thermostat housing bolts on to?

[1991toyrolla]

Hello Folks,

I want to do a coolant flush on my 91 corolla dx with 39,000 miles on it. I did it at 20,000 miles 10 years ago. I need to know the name of the part that the thermostat housing bolts on to. This part also has a heater hose, one more smaller hose, a bypass hose possibly?), & (I believe) the coolant temp sensor. I noticed some type of build up where the hoses clamp to this part which basically is located between the thermostat housing & the engine head. I would like to remove it & clean it or replace it if necessary. I assume it will be a dealer item so I need to know what to ask for if I have to buy one. Anyone ever buy this?

I am currently driving this car approxamitely 150 miles per week plus a 700 mile trip every 4 months on average. I want to replace ALL the hoses. I don't want any surprises so I'd rather be pro-active. Also, any coolant recommendations? The owners manual says to use ethylene-glycol coolant with no alcohol.

Thanks.

[Flashmn]

Well wouldnt that be the actual thermostat housing?

As for coolant, green stuff will do.