recently did a rebuild on head and bottom end.
car has been driving great up until today

when car is idle, the temp of the car slowly increases, but when i step on and hold the gas at 1500-2000 rpm, the temp goes back down to normal.

thermostat is new (duralast, autozone brand)

i dont think i hear/feel the fan kicck on either.

i am only running water in the cooling system at the moment.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TrueUntilDeath.com &raquo;</TD></TR><TR><TD CLASS="quote">recently did a rebuild on head and bottom end.
car has been driving great up until today

when car is idle, the temp of the car slowly increases, but when i step on and hold the gas at 1500-2000 rpm, the temp goes back down to normal.

thermostat is new (duralast, autozone brand)

i dont think i hear/feel the fan kicck on either.

i am only running water in the cooling system at the moment.</TD></TR></TABLE>

Umm, well water is one reason it boils when hot so it'll evaborate and once you open the plug itll spray some steam at yo face if its hot. Other than that try the FAN switch, i know that cuz i had a similar problem. The Fan switch could be expletiveed up see if your fan even turns on or not thatll cause it to overhead on idle but unce you get going the cold air hits the radiator and cools it. So rewire your fan switch its simple.

 

i had the same problem but it ends up i just forgot to plug the fan in when i put the motor in. when you give it gas it circulates the water...thats why it cools down.

 

thermostat if i spelt it right change it that was my prob!!! i had the small thing going on before i changed it

 

not the thermostat

i changed it, i still have the same problem

 

i put in a 170 degree thermostat which is the stock temp for it to open up.

 

found my prob. radiator cracked a little and was letting out the pressure / vapors