
Power120–270 hp150–225 hp
Production2006–2018[1][11][12]1996–2006[13][14][15][16]
Reliability
Risk index (what is it?)64High risk32Moderate risk
Documented faults55
Of high or critical severity21
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: Timing chain and tensioner stretch (turbo versions, before 2012)
  2. High severity: Fragile water pump and heat exchanger
  3. Medium severity: High-pressure fuel pump (HPFP) failure on the turbo versions
  1. High severity: Turbo wear and oil consumption
  2. Medium severity: Water pump failure
  3. Medium severity: Timing chain tensioner noise and wear
Most expensive documented repairNo reliable dataNo reliable data
Which versions to buy
BuyRecommended versionsNoneNone
With cautionVersions to be cautious about
  • 1.6 VTi 120 / 1.6 16v (EP6/EP6C, N12/N16, naturally aspirated)[4]
  • 1.6 THP medium output (EP6DT/EP6DTS/EP6CDT, N14/N18; 140-190 hp)[2][3][17]
  • 1.6 THP high performance (EP6CDXD/EP6FDTR/EP6CDTR, John Cooper Works N14/N18; 200-270 hp)[2][3][4]
  • 1.8 T 20v 150 hp (AEB/AGU/ARZ/AUM, 1996-2005)[6][10]
  • 1.8 T 20v 180 hp (AUQ, 1998-2006)[7][8]
  • 1.8 T 20v 225 hp quattro (BAM, 1999-2006)[8]
AvoidVersions to avoidNoneNone

Severity of each fault: green, low; amber, medium; red, high; dark red, critical. How we rate them

Cars that each one is fitted to

1.6 THP

See the 16 models with the 1.6 THP

1.8 T 20v

See the 11 models with the 1.8 T 20v

Other comparisons

With the 1.6 THP

With the 1.8 T 20v

Compare other engines

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Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Prince engineWikipedia (inglés) · Other source · consulted 27 September 2026
  2. Distribution : les moteurs à problèmesFiches-auto.fr · Motoring press · published April 2025 · consulted 27 September 2026 · in French
  3. Moteurs essence qui consomment de l'huileFiches-auto.fr · Motoring press · published April 2024 · consulted 27 September 2026 · in French
  4. Liste des moteurs qui ont des soucis de refroidissementFiches-auto.fr · Motoring press · published April 2025 · consulted 27 September 2026 · in French
  5. Fiabilité et pannes Volkswagen Golf IVFiches-auto.fr · Other source · consulted 27 September 2026 · in French
  6. Fiabilité et pannes Volkswagen PassatFiches-auto.fr · Other source · consulted 27 September 2026 · in French
  7. Fiabilité et pannes Audi A3Fiches-auto.fr · Other source · consulted 27 September 2026 · in French
  8. Fiabilité et pannes Audi TTFiches-auto.fr · Other source · consulted 27 September 2026 · in French
  9. Fiabilité et pannes Seat LeónFiches-auto.fr · Other source · consulted 27 September 2026 · in French
  10. Seat Leon Mk1: Probleme, Schwachstellen, ErfahrungenGebrauchtwagenberater.de · Other source · consulted 27 September 2026 · in German
  11. Peugeot 308Wikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
  12. Peugeot RCZWikipedia (inglés) · Other source · consulted 27 September 2026
  13. List of Volkswagen Group petrol enginesWikipedia · Other source · consulted 27 September 2026
  14. Audi TTWikipedia · Other source · consulted 27 September 2026
  15. SEAT LeónWikipedia · Other source · consulted 27 September 2026
  16. SEAT ToledoWikipedia · Other source · consulted 27 September 2026
  17. BMW Recalls Fuel Pumps. Mini Does NotMotoringFile · Motoring press · published 27 October 2010 · consulted 27 September 2026