Been seeing some bubbles in the reservoir after driving. Car does not over heat nor does it lose coolant or push coolant out. I was thinking it could be the rad cap as it’s not Oem, I’ve replaced the thermostat earlier in the year with an oem 180 from Mazda.
Strangely on startup without driving I don’t get any bubbles after a drive they come back. Not fizzy type bubbles but burp style bubbles.
Anyone else experienced this?