Need ideas, I have a eg hatch with a jdm h22 . The car shows that its over heating , it goes up and down ! I got it from a buddy and before he gave it to me he was having the same problem on two motors. Also the car was ran hot for thirty minutes and then the needle went back to normal. i don't think its the head-gasket. but not sure.

 

are you sure the radiator is not clogged? if he had the same problem on two motors in the same car and the radiator was the same, its probably cloged

 

Your temp gauge is fluctuating? If so you have air bubbles in your coolant system

 

Got to agree with mouab18c1 ^^^ most common cause of "fluctuating" engine temp gauge is air in system, bleed the system and see if there is an improvement.

I also agree that a clogged rad could be the problem, drain system, pull lower rad hose, use garden hose to "fill" rad through rad cap opening, and see how the flow is.

Whar size rad is in the car, full or 1/2 size? 94