2.3 DOHC motor - correct operating temp

[fixkick]

now lets look at heat.  (engine to coolant)
see this great drawing graph...
in closed loop , the black vertical line is at stoich,
then if fuel goes lean to the right a bit, efficiency  rises , heat the the water jackets goes DOWN as the red line peaks,.
The reason we use Stoich is for low smog, not max HP see on gray cloud point.
Unless you go super lean (and felt in the seat of the pants) it will not run hotter coolant.
yes lean can burn exhaust valves tips. as the do get hotter, but not the water jackets. (this lean hot combustion lasts for shorter time, and does not expose the cylinder walls with more heat but less (yes complex that) that is why late timing puts  too much flame front on the walls, of the cylinder. bad for the cooling system that.

The leaning out, same fuel used (volume) makes more HP, and wastes less heat, until the cold air (oxygen) is so great the fuel is heating mostly air, and efficiency drops.
so lean only wastes heat if way too lean. waste heat is the inverse of the red line here.
not to mention once too lean the spark can not fire off the lean mix and it misfires.




I bet you , your engine is not overheating the coolant.  in fact a tad lean is less heat to the coolant.
misfire can be a cold slug of air.
or way too late to spark fire and then dumps lots of heat the the cylinder walls. just like late timing does. (and HP FALLS off FAST) felt..

I so appreciate you working with me on this,  so if you're correct and the engine is not overheating the coolant, and we are sure the ECT temps are correct (We are from the tests performed) 

What's next ??

  This weekend I am going to put in the new thermostat,   While I am at it since the coolant will be out I will take apart at the heater core hose connections and make 100% sure there is no obstruction or low flow of pipe 22 and the heater core itself (using your pic) since coolant comes from the back of the engine, through the heater core to the thermostat housing.  

I know we discussed that if there was obstruction the thermostat would surge but I am not experiencing this.

While I have the thermostat out I will take off the serpentine belt and see if I feel any play i the waterpump and put my fingers in and check all the impeller
blades.  

What I am doing is probably 'make work' but it will be piece of mind to me knowing that there isn't any obstruction.
  

 I spent some time today just looking over the system as a whole,    It was too hot in the shop today for me to want to pull apart the cooling system.

 Still same temps at idle. close to 240 .   Looking at the above diagram Coolant leaves the engine across the ECT and into the heater core, leaves the heater core into Pipe 22 and then onto the thermostat housing.

 I turned on the heat cabin heat with the thermometer with heat on low and the temp at the vent only got to 120.     

 If the heater core was operating properly, wouldn't we expect to see the temps out of the vent higher?   

 Could part of this temp management be because the heater core is blocked?      

 I am getting coolant to the wax pellet leaving pipe 22.

 Even though I used an air lift system to put coolant in I thought I heard a gurgling sound in the cab so there still might be air in the system.

 I forgot to also tell you that this Sport has a 2" body lift so the heater core is higher than what it is stock.  Could there still be air in it?

  I could also be totally full of SHI* at this point to, not knowing what I am doing.

  Back flushing the heater core was a big bust..  It was in very good condition I got very little rust out of it.

  At least I know that it's not plugged..  I didn't get a chance to change the thermostat yet.   That will probably be next weekend.

hello and good morning to you:'
the tube 22 flows all the time if the heater core clogs or owner loop (bypasses a core) the other hose 19 sneak that hot water back to pipe 22. and thermostat will stop hunting.

all we know now is:
themostat is out off control, it is my guess fully open (240f sure would be) , and can never regulate as it must, so sticks open from very hot water hitting it from 22 pipe feed.

1. assuming the thermostat is ok.  that leaves,  
   
2. weak coolant flows,
   
3. rad tubes blocked. Iniside
   
4. pump issues, impeller blade damage of some kind , or belt drive slippage (im sure not you allowing that slip)
   
5. massive air in system
   
6. RAD too small.
   
7. air flowing through the RAD , insufficient.
   
8. or J18 oddness.  (the hose 19 failures,? missing or blocked, 19 must be there, and most flow water all the time. even TB can block it.
   

or we are chasing phantoms. 
The normal car has  ECT below thermostat and flows from very hot top of heat coolant past the stat , and to the top of RAD to be cooled down soon.
so on a G16 car,  the 180F coolant is exit temperatures.
The j18 , sucks in cold water (coolant)  at the thermostat and would cause the thermostat go nuts , if not for the pipe22 actions.

The J18  pump then flows water into the head'/block jackets, and gets hotter, more than180F (as it started at 180f) and then exit the top rear of the head and will be hotter
and the ECT will read wrong or reads exit temps not thermostat temps. . The ECT is  not in the normal place.
the thermostat on this car controls cold water input to the engine, not output like normal cars.
ahh but that is what I see at first blush but am wrong, above (1/2 wrong)
It  thermostat in this car does run off the hot side,  this is the tricky part,

lets call hose 19 the red hot hose, this hose runs coolant at full engine exit hot temps.
that means that very hot temp, sneaks that very hot water back to pipe 22.
pipe 22 then puts this very hot engine exit hot water to the base wax pellet of the thermostat and only this sneaky hot water makes the thermostat, act just like G16 does.
very tricky this. no?

that means the the heater core can cause and illegal water temp drop, with cab blower fully max on.
that hose 19 bypass sneaks hot water back to the thermostat and prevents the cab heater core for dropping said temperatures,  and causing thermostat errors.
make sure all your hose 19 path are good.
or as a test ,one could  loop the heater core hose set,  jump 25 to 26,  this will slam very hot water to the thermostat. (as would be normal)

the sad part is we do not have sensors on the back side of the thermostat to know what is really happening. (180f regulating is correct, nothing else)

if the thermostat is out of control , the Rad is not working.  

the key fact is , that the thermostat does regulate , based on hose 1 heat.
what happens is on say driving fast up a hill the engine makes more heat and dumps this to the water jackets and the thermostat opens more sucking in colder water and preventing  the water temps from rising. (regulation)
if the ECT shows 250f, (saw it) then means , 250f must hit the thermostat WAX , the wax expands and slams open the thermostat poppet, and if the temps dont drop , flow is not good or the RAD is not working.

this is why I wish you can measure all temps on the pump casing,  even try 2 IR GUN some lie.  only point to metal, when too hot engine.
pipe 22 is metal and best place to measure  too is at its end just as it enters pump casing.
cheers ! those are my thoughts , the AM