1996 16v 1.6L therm-o-gram of cooling  , low milage top condition subject vehicle. 100%
a brand new "STANT"  192F Thermostat , with new "correct" rubber surround  o-ring gasket, not upside down , wax down, bleed jiggle pin to front of engine.
1992 and newer cars with 4mm thermostat rim must have the rubber gasket. or all cooling WILL GO FRIGID.

The tests conditons ,the "Givens":
Control test, is tool working?
ambient  out door temperature 60F  (50% humid)
Side walk temp, 61f (control 1) ( I shine the IRgun down and ...)
Body of car 65f (control 2) IR Gun works. (Pyro gun)
time :10am
I drove  5 miles (TEST 1)
idled for 15min.
The dash gauge  temp shows  3/8" of and inch ,up from the letter "C" (the guage is a toy but this is a fact, as is the sender is new)

My OBD2 Scan tool shows  shows ECT sensor at 190-200F and is in  close loop!

Test 1: (5 miles, too short a run)
These first readings are useless, I did not get the engine up to full operating temperature,  this is just to show how easy it is to fail...In colder climates,  even easier to fail.
All reading in F degrees.
STAT top housing,  150F
RAD top tank right , 150
RAD top Left, 140
RAD bottom tank,right, 88F  (note huge drop in rad temp. doing it's job ,)
RAD bottom, Left, 111
ISC front edge, 140
IAC front 135
IAC rear  143
Induction main pipe (top of engine huge pipe to MAF,  induction heater coils 16v (92-96 in 97 it's removed and bypassed by SUZ),  right pipe, 161F
Induction. main pipe , Left pipe 136  (drop) (this device has 2 nipples, IN and OUT, the Input is hotter. this one is OUTPUT.
Heater core hose top 156
Heater core hose bottom, 147  (about 10 degr drop)
Rear of head main cooling  fitting, 123F ( head is now where near fully hot yet)
Rad output bottom metal tube, #8 = 90F

Part 5 , suction manifold,  156F. ( this is the manifold section behind the water pump, suck port)

Test 2: Done correctly this time, (50 miles , 25 round trip) A truely hot engine. On a cool day.

Long trip data:  50 miles. I parked and take fast readings.
Ambient 70F, sidewalk is 64F (control)  all below is idling.
STAT housing,  160F  ( if I idle car for  10 more minutes I get t this 170 reading)
RAD top tank right , 156F
RAD top Left, 159F
RAD botton tank,right, 125F  ( the rad has a total drop of  about  34 degree's) Its working. 
RAD bott,  tank Left, 138F
If you check each rad tube in the core,  at top "1 inch below tank" and bottom , 1 inch above tank, you will see this same huge coolant temp. drop if not , that tube is cogged.!
check each rad tube for a drop...
ISC (electric idle control and TB heater) front edge, 148F (never lower)  (I  guess at 180F+ inside the temp. must exceed 158F or the IAC will malfunction,.
IAC front hose 138F (100% thermal) (rubber hose reads low)

Induction main pipe (top of engine huge pipe to MAF,  induction heater coils , 162F
Induction. main pipe , Left pipe  146F  (see drop from above?)
Heater core hose top 106F (keep in mind  the rubber is way cooler on the outside than inside. and that the core has no On or off valve, in line)
Heater core hose bottom, 117F (fan on full speed)

Rear of head main fitting, 123F  (the pump feed cold coolant to the block at front of block and up to head and out this fitting, then feeds the heater coil.
This fitting is a heavy heat sink to the head so reads closer to head temp. and not like 

Rad output bottom metal tube, #8 =  oop's i missed this. my guess is 95F .

Part 5 , suction manifold,  164F  ( this is the manifold section, behind the water pump, suck/mix port) 

Keep in mind that the inside temperatures are the most important:
Note, that measuring rubber hoses is going to be way lower readings, as it is an insulator of heat rubber. ( about 75deg F lower)
Aluminum fittings thick and act as a heat sink to the coolant, In fact the ISC {electric only} is exactly that, it heats the Throttle body. These parts read about 40f less that real.
For sure the best readings are metal.
and steel is better than alumnum , see part 5  , the pumps suction manifold is steel and
reads 164F,  this is the cold water coming back from RAD and is a mixing chamber of cold RAD water and all engine hot water. (+bypass, heater , and IAC chain)

I hope my thermal gram helps someone...

soon' my 2.5L v6 data:

8-14.2009  kick-fix.com
V2 , html , 2-1-2013