@Oasisplayer311 do temps come back down when you rev the motor? If so, that is a good indication that something is restricting the coolant flow. Thermostat seems likely.

My temps are identical to @Richard Gallant with the same grey 180 thermostat. My idle temp is 190-197 no matter the outside air temp, regardless of A/C on or off. I idled today for 20 minutes with max A/C in 90+ degree humid temps and the idle sat at 190-197 the whole time.

 

Sounds like I have a coolant blockage then. Cause they do drop down when reved. I ordered everything for the inline thermostat mod. So when I go to take everything apart I will hopefully catch the problem. I believe there could be pieces of old plastic from the "T" pipe above the radiator getting caught in the Thermostat.

 

everything will be fine when you get that inline thermostat mod kit
you will never have to worry about bad thermostats grey black where from etc
best thing I did

 

Got everything installed and I'm getting extremely mixed info on the direction of the thermostat. Plus my car keeps getting wayyyyy hotter at idle than should (215f with a 170f thermostat) this is the setup I'm going for

This is the side going towards the engine

This is how I have the pipe going from the (water pump to 3 way).

Everytime it keeps getting too hot and I'm not sure why. I'm getting mixed info everywhere so any help is appreciated

 

@Oasisplayer311 Try with no thermostat you do not hurt anything, might take a bit longer to heat up. See if there is any change. The idea to to eliminate the simple issue. Also any coolant loss and how is your oil level ?

 

No coolant loss and oil level is on the lower side of good (the lower of the two indents)

Also some history. The engine is a 4.6 with 90k miles from a RUNNING P38. I broke the engine down to the rotating mass and rebuilt from there (new front cover with oil pump, new lifters, push rods, rockers, ect) so with that is a new Water pump, fan clutch, radiator, AC Fan, and thermostat. I'm probably forgetting other things, but it's all NEW. Even tested the new fan clutch the other day when hot to make sure it wasn't bad because I can rev the engine and it cools down.

Everything has been running good until I use the AC in 95+ degree weather. The car will run at 194f all day. Once I park it, it will slowly crawl up in temp with the AC on, I turned the car off once it reached 221f at idle.

This is why I'm going with the Inline mod. But it's giving me a thousand headaches more. Almost want to just delete the AC and deal with the humid hot southern weather

 

Forgot one thing AC compressor,if the bearing is going it can cause a overheat. Basically it creates drag on the the belt, upping the RPM will overcome that. Easiest way to test is with an non AC serpentine belt, so you take the compressor out of the equation a good A/C shop might be able to check it

 

Alright guys. So got the inline thermostat installed, but trying to figure out the direction of the thermostat at the top of the Radiator. So which way will this face? Towards the engine? Or towards the top of the radiator?

 

I believe that faces the rad

ask who sold you the kit just to be sure

 

I can confirm that side goes toward the radiator.