How do I tell if my timing belt is broken on a 1992 gs300?

If you can get a valve cover off, spin the harmonic balancer, or the big pulley on the end of the crankshaft, and JUST A LITTLE BIT you do not want to cause more damage, and if the valves do not move the belt is broken and your engine is shot, it's an interference engine. If it broke while running, (well it's not going to just snap when it's not running) the pistons come up and hit valves that are not supposed to be open, so top end at least is shot and possibly a piston. All this is worst case scenario, if the belt is indeed broken

The Lexus GS300 did not start its life until February 2003.So either you typed the Wrong Date or something is WRONG?

GS300 Started Life 1st. Generation in 1991 until 1997,2nd. Gen. 1998 to 2005 and so on,I Don’t know where you Got 2003? Maybe you were talking about a Different Make and Model? But feb. 2003 is Wrong and your user name so close to mine is Making me Look Bad,If your Not Sure Go to Lexus Club or even google it?? herculesx

I'm pretty positive 1993 is the first year for the GS300. I've got a 93 myself and the first gen went from 93-97. So I say 2003 and 1991 are both incorrect. The Toyota Aristo may have started with 1991 model year but I'm not sure if that's correct or not