I've checked and I don't have any leaks, but I do notice that my antifreeze reservoir keeps filling up. I figured maybe something's clogged in there, so I did a radiator flush, but now it seems like the same problem.

Anyone ever experience this before? Know what the problem could be?

Hole in the radiator?

No, there are no leaks.

broken rad cap ? if the pressure isnt right it wont suck fluid from the overfill

How much do you think a radiator cap would be, i think i need one.

Could it be a thermostat problem?

Mine low fluid light does the same thing...It is porbly my radiator cap. I bought a new one but havent put it in yet https://www.nopistons.com/forums/pub..._DIR#>/dry.png ...I should get on that.



New cap is like 10-15 bucks from mazdatrix I think

Just go to an auto parts store for your radiator cap. As long as it is the right pressure. No reason to buy a silly mazdatrix one, your just spending more money.



Also check your coolant sensor. It should be right on the radiator itself if you have the stock radiator. It could also be the thermostat. I thought the thermostat was just suppose to rush more coolant if the temperature levels get too hot? Could also replace that too.

Sounds like either the radiator cap has a weak spring (they do wear out, just like most of the rest of the cooling system), or the dreaded coolant seal. If the radiator cap is questionable, go spend a couple of bucks. Hopefully it's not the coolant seal.

Where's the coolant seal? Where do I look to check that?