I have been battling this problem and now need some answers, I have a 90 gtu, I dont have an radiator fan shroud, no thermostat, I start my car up and let it idle for a pretty good amount of time, it gets up to running temp and idles fine then I let it sit a few more minuttes past it heating up to running temp then it just starts spewing water out of the overflow tank untile it eventually runs it low on water and it starts to heat up past normal, I need an eduacated answer.

 

How have you been "battling" this problem if you don't have a shroud or thermostat?
What other steps have you taken to fix this issue?

Obviously, none.

This "useless forum" has actually been remarkably generous since your first sentence not only describes the problem but also contains the cure...go get a shroud and install the proper thermostat, dummy.

 

lol
if u removed the thermostate and rad shroud why dont u just try draining all the coolant out and replacing it with sand.

put ur shroud and thermostat in moron

 

Put the shroud back on and install a thermostat.

 

And you wonder why the car is overheating?

1. The shroud is there to direct air through the radiator and into the fan. What do you think happens if it's not there? The fan just churns air in the engine bay and very little of it is drawn through the radiator and oil cooler. In fact I bet that your oil temps skyrocket even though coolant temps still show normal on the gauge. You would have found this with a search for "no fan shroud" or similar.

2. If you had looked at the Factory Service Manual or Haynes manual, you would have found that the thermostat in the RX-7 is a bypass thermostat. This means that if you remove it, a bypass hole in the water pump housing is never closed, and about 40% of coolant flowing bypasses the radiator and recirculates. You would have found this using a search for "no thermostat", "thermostat removal", etc.

3. If I'm not mistaken, there is a link to my cooling system troubleshooting article in the FAQ. If you can't find it, here's the direct link: http://www.aaroncake.net/rx-7/cooling.htm