I searched the old posts to see if I could find an answer, and I couldn't, so here we go.
I have a 94 civic d15b7, completely stock besides suspension and wheels. I bought the car last year, and it had amazing heat. During the sping/summer I had to hardwire the fan to the fuse box because the guy that had it before me cut the plug off the harness, so I got the fan working again, but it turns on with the key and stays on all the time and it was still overheating, so I replaced the thermostat, and it stopped over heating for a few months ago until recently. And now I have very minimal /almost no heat, and it still over heats sitting in traffic, and the air doesn't get any warmer, but once I get moving again, the temp guage goes down to normal.
I'm thinking that the heater core is clogged, or the thermostat went out again. But at the same time, with the fan running constantly, (in my way of thinking) it still shouldn't overheat, even if the thermostat is bad.
It's starting to get really cold where I'm at, and I need my heat asap, and to figure out the overheating issue.
​​​​​​Any help is greatly appreciated.

 

Oem t-stat or aftermarket?
Go to the junk yard and get yourself the correct fan plug. Fix it so it will function like it supposed to instead of running all the time.

Change out the t-stat with an oem one, bleed it per fsm. See if that will fix it.

 

It's just an oe thermostat from orielly. But that's what I was thinking. Just replace the thermostat, and bleed the system. I'm about to swap a b18 in it here soon, so I may or may not try to find the stock plug.

 

Is the rad fan running in the correct direction?94

 

First off, is the cooling system full? Check in the radiator when the engine is cold. Do not just check in the white plastic tank.

 

Yes, the cooling system is full. And I'm pretty sure the fan is spinning the right way, but I'll double check when I get a spare minute. At work right now.

 

Just checked the fan, and it actually was spinning backwards. So it's spinning the right way now. So that should help with overheating. But what about heat? I'm thinking either the system needs bled, or the heater core is stopped up.

 

Make sure that when you push the lever on the dash to hot, the valve on the firewall opens all the way. The cable on the valve should pull all the way back.

To check the core drain the system, disconnect both heater hoses from the engine, put dash lever on hot, and flush water through the core both ways with a garden hose. It should flow freely.

 

The heater adjustment in the dash actually doesn't work. I had to move the lever by hand behind the console, or the lever on the hose at the firewall. I have a little bit of heat, but it's really not enough to even call it heat. Lol.

 

It's likely you don't have the air door or the water valve all the way in the "hot" position. Moving the lever pulls a cable which connects to a mechanism on the bottom of the heater box that does those two things.

If you have the water valve open and the core is unobstructed, both heater hoses should be very hot to the touch. But you will not get hot air if the air door (which is toward the right side of the car, pushed by a rod from the mechanism on the bottom of the box) is not in the hot position.

 

The cable running from the control to the lever behind the console is broken, but I moved the lever to the hot position, and it also moved the valve on the one in the engine bay with it. Is there another lever to check?

 

Switched the lever on the bottom of the heater core housing, heat is ******* amazing. Lol. Thanks man, I really appreciate the help.

 

Now get over to the:

Pull-A-Part
Cash for Junk Cars & Used Parts: Pull-A-Part Auto Salvage
7114 Centennial Blvd, Nashville, TN 37209

And get you a new set of climate controls, and or the parts needed to fix yours and make this alot more convenient to adjust, and learn a little more about your car.

 

I already have the whole climate control assembly. Pulled it out of my girls wrecked hatch when we pulled the swap out. Was waiting until I did the swap to this coupe to switch them out. Just wanted to get some heat for in the mean time lol. And I've already been to pull a part, and all the other junk yards around here, and found only a handful of eg's.

 

Well it's unlikely that you'll want to run the AC any time soon so you've got time. Just keep the valve switched to hot for now.

 

ok so the heater is working, what about the overheating?
Plenty of coolant?
Thermostat working (pot of boiling water will tell ya)
Coolant moving?
Air moving through the radiator?
Ignition timing correct?

 

Everything works as it should now. Haven't noticed any over heating since I switched the fan wires around, and the heat kicks *** now that the door is open.

 

And the owner before me removed the ac and ps like every other Honda kid does. Lol.

 

yeah, because that wastes so much horsepower. When I was a kid, the first thing we did was cut the belt to the a/c because that burned a whole 7hp to turn the pulley,. Now I dont even look at a car that the a/c doesnt work. Now if Im buying a car it has to have two things
Great heat
good a/c