help used jeep today drove around 1 mile major overheat went to just under red pulled into petrol station header tank was empty re filled drove straight back again about a mile have just been out after letting it cool down no water in header or rad when i pulled up checked underneath no visable leak have checked oil dip stick looks ok no white foam but cannot get filler cap off its just turning round in both direction but cant remove it any ideas

 

ur problem sounds very similer to mine when i bought my 88 a couple of yrs ago found out to be blown head gasket on compression side quick way to find out is to take off rad. cap fill completly full, leave cap off, start jeep if water blows out rad. when it starts then u need a new head gasket.

 

Try pulling up and twisting the cap off. When you get the cap off and the motor is cold refill the resivor and give it a few mins it should start taking in the coolent.