I have a 2.4 out of an 08 HHR and am installing it into another car. I am wondering if someone could tell me where the third small hose right off the thermostat housing goes? To clarify, there are two hoses going to the cabin heater core, the big one to the radiator, and then there is the third next to the radiator one. Clearly seen in the pic here: https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/

 

Welcome to the site are talking about the small hose connection on the thermostat cover? On my 08 it is pugged off with a rubber plug. Think that port was used on hhr's with a oil cooler. The hoses came off the thermostat housing to the cooler the to the lower rad hose.

 

Here is a diagram of one with a cooler. My 08 does not have a cooler so it is blocked off.

 

I saw else where on the site '06's had the oil cooler as Lucky shows, my '07 does not have the extra nipple on the T-Stat housing.

 

Thanks, the pic perfectly explains.