Ok so i just filled and bled my cooling system after replacing the radiator, ast, lines, overflow bottle. I drove it around amd parked then let it sit over night. I checked the coolant amd it was low so i topped it off. I drove the car to work and checked the level at lunch. It was low so i topped it off as well as my overflow bottle. I drove it home and will check it in the morning but im 99.9% sure it will be low. Anyway my question is where is all my expensive fl22 disappearing too?!?! No way there is this much air to where im putting a cup or so in it each top off. No white smoke out the exhaust but could i still be burning coolant? I have no leaks either. When i pressure test it whats the max psi i should go to? This motor is new unit shipped from mazda. It has barely 1000 miles on it. Are these motors thay fragile they fail so soon?? The coolant is ninja vanishing.

 

Not to say you absolutely don't have a coolant seal issue, but...
When I drain and refill my coolant and vent it out the coolant hose at the rear of the UIM while filling, it still takes several drives and 1/2-cup+ top-ups to get the level to stabilize. It's done this every time I refill since I bought it in 1992. A few times it's been low enough to trigger the annoying and insistent low-coolant beeeeeeeeeeeeeep. So give it a little time before you worry too much.

 

Agreed. Happens to me every time also. Give it some time.
Mike

 

If your overflow reservoir wasn't full to begin with, I could see it allowing a little air into the system as well. Also, if you haven't already, run the heater for a few minutes before you top off again. If your low-coolant buzzer isn't going off, you're not seeing temp spikes and you're not hearing boiling sounds after shut down you're fine.

 

What they said.

 

 

If you're not using a lisle funnel, have the heater on full power and the overflow half full then what you have happening is going to happen. If you continue doing what you're doing then eventually it will be full. If you have an external water temp gauge then I suggest unplugging the fans, waiting for the temp to get around 95c and then shut the car off with the lisle attached. The thermostat will be at full open and a VERY large amount of whatever air is in there absolutely will be evacuated. This is the method I use on all my cars and it's a 100% success rate. Only ever need to do a bleed once.

 

Need the Lisle funnel.

 

It seems like it certainly would make filling easier, but I've gotten along w/o it for 26 years...

 

Alright guys, good news. I havent had to add collant in a few drive cycles now. I think i really just had that much air in the system. But since i have cooling system gurus subscribed to this thread. I have to ask. How do you know if your thermostat is bad. Does it get stuck open or closed? Im sure open but when i replaced my coolant the last bonehead who owned the car had muddy chocolate milk looking water in the car and im sure the thermostat lost alot of its life during this time...

 

Muddy chocolate milk coolant means there may be oil in the water - that's not a good sign.

 

 

Same for me. Just disconnect the throttle body coolant line, and the air goes out when you fill it.

 

I had an older thermostat fail on my recent rebuild because it sat for two years. It would start to open 10 degrees after it should and never fully opened even with boiling water at 215-220 degrees. Take it out and check it out in a pot of water. Heat the water on the stove with the thermostat in the water and use a temperature gun and keeping watching as the water heats up. Full open is around an inch or so inward movement.
Mike