I bought a 1985 RX-7 GS last week, and while driving normally, in stop and go traffic, i noticed the temp gauge was completely maxxed out, oil pressure was very low (20lbs) and it was idling around 150 RPM (it normally idles around 750-1000). This was about 4:00 in the afternoon. I pulled over as soon as I could, and heard a boiling sound.
I allowed the vehicle to cool, (5 hours, in the shade) and checked the radiator and overflow reservoir, and they were empty.

I filled it with water, and it maintained normal temperatures on the drive home. I flushed the radiator and replaced the upper and lower rad hoses. I also changed the spark plugs, and air filter. I added carb cleaner at the same time. When I went to run the radiator flush through, the tempature rose to boiling, while idling in the garage. I shut the engine off when I heard it start to boil.

Does anybody have any ideas?

Thanks!

 

thermostat?

 

I forgot, I replaced it with the hoses.

 

Cold start, then immediately boiling? Yeah, that's not boiling, that's compression gases making their way past your housing seals into the coolant system. I'll bet the water's not even warm to the touch.

My guess is, the first time it overheated (low/no coolant), it fried the water seal O-rings and the engine is now toast. Do you smell a faint 'burned' smell from either the carb or the radiator? If so, that's a telltale sign.

I hope it's something easier, but rotary engines don't tolerate overheating even once to 'Max Temp'. HTH,

 

It started boiling after about 20-25 minutes of idling. I was working the radiator flush through the system.

The smoke the first time did have a slight sweet/antifreeze smell, though.

Thanks

 

That does sound like a water seal leaking compression in to water system

 

With a broke water seal, is there anything other than a rebuild to fix it?

 

No has to be rebuilt to fix problem

 

Is the fan clutch a possibility? The car maintained normal tempatures while driving on the freeway, but has trouble when idling or in stop and go traffic.

 

I had a clutch fan problem. was fine when driving in town or a highway speeds. Temp when up when standing still or real slow stop and go traffic. Get back at highway speeds and temp would go down. Temp wasn't pegged but I'm sure would have if it was left just standing still at idle.

 

I had the same problem. if you got the sweet smell coming from the exhaust its a bad coolant seal.time for a rebuild