My guess is that you have (2) problems. It's impossible that your intake temp. is "30 degrees always"(I'll assume celsius/ 86deg. fahrenheit), unless your temp. sensor or monitoring device has failed. How to know whether the coolant is circulating is a good question. Some of us here have, in addition to coolant isolation, installed either an inline fill canister that you can actually see the coolant movement, or a supercooler(see one @ NeedsWings.com)that have a cap to open up and see the fill. This isn't proof positive either, because if the pump is intermittent, or just not pumping adequate volume, well, you get the idea. I would just change the pump like hundreds of us have had to do. You can find that @ NeedsWings also.