Last night i finally decided to take 2j sc400 home which is rougly a 60 mile trip. With about 10 miles left, i see the temp gauge start rising to hot, then slow fell back to normal operating temp and quickly rose all the way back up. I got off the highway to stop and steam was pouring out from somewhere around the neck of the radiator hose, i havent had the chance to see yet if it cracked but doesnt seem that way. i let the car sit for 20 minutes, poured some water in the radiator and drove it home 10 miles and it didnt over heat again. I wasnt expecting this..so WTF? i did check the radiator cap and it seems like the guy that did the swap didnt use the right cap because there isnt a spring on the bottom of it. So today after work, if my cuz has time im taking the car to his shop to have him check it out, check the radiator and do a compression test. The car does idle fine and sounds fine but just to be on the safe side. Do you guys recommend anything else or have any insight?

 

bleed out the coolant again and replace the radiator cap. is the radiator a stock radiator or an aftermarket? Both my co workers had problems with bad radiator caps with their aftermarket radiators and found that replacing it with the stock cap did the trick.

 

It's also possible that your thermostat is going on the fritz.