I got a 92 civic with some cooling issues. I've replaced the thermostat and radiator and water pump appears to be fine. It still over heats and when going down the interstate at about 70 mph the transmission fluid starts to boil out. What else do I need to check? Could for some reason the coolant lines be clogged somewhere? If so, how do you check or even get it unclogged?

Thanks!

 

Transmission fluid boils out? Doubtful. You sure you aren't talking about the overflow reservoir for the coolant? Because if not you got more serious problems than overheating.

In all reality you might just have air trapped in the loop. Bleed it off. Don't continue to drive in an overheated state. You can/will ruin your engine.

 

^ this

are you sure you mean trans fluid? how would you know its boiling? did you pull off a line going into the radiator and check it? or did a line down there pop? if it did all trans fluid would have poured out.

you probably have air in the system or you need a hg job. hows your oil look?

two ways to kill a honda, one of them is run it hot....fix whatever it is now, or youll be askin about how to change a motor.

 

Probably a bad HEadGasket and possibly fan not turning on.