coolant loss

[awfc3s]

So here's what's up. I'm losing coolant but not burning it. The coolant is going to the over flow tank but will not return to the engine. Thinking i might need to replace the hoses but not entirely sure yet. Any insight will be more than appreciated.

[Project#7]

It could be the water pump, hoses, thermostat, a clogged radiator, or air in the system that needs to be bled out.

I'm voting air.(But i could be wrong)

Has the coolant ever gotten real low? If so it could be air. There is a bleed screw on the thermastat housing.

Check out this website for good info from Mazda Tech Manuals + pretty pictures with locations 
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Snippit
It is recommended to change engine coolant every 30,000 miles. The refilling has to be properly done in order to avoid the introduction of air into the system. The correct procedure is as follows (assuming the radiator drain plug and engine drain plug are in place):

* place heater control to maximum heat
* remove the radiator bleeder plug
* remove filler cap
* add 50/50 mixture of ethylene glycol and (distilled) water into the filler neck (where the filler cap screws in)
* once fluid starts coming out through the radiator bleeder hole, go into a "add and hold" mode (add a little and then wait a little) until fluid comes out as soon as you put it in
* screw in radiator bleeder plug
* fill the reservoir with coolant
* start engine and let it run until the thermostat opens (upper radiator hose is hot to the touch)
* add coolant (as necessary) into the filler neck
* screw in filler cap

Good Luck!
-Project#7

[awfc3s]

Alrighty here's whats up... i had to write my first post rather quick cause i was on my phone and at work lol. so i think that i have most of the air out of the system if not all of it. did this a couple weeks ago cause i noticed my upper radiator hose was not getting solid. anyways i always fill up the coolant the way its stated in the FSM. Im thinking the culprit might be that hose from the radiator cap to the overflow. it seems really soft. Now also these are the original factory hoses on here so i know for a fact that they need to be replaced (just too long of a time on there) Im wondering if it could be my water pump because when i first did the swap i had a high pitched whine coming from the water pump when i had the clutch fan on (converted to e fan) who knows im just hoping its not a coolant seal (on knees praying) OOO forgot to ad that i have a new thermostat cap (just like radiator cap) cause i thought that would definitely help out the situation but the other cap (on the radiator itself) is strange... ive never seen one on anyone elses 7... it has a bleeder valve on top and sometimes coolant comes out of that bleeder valve. anyways i feel like im rambling on and this might not make any sense but if anyone has any idea please let me know... otherwise im going to just end up replacing everything which might be a good idea anyways. (waterpump, hoses, radiator, thermo, caps)

P.s. if anyone has said parts listed above let me know ;-)

~Andrew

Whewww 

[Kentetsu]

If that strange radiator cap is not OEM, then the first thing I would do is replace it.  Is this the cap that would control uptake of the fluid while cooling down?

[awfc3s]

I believe so. Its the cap that's directly on the radiator.

[Kentetsu]

Yep, I think that would be the place to start.  Good luck...

[ITSWILL]

Not sure if this is the same problem. On my ls1 car, I get overflow into the tank and it doesn't seem to ever go back into the radiator.  I tried oem caps, higher pressure caps and higher pressure caps with the vent lever.  No difference.  Also I spew a bit of coolant out of the cap sometimes as well.  I highly doubt my overflow tube is clogged as it is only a few months old.

Realistically now that I think about it I cant see why or how even it would flow back into the radiator as the radiator cap is more of a one way valve.

So I think the maybe what we should focus on is why are we overflowing in the first place.  Could be 2 different reasons.

[Kentetsu]

Some overflow is normal.  As the coolant heats up, it expands beyond the capacity of the radiator and needs somewhere to go (overflow bottle).  Then, as it cools down and contracts, it should draw the fluid from the overflow bottle back into the radiator.  Which is why I suggested getting an OEM radiator cap.

I suppose another possibility would be if there was a leak in the hose leading to the overflow.  Then it might draw air into the system rather than the coolant.

Another possibility would be if the tube that is attached to the cap on the overflow bottle was missing, leaking, or not reaching down into the bottle far enough.  If that tube is not present (this is the one that leads down into the depths of the bottle) then it would not be able to siphon the fluid back into the radiator.

Good luck....

[awfc3s]

Got the new radiator cap on and so far levels arw consistent. Hopefully it will stay that way.

[ITSWILL]

did you get a mazda cap? I have tried the others but maybe a new Mazda cap would help me if it has helped you?

[awfc3s]

Mazda cap for sure.

[toplessFC3Sman]

Yea, a new cap solved it for me; I needed a new one for the thermostat neck, and since I couldn't find a mazda-type, i got a regular one with a higher pressure rating, and then took a spring that was a little bit wider than the one for the sealing plunger (for an overflow-type location) and threaded it between the plunger & the cap to increase the pressure even further.

[ITSWILL]

im gunna have to give that a try.

[toplessFC3Sman]

Just make sure that if you do the stuff to increase the pressure rating for the one cap, that you only do it for the cap on the thermo neck, not the one on the radiator with the overflow tube.  The cap controlling the overflow should be at the normal pressure rating, since you aren't trying to increase the pressure in the system; all you're trying to do is make sure that the overflow cap is opening & bleeding pressure before the thermo neck cap starts to open

[ITSWILL]

I have an ls1 so no second cap just the one on the koyo.