okay so the car is a 1995 civic coupe dx. Bone Stock. When I start it it runs fine. Then after driving for about 10 minutes the temperature gauge just shoots up to the H. I turn the heat on and it goes down a little but just goes back up. Also it takes a long time for the heat to actually become warm, and then even when it's warmed up fully it isnt even that hot. Also now its starting to idle weirdly in park, and while stopped at a light. It has a low intermittent idle that goes up and down in the rpms. I replaced the thermostat, and it didn't make a difference. I need some help on this one so im coming to you guys, any help would be greatly appreciated. Thanks!

 

sounds like you need a new water pump. but before you do make sure that you bleed all the air out of the system. your symptoms are also consistent with air in the system.

 

get thermo first water pump would make it get hotter way faster

 

X2