Assuming that this is a US 2004 Toyota Sienna... If you go to Toyota's FAQ site, http://toyota.custhelp.com/ , and search for "timing" then you'll find this document titled "Timing Belt and Timing Chain" which lists all US sold Toyota vehicles and whether they have a timing belt or timing chain/gear: http://toyota.custhelp.com/cgi-bin/toyot... The 1998-2006 US Toyota Sienna uses a timing belt (so your Sienna has the belt, NOT the chain). 2007-2008 model years has the timing chain.
From Toyota.com:ModelYearEngineBelt/Chain/Gear4Runner1990-2000,20104 CylinderChain1990-2002V6Belt2003-2010V6Chain2003-2009V8BeltAvalon1995-2003V6Belt2004-2011V6ChainCamry1990-2001AllBelt2002-20114 CylinderChain1990-2006V6Belt2007-2011V6ChainCamry Hybrid2007-20114 CylinderChainCelica1990-19994 CylinderBelt2000-20054 CylinderChainCorolla1990-19974 CylinderBelt1998-20104 CylinderChainCressida1990-1992L6BeltECHO2000-20054 CylinderChainFJ Cruiser2007-2010V6ChainHighlander2001-2008,20104 CylinderChain2001-2007V6Belt2008-2010V6ChainHighlander Hybrid2006-2010V6BeltLand Cruiser1990-1992L6Gear1993-1997L6Chain1998-2007V8Belt2008-2010V8ChainMR21990-19954 CylinderBeltMR2 Spyder2000-20054 CylinderChainMatrix2003-20104 CylinderChainPaseo1992-19974 CylinderBeltPrevia1991-19974 CylinderChainPrius2001-20104 CylinderChainRAV41996-20004 CylinderBelt2001-20104 CylinderChain2006-2010V6ChainSequoia2001-2007V8Belt20094.7 V8Belt20104.6 V8Chain20105.7 V8ChainSienna20114 CylinderChain1998-2006V6Belt2007-2011V6ChainSolara1999-20014 CylinderBelt2002-20084 CylinderChain1999-2009V6BeltSupra1990-1998L6BeltT1001993-19984 CylinderChain1993-1998V6BeltTacoma1995-20104 CylinderChain1995-2004V6Belt2005-2010V6ChainTercel1990-19984 CylinderBeltTruck1990-19954 CylinderChain1990-1995V6BeltTundra2000-2004V6Belt2005-2010V6Chain2000-20094.7 V8Belt20104.6 V8Chain2007-20105.7 V8ChainVenza2009-2010AllChainYaris2007-20104 CylinderChainThe 2007 Toyota Sienna V6 has a timing chain. It does not require maintenance.
It has a timing belt. Only 2007 & newer Sienna have a timing chain.
Timing Chain
It has a timing chain.
It uses a timing chain.
The 2.7 liter four cylinder engine in a 2007 Toyota Tacoma has a timing CHAIN
The timing chain on a 2007 Toyota Sienna is designed to last the lifetime of the engine, typically around 100,000 to 150,000 miles. However, it’s important to monitor for signs of wear, such as unusual engine noises, rough idling, or check engine lights related to timing issues. If any of these symptoms occur or you notice a significant decrease in performance, it's advisable to have the timing chain inspected and replaced if necessary. Regular maintenance checks can help ensure the timing chain remains in good condition.
it has a chain.
Chain
Timing CHAIN (s)
The 3.3 liter V6 in a 2007 Toyota Highlander has a timing BELT
does a toyota corolla 07 1.8 has a timing belt or chain