everytime after driving in high traffic .. i turn off the car .. but leave the power running so the fans kick in .. i get the coolant buzz .. where is my coolant going? whenever i open the tstat to pour in coolant .. the car drinks about a 12 oz before its full again .. i dont see any areas where its leaking .. any ideas where im losing about 12 oz of coolant each time? im pretty sure i burped the system too .. so i dont think thats a possibility

 

Any white smoke or steam out your exhaust ?
Could be a small pinhole leak somewhere too.

 

get it pressure tested. then test the ast cap. also look into the lines that go to the overflow tank they may be getting thin and collapsing under vac or even leaking. the anwser to every where is my coolant going question is to get it pressure tested to find out.

 

nope no white smoke coming out of exhaust while driving .. only white smoke during start up

yeah im about to just replace the ast unit .. preferrably pettit ast .. anyone know a good place where i can get it for a good price? i know rx7store has it for 150 but i think i heard you can find one for about 100 bucks

 

Rather than just checking to see if its white, I'd go to the back of the car and see if it smells like burning coolant out of your exhaust.

Rotary engine coolant seals can fail in time, another way an engine can go .

How many miles are on the engine?

 

You're "pretty sure" you burped it? How? If you didn't use the throttle body coolant line bleed method, you probably still have some air in the system.

Also, you mention that you turn the car off but leave the ignition on "so that the fans turn on"-- you may be getting some residual localized boiling that is forcing coolant out the overflow tube, but then due to a leak in those tubes or problem with the AST cap (mad_7tist's post about pressure testing), it's not pulling the coolant back in when the engine cools, so there's dead space in the coolant system, triggering the buzzer.

 

about 60k

 

That's not good. How long does the smoke last on startup?

I'd recommend a pressure test on the cooling system.

 

When you open the thermostat to add fluid, are you also opening or releiving pressure on the AST? If you are, the the fluid may well be going into the AST.