Ok I am working on my 88 FC. I let a freind drive it and he threw the altenator belt off and kept driving it well the blew the plastic thermostat housing off so I replaced it and the car ran great but it started to get hot and then the lower radiator hose blew apart I shut the engine off before it got to hot and replaced the hose. Well now the car runs fine at idle but as soon as I start driving it, it will start to run hot and overheat. It blows out a little white smoke when you first start it so I don't know weather it blew the o-rings or what. Oh the hotter it gets the more pressure builds up in the system the hoses will get really effing hard. Oh the car is an 88 FC I put a 91 motor in it and it had no cooling system troubles before. PLEASE HELP ME

 

Start here:

http://www.aaroncake.net/rx-7/cooling.htm

But it does sound like the engine is damaged based on your description.

 

Thanks for the link I think my engine is damaged maybe I will try the water seal treatment as I think it will help and it won't make it any worse. Oh the engine will idle all day long with no problems it is only when I drive it. I also tried taking out the thermostat which did not help any. I and the water pump will get a nice flow of water threw the radiator so I know it is not the water pump anything else it could be.

 

I'd start with a new thermostat.

If a coolant seal O-ring is just starting to go, the "block weld" leak stop stuff has a good chance of working.

 

Well I just got done testing the thermostat it is good I put it in a pot of boiling water and it popped open when the water started to boil. I think the o-rings are just barely starting to go so I will try the block weld stuff as soon as I can get a ride to the parts store lol. I will give you guys an update as soon as it is fixed. Oh and thanks for your quick replys.

 

Remember, the "block weld" trick is only an option of LAST RESORT. Yes, it will likely work. But it will also coat the entire cooling system (rad, heater core, etc.) in the gunk, which requires a huge cleanup effort. Also, if you intend to rebuild the engine, that gunk is hell to clean out of the cooling passages.

 

My old NA had Barrs Leak in it for over a year, and was still holding when I sold it.
(Sometimes you get lucky.)