The engine has been rebuilt 5 months ago. The story is as follows.


When the car is idling, after 10 minutes exactly when the cooling fans turn on, the coolant gushes out through the overflow tank.


The same thing happens after an hours of driving. The coolant starts dripping out until no coolant is left and temperature shoots rom the middle position till near redline.


What should be the problem? I have changed the radiator to an aluminum one. I have also burped the system but to no avail!

 

I hate to say it, but you may have roasted the engine if you have allowed the temperature gauge to shoot towards the top multiple times.

It does sound as though combustion gasses are being forced into the coolant.

With the car totally cold, remove the coolant filler cap. Top off the coolant if necessary. Start the car. Do you see a steady stream of bubbles from somewhere in the engine? Rev the engine by grabbing the throttle body. Do the bubbles increase? If you have answered "yes" to these questions, combustion gasses are probably entering the cooling system. Which means the engine must be torn down.

 

i have a question, aaron. when i start my engine cold with the coolant filler cap off, it overflows with occasional bubbles. coolant doesn't shoot out when i start the engine either w/o the cap. you're describing symptoms i have but when i rev the engine, the coolant goes down instead of overflowing...

 

Sounds fairly normal. If you aren't losing coolant, then don't wory.

 

Anybody ever try Evans coolant in their RX7?

 

There are numerous evans threads. Not sure which generation RX-7 you have, but there are multiple threads in the 3rd gen section. Just search them...