Radiator Issues

[MCATDT]

I posted earlier about a gurgling radiator. I have swapped the cap 3 times, pressure tested the cap and system and did the sniff test to check for exhaust fumes in the cooling system, all tested good. I just changed the thermostat as well thinking maybe air was getting in there and the system is still gurgling. I think the previous owner changed the radiator and wondering if they used the wrong one or the caps I'm purchasing are not compatible. The radiator is stamped PA66-GF30 on the top. I really feel like the caps are just a bit loose but not sure what I would need or if there is a way to tighten up the caps on the radiator neck.

 

[Link]

Is the radiator building pressure when hot?

Do you have AC? The AC in a Jeep TJ will make a hissing or could be described as a gurgling sound as it runs. Since the orifice tube is up front and not near the firewall as in many vehicles, it hisses or gurgles much louder than some other vehicles and does so up near the radiator.