c-15 water temp

When's the last time you washed the radiator out? Likely has dirt clogging the fins. Water hose and use a pesticide pump sprayer to shoot some simple green or some other mild surfacant/detergent in there. Do NOT use a high pressure washer. Garden hose low press only..

 

I wash mine out every couple of months just routine maintenance it's a good practice.

 

Had the same problem for a few months, aired out tge radiator and it was fine after that for a week or so; ended up getting a new radiator cuz the old one had a hole in it but it fixed the issue!
Try AIRING out your radiator; dont use water cuz dust and bugs can stick to it.