Rep Power: 0

Experiencing some overheating with my beater, my car started to overheat after coming off a 1 hour trip on the interstate, coming off the interstate 3 mins in i saw my temp go up, was able to make it home after the car cooled down. That next day I replaced the thermostat, rad cap, flushed coolant and car was still overheating (only when driving on the interstate for more than 10 mins and coming off). I forgot to burp after I replaced the thermostat so I burped it and that burp lasted me a good 4 days of working the engine before it began to overheat again. So i burped it one more time and it lasted me another 3 days i couldnt figure out what was wrong with it so i burped it again (I would also notice coolant would spew out the rad cap each time it overheated would be on the inside of the hood), and now 2 days ago my radiators plastic gasket blew so i need to replace my whole rad. Had to get the POS towed and just dont know what's wrong with it.Also would like to add that my head gasket was replaced in 2020 and i dont lose a drop of coolant

Things i've done
\- Replaced thermostat
\- Made sure both fans work
\- Flushed Coolant (Used hose method)
\- Replaced rad cap
\- Head gasket combustion tester (color never changed)
\- Coolant air burps
\- No frothyness on the oil dipstick
\- No residue on the bottom of rad cap
\- Made sure theres no hose leaks
\- Checked spark plugs for gunk or discoloration
\- Heater works perfectly but i noticed when my car would overheat it would turn cold so i have a feeling it could be my water pump....


My guess is theres too much air being forced in the cooling system when i drive at high speeds so my HG is blown, but it only overheats coming off the interstate wouldnt my car overheat right on the interstate? Like when my radiator blew it only happened once i got off the interstate and was idle.

 
Rep Power: 221

Try the water pump, but at this point with the multiple overheats the headgasket mught be blown again

 
Rep Power: 223

Are you talking about the coolant reservoir cap? Radiator cap definitely isn't plastic.

The only thing that would cause you to need to burp air out is a coolant leak or a leaking head gasket. Both would allow air into the cooling system. If there's no coolant leak, you have a bad head gasket. And coolant overflowing out the top of the reservoir does not count as a leak, that is instead a side effect of a failing head gasket.

Greater speeds on the interstate means more airflow and greater water pump flow, better engine cooling even with the air inside the system. As soon as you get off the interstate, a lot less airflow and coolant flow, a lot less cooling. You would surely see overheating on the interstate if you drove long enough.