89 Civic 1.5 runs hot with theromstat runs fine witout thermostat

I assume you mean the bottom radiator hose which means the radiator is doing a good job in cooling the water. Most likely the thermostat is stuck open and the block temeperature is not getting up enought to give you "hot" water through the heater core. Now if you are talking about the heater hoses then there may be only a small flow because the heater water control valve is only partially open or clogged, Maybe the hose collasped or the heater core is clogged. Remove the hoses from the engine and check them and the heater core flow with your garden hose water pressure.

Check that the fan is starting, if the fan motor has gone, that is the cause.

Welcome to Fixya! Ok, You have already Replaced all the Components that would need to be Replaced. You will have to remove the Radiator and take it to an Authorized Radiator Repair Shop and Have it Roded and Dipped. Hot on Top and Cold on Bottom is a Direct sign of a Glogged Radiator and there is only one way to Fix it. Let me Know if you need any more Help! P.S. Been a G.M. Mechanic for 35 Years.

Im Asuming Cooling fan operates Properly @ 200-210 degrees ? if not Temp sensor bad. I would eliminate T-Stat and run it see if gets hot if so and has A/C Make Sure it and Radiator are CLEAN to Pull Air through fast, if so It Has to be INTERNAL I have seen Radiator Additives CLOG UP V8 Engines to total it. Especialy ALUMASEAL the Old Scool WAy was to take off both hoses and T-stat out run Water hose in it Se if it Comes out the Bottom

You should check to make sure you are not getting engine compression into cooling system from leaking head gasket or cracked cyld. head.

You may have not enough coolant or the wrong kind of coolant. You may have used a winter thermostat rather than a summer thermostat. The radiator cap may not be the right one or isn't functioning properly. The pressure escape line off the radiator may be obstructed. Your radiator may have a number of fins clogged, or the coolant pump may not be operating properly. The fan belt powering the pump may be loose or slipping. There are multiple possibilities

Have u checked for bubbles in the radiator while the engine is running, this sure sounds like a leaking headgasket to this technician.

Change your thermostat. If it is easy to get to, remove it, run the engine and see if thise hosees go hot topp & bottom. If they do replace the thermostat.
Even if you already did so, do it again as the one you put in could easily be faulty. Make sure the thermostat is oriented so that the long stem with the spring faces toward the engine block.
If you need a diagram let me know and I'll send you one.
If removing/replaceing it does not solve the problem your radiator is blocked or your water pump faulty.
Blocked radiator is easy to check, remove bottom hose and run a garden hose water thru it and see if it reappears.
Broken water pump if there is cold bottom hose, hot top hose, and no thermostat fitted.
Obstruction in the engine is Very unlikely - but possible.
Hope that does it for u

Your radiator is plugged or the thermostat is upside down

Hot water gets pumped out of engine by water pump, goes to top radiator hose. gets cooled through radiator, leaves bottom radiator hose and goes back into the engine. this means your water is not flowing through the radiator correctly. you may have a thermostat problem. this is very cheap and easy to change.
to replace the thermostat
Follow the top radiator hose to the engine. There is a radiator hose clamp, remove that for easier access to the bolts. There is a removable piece attached to the engine.(2-3 bolts) The thermostat sits in here. Remove the thermostat (piece has a spring) Remember how you took it out and replace the new one in the same way. Put on a new gasket and sealer. Tighten bolts. Replace hose.
Remove the top water line from the radiator to the water pump. The thermostat is found there.
In most cases-- Drain about 1 gallon of coolant from radiator Follow upper radiator hose to engine it should connect to a housing remaovable by 2 bolts Remove housing - note how thermostat is installed and install new in same position Clean both surfaces well Install new gasket Tighten both bolts securely and evenly Fill Radiator Slowly to prevent becoming "airbound" Start car and check for leaks Warm to Normal operating temp and check coolant level

Try this: Use A drill bit aproximately 1/16inch, Drill A hole in the flatest part of the T-stat in the tin part not the expansion valve, Reinstall it and fill with water. This will let all the air out so it does not have to get the engine really hot before the T-stat opens. burp the water line get the air out of the system

What about water pump is it running OK. It could also be the thermostat fuse. Check thermostat fuse. Is the thermostate installed in right way, not upside down. Let me know
Good Luck