superevil

ok here goes. i know that with not enough resistance from a thermostat,your coolant will flow to fast and make your coolant temps lower but your engine temperature higher. i installed an oem thermostat.it made my coolant temps a little higher,but i have way more pressure in all hoses than before(wich was not much before) now when i remove the cap with engine started it releases pressure,before it didnt. it made so much more pressure that my coolant level sensor started leaking(wich i fixed) it doesnt run over half on the temp guage,but my temps are way steadier than before. also,my heater seems to work better with the oem. is this right? or possible or am i doing something wrong? i also have a new factory cap.wich i installed at the same time