IT IS NOT ABNORMAL FOR THE GUAGE TO GET PAST 3/4 IN HOT WEATHER, ESPECIALLY AT IDLE OR IN TRAFFIC. YOU MAY HAVE AIR IN THE SYSTEM AND IT MAY NEED TO BE BLED OUT PROPERLY. JUST REMEMBER, NO MATTER WHAT DEGREE T-STAT YOU PUT IN, THE ENGINE IS STILL GOING TO GET JUST AS HOT, IT WILL JUST TAKE LONGER, IF THERMOSTAT ID WORKING PROPERLY THE COOLING FAN DETERMINES HOW HOT THE ENGINE RUNS, THE FAN WILL TURN ON AT APPROX. 207 DEG. FOR LOW SPEED AND 216 DEG. FOR HIGH, SO NO MATTER WHAT T-STAT YOU PUT IN, IT WILL STILL GET TO 216 DEG.
WHICH TRANSLATES TO APPROX. 5/8 ON GUAGE AND BEFORE GUAGE STARTS TO DROP IT MAY REACH 3/4.