Here are the symptoms/conditions I'm having:

1. Coolant overflows into overflow container only under boost and load at high RPMs. Idling or revving in neutral doesn't usually cause overflow.

2. No white smoke on startup

3. No hard start...starts in 2-3 revolultions

4. Radiator cap chaned to mazda factory cap...no improvement.

5. Thermostat replaced...no improvement

6. 100 psi on all rotor faces

7. New water pump

8. After engine cools, SOME water is sucked back up out of the overflow, but not all.


So WTF is up with this thing? No classic symptoms of blown coolant seal, no overflow unless its being driven hard. Even if I try the geyser test (crank with radiator cap off), I don't get water shooting up. Any ideas? Could this still be a blown coolant seal?

-Joe

 

maybe its normal

(but don't take my word on it.. I don't know much about these cars. yet )

 

Does it over heat?

 

I'm sure it would once it hocks enough coolant up. It can easily fill the overflow container during hard driving, and after that, the coolant just overflows the overflow cantainer and gets sprayed around the engine bay. Even though I haven't let it get to the point of overheating, I'm sure it would with this much coolant loss.

-Joe

 

Might be a rad on the verge of getting clogged up.

Could also be a pinhole in your overflow tank/cap/tubing...

 

I've wondered if it is the radiator. How would I check for a clogged radiator though? Also, this may be a stupid question, but how would a hole in the overflow tank/cap/tubing cause this? I can see how it would cause coolant to not be drawn back into the coolant system after the engine is shut off, but could this cause the overflow???

-Joe

 

how big would you consider a pin hole anyways???

 

^ A HOLE, now hold your breath for this...





...THE SIZE OF A PIN!!!!

 

A hole in the overflow wouldn't do anything. It gets drawn back in through a tube that goes to the bottom.

 

I'd guess it's an almost clogged radiator. By some radiator flush stuff and see how it goes.

 

A hole in the tube that is at a part not submerged in water could do something.

 

All you need is a pinhole to kill your vac. Wow, I didn't know some cars had an overflow hose that ran from the bottom of the tank back to the rad. Mine sure as hell doesn't

To see if the rad is clogging, pull the drain plug, let her drain, leave the drain plug out, then pour a gallon of water into the rad neck as fast as you can (but still controlling flow) from a milk jug type container. If you can get her to overflow while you're pouring, something is wrong...