The timing belt sometimes referred to as the timing chain, is an integral part of the internal combustion engine. It is responsible for synchronizing the rotation of the crankshaft and the camshaft to ensure that the valves open and close on the engine. Without proper timing, it can lead to misfires as well as other problems. How the Timing ... Mar 02, 2018 · The 2008 GS 350 is a 6 cylinder and has a timing chain and does not require replacement. The 2006 GS 430 and all other 8 Cyl 4.3slike the SC, LS etc have an actual Belt. I just replaced mine at 150,000 Klms. It was still in perfect shape. The water pump was pristine but I replaced it too while I was in there.
In September 2005, the GS 350 (GRS191) and GS 430 (UZS190) went on sale in Japan; the GS 350 using a 3.5-liter 2GR-FSE engine with D4-S direct injection, while the GS 430 used the same 4.3-liter 3UZ-FE V8 engine used in the previous model. For the 2007 model year, the GS 350 replaced the GS 300 in the US and several other export markets.