I am in the process of ordering a timing belt kit for 2006 Volvo XC90 2.5T, where can I fing the engine number they are requesting, for example!
GATES Part # TCK331 {#2523310} PowerGrip Premium OE Timing Belt Component Kit; 3 Components (1 Belt, 1 Tensioner, 1 Idler)
Engine. No. 3188688 & Before


Thanks

 

Search the web and you will see where you can find the Engine Number printed, usually on the timing cover area.
Xc90 2.5t Timing Belt Change - Volvo Forum : Volvo Forums

Do NOT use Gates, it is hit or miss.
Volvo sells the kit (TB, mechanical tensioner and idler pulley) for $120. The price is very good, so don't use anything else. Stick to Volvo brand for this job!