okay so i got this 91 integra ls... and it has new headgasket, water pump, thermostat, hoses, and fairly new radiator.... heres the deal sometimes at long lights or when im parking the temp will slowly come up to about 3/4 or so but if i give it some throttle and rev to like 3-4k the temp comes right down to normal.... even on a cold night...and i have been able to do that everytime.... so im confused.... has anybody else had this issue and what was the problem and or fix? i was thinking thermostat? thats actually the second one too.. cuz i put one in and 2 days later the car overheated cuz the thermostat never opened...so i went back and got another one and now once in a while it does this..... or maybe the radiator is plugging?

 

just as a preface, what is the temperature rating of your thermostat, meaning the degree in which it opens?

anyway, i would recommend flushing and filling your cooling system to remove and and all scale build up, then properly "bleed" the system to remove any air bubbles that may be present....half hour job that costs less than 30 bucks

 

Get an OEM thermostat only, yours is not closing this time. Ram air through the radiator when you drive is cooling it down and reving it gets the water pumped throught the radiator quicker and the fan is helping BUT a stuck open tstat will run away at idle and overheat. See if both of your hoses get warm together when a cold engine is warming up.

Go look at some of my recently viewed threads, there have been several overheats this month alone, OEM all the way here bro.

 

Duane is certainly right, stick with an OEM thermo. That is most assuredly the culprit.