ok i have a 99 civic b16 with arp head studs and i can drive the car around for about and hour and it starts overheadting i let it cool down and check the coolant and some of my coolant is gone i have change the t-stat, radiator,check'd compression and it was 150,150,136,135.there r no leaks ne were no water in my oil from what i can tell and no oil in my water and i have just changed the headgasket about 2 months ago..oo yea and when it start get hot it idles up and down,and its also a new radiator cap.i am stump and in need of help bad lol

 

the coolants going some were if you say it losing some. my guess is its burning it. there is a test u can do to check for hydrocarbon's in your coolant.

 

how can i run this test

 

You had two cylinders side by side that were low and about the same compression... Thats almost always the head gasket :/

 

this might help you distinguish the cause of the overheating.

the temperature gauge will swing back and forth until the entire system is warmed fully. This is because you keep introducing "cold" coolant from the radiator into the engine, rapidly cooling it. When the temp falls enough, the thermostat closes, and the temp goes back up, repeating the cycle. This is due to a valve which lets you get heat before the thermostat opens up. It keeps the warm coolant in the engine *and heater* when the thermostat was closed.
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well i changed my head gasket and it still runs hot

 

is the ecu throwing any cells?

 

If the engine overheated there's the possibility that the head has warped. Therefore your new head gasket won't seal properly and you'll burn coolant and continue to overheat. Your compression test numbers lead me to believe that's the case.

Just something to keep in mind.