98 civic lx.. completely stock d16y7..

when i bought it, it didn't have a thermostat so i put one in and bled the system about 7 fan cycles.. the radiator cap was a discount auto parts 16lb cap so i changed it for a 13lb cap. no luck...it will run fine for a while as long as im not going above 3.5 to 4k RPM. also had a misfire code. on cylinder 2 and 4 and a random misfire code... both top and bottom hoses feel hot to the touch. when it starts to overheat it will bubble out of the reservoir.. after it overheats the car wont start i ussually have to jump it... also the hose from the reservoir to the rad was getting kicked of when it would start to overheat so i put a clamp on it... the heat will not work... i did an oil change and the oil seemed fine except it was really thin... no milk on the oil cap but when it overheats the cap seems to get a greyish film on it very thin but a film non the less.... the coolant in the rad doesnt seem to have any oil in it.. but the reservoir seems to have oilresidue on it....fan kicks on fine

so im thinking it most likely will be the headgasket.... but im open to sugestions..... heater core maybe...im really trying to stay away from having to crack the head open....



excuse the long post, just trying to give as much info as i can....