NTSC screen issues

[Tunerfreak]

Ive got a Carozzeria DVD unit with an 8" or so LCD screen which has an auxillary input. One problem with it is it is Japan NTSC and I am in New Zealand (PAL). I plan on installing it in my car along with a PC as a PC with a graphics card allows the connection to the screen though the S-Video out and the TV output of the PC can be changed to Japan NTSC so as it works properly, so thats that problem out of the way. The screen runs windows fine and is awesome for games etc. Here are some pics of the screen running GTA-SA, NFSU2 and Tokoyo Drift video perfectly and after picture 6 what happens after 10 or 20 minutes:












Ignore the graphics problem with GTA lol thats another story. As you can see after a while the screen starts going green and yellowy and distorted colours, after another 10 or 20 minitues it goes back right again, I do not know whats causing this but I do know when I print screen while the screen is greeny and distorted the image is fine:



So it is assumable the problem is with my Carrozzeria unit, compatibility or overheating or alike? if anyone can help I would appreciate it, I can get more information about the Carrozzeria unit if required. Thanks.