So ive had this civic for a little over a year now. It has the d16z6. This issue has recently started. I have plenty of coolant in reservoir and radiator. Drive for a while and all of a sudden I notice my temp gauge is at red.. keep filling it with radiator cap off and that side of engine elevated. Keeps happening. I replaced the thermostat and the radiator cap was shot. Did a leak test for gasses and its fine.. tonight it did it again and I just filled it up the other day. Popped the hood quick and heard a maybe hissing/bubbling noise somewhere around the block. (It was dark) also I havent noticed my fan ever go on. It does work though. Wtf you guys think it could be?? I need 1 more year atleast outta this thing.

 

If you let it go to the red (especially more than once), there's a good chance your motor is already fucked up.

Start off by parking your car on a piece of cardboard or throwaway wood. Pop the hood, start the car, and let it sit there running. When it starts overheating, turn it off, and look for drips, leaks, or steam. There shouldn't be any. If there is, pinpoint where it's coming from. This should go without saying, but BE CAREFUL. COOLANT IS HOT!

After you're done with that, do a compression test and post the results.

 

Mine had an issue with raditator cap where it would seat on the fill neck, had a chip out of that lip, so new radiator/cap went in, then the hose burst right under the distributor under the block. look for bulging hoses.

 

go to a radiator shop and let they do a dye test.....they add a colorant and if there is a leak the dye color will be visible....

 

Pressure test the cooling system and look for leaks

 

Alright I filled it up this morning and noticed there's a minor leak for the gasket attaching to the head. would that cause so much coolant loss?

 

That should be obvious at this point - a broken gasket. are you talking about the head gasket, or the intake manifold gasket? An IM gasket is stupidly easy. A head gasket is still relatively easy, but not "stupidly" easy...just "kind of" easy if you're comfortable around wrenches and ratchets.

 

When the engine is idling if the upper radiator hose is rock hard from compression gases you probably have a blown head gasket or a crack in the block or head. The dye test will help locate a crack.

Squeeze the upper radiator hose with your hand to see if it's hard.

Also if you see bubbles in the coolant overflow reservoir when idling that's another sign of the above problem.