Sup guys. I have a 91 Civic hatch with a y7/z6 swap and recently it's been overheating here and there within the last 3 months. Driving the car within 30 minutes, between 30-50 mph the temp climbs up slowly. Anything under or over the temp drops back to normal. I've replaced the head gasket twice, new thermostat ( but now it's running without it). and new water pump. All autozone parts only. When I was doing my first head gasket change, I forgot the remove the hose connected to the heater core and accidentally yanked on it and now my heater core is broken. I have it bypassed for now till I can get my overheating issue solved. Somedays, I can also smell coolant through my driver side while driving on the highway. My driver floor is kinda damp, maybe radius of 3" but also not soaking. But it's not leaking through from the heater core at all from the inside of the car. Passenger floor is completely dry I can't figure it out. Radiator is loosing coolant probably like 2oz a week, not sure if that's normal. I check my car every Sunday. Anything will help. Thanks in advance!

 

did u take the head to a machine shop... it could be warped from the overheating. Make sure that all the hoses are going to the right places. and that hose to the heater core is very important need to take care of that asap

 

I wouldn't imagine driver's side floor being wet to be coolant related. Seems more likely that would be water leaking in from outside. Why have you removed your thermostat? The system is designed to operate with it in place and removing that restriction can cause you trouble just the same as a malfunctioning thermostat. You can easily test a thermostat with a pot of boiling water. I tend to avoid aftermarkets as I have seen new ones malfunction or not work at all. Also, why have you done your head gasket more than once? Did you do it the second time as a precaution or did you see symptoms of a leak. If it has been a while since the most recent replacement, I would check again for symptoms that it has leaked again. As sasinorm01 suggests, you could be dealing with a warped head or other problem that will not be possible to fix simply by replacing a head gasket.

 

You sure you have bypassed both ends of the heater core?
Sounds like it possibly is leaking.

And +1 for upnsmoke suggestion to put the thermostat back in.
In some circumstances the water will overcool the engine which your computer will not like.
Other times the water may flow too quickly through the system and not transfer heat properly causing overheating.

 

Ditto the above^^^ running without thermostat is never a good idea, [emergency only], first thing that needs to be done is to replace it, OEM or good quality OEM replacement, you can not do proper diagnoses of the cooling problem without it.

Because of the symptoms I suspect an airflow problem.
Is rad fan working properly?
Is it a 1/2 rad or a full size, [stock is full size]? 94

 

If you remove the thermostat, the coolant circulates too quickly and doesn't spend enough time cooling in the radiator.

Put a thermostat back in.

 

I really hope it's not warped. This is the last thing I want to think of since this is my only car and my daily. Which makes it difficult to do anything.

It hasn't rain or I haven't wash my car for a couple months. So I really don't know how the water is getting in there. It's just moist. I do smell coolant here and there when I'm driving so that was the first possibility to think of. I did my head gasket more than once thinking I had it on wrong. Since the head was off, I just got a warranty exchange. I don't have anything leaking from my car. It's super dry after letting my car sit outside for a day or so.

Yeah, both ends of the hose connected to the heater valve adjuster. Unless those hose go somewhere else? Thing is I can't find any leaks and my coolant hasn't dropped since I created this post. Weird.

I took the thermostat off thinking it was blocking the coolant.
Fan is on a switch manually. Stopped working ever since I swapped the mini me in even though I have the wires connected correctly. I think relay is just dead.
Rad is stock and full size using stock fan

Thermostat is back in./

Lately it hasn't been overheating since the weather temp dropped from mid 90s to 70s. Whenever it's hot out, it climbs up past half a little bit but not quiet as fast anymore