What is the thing in the middle of the pic? I seem to have an intermitant leak of coolant from this thing and I don't even know what this thing is or what purpose it serves me.

The help is appreciated.

Robert

 

That's your heater control valve.

 

That sends coolant to your heater core so you can have heat, and that thing you stuck a spark plug in used to be part of your smog equipment

 

i think it's to keep coolant from going through the heater core when you're heat's not on so you don't get excess heat if your AC is on. i would just get rid of it and run straight hose to the firewall, a lot of cars don't have those and they're fine

 

Thanks for the replys. The spark plug is in the smog pipe becuas it was sucking fresh air in and messing up my oxygen sensor readings. This was when my MAF was nackered and I needed a quick fix.