Thermostat housing

I broke corner off thermostat housing today, changing thermostat, and ordered new one. The new one comes with gasket, but no gasket on old one, just rubber seal that encircles thermostat. Are they supposed to use a gasket when replacing? Just curious. Thanks to all

this was on 2000 prerunner, not 2004. Should be the same though.

 

I just rebuilt my motor and it used a gasket, I also used thermostat and waterpump rtv lightly around the block to hold it in place and a few dots on the yoke. I haven't had any issues.

 

I use Toyota thermostats on my truck and IIRC they all had the rubber O-ring and no paper gasket. I don't think that the thermostat housing requires a gasket. The O-ring on the thermostat should be enough.