After I heat the engine up and shut it off lately I noticed that the radiator burps itself. Is this normal? I've never noticed it before.I'm pretty sure it is the original radiator. Could it have a small leak and is sucking in air from the overflow tank? New radiator is on my future upgrade list.

 

its possible there is a leak, although it could be anywhere in the cooling system. it also could be that the cap is failing or the thermostat is bad too.

 

start with the cap. its cheap and probly needs to be replaced anyway lol

 

I would do the cap and thermostat, and mazda only of course.

 

if the cap is holding pressure at high temp, why replace it. start with the engine with the rad cap off and while the engine is idling, squeeze the hose to burp the radiator, then slowly fill it with coolant and reinstall the rad cap

 

The cap still feels springy, but firm. I have never replaced the T stat and have owned the car for 3.5 years/ 8000 miles. I think the radiator may have a pinhole leak. Been meaning to replace it for some time now.

 

Do you notice anti freeze on the ground after driving and parking it?

 

Do a cooling system pressure test. That way you can narrow down what exactly is leaking. There is no sense in replacing things and throwing money at hunches that may or may not be the issue.

 

There are no noticeable coolant puddles. Doubt it is an engine seal or manifold o ring as the car starts easily and smoke free. My next plan for the car was the coolant system. New radiator, new T stat, new cap, flush, refill... I'll probably even splurge for some Racing beat silicon hoses!

 

If your going to throw money at it in a preventive manner dont' forget the water pump itself ...