Lexus GS engines – Timing belt or chain?

Generations

Lexus GS (L10) 4th generation (2011-)

Lexus GS (S190) 3th generation (2005 – 2011)

Lexus GS (S160) 2th generation (1997 – 2004)

Lexus GS (S140) 1th generation (1993 – 1997)

Related: Lexus / all car manufacturer