I checked my radiator and coolant reservoir and it is not empty of antifreeze. There are spots around the reservoir and radiator where it appears to have coolant dry up from a leak. This might have oozed out a little when the coolant bubbles up when the engine heats up. If I do have a tiny leak, I don't know how to test to find where it could be. I also bought a new radiator cap and also a new reservoir cap thinking that it would stop the leak if the source is from the top of the radiator and reservoir. I also had the thermostat replaced; however, the problem still remains.
I noticed that the temperature spikes up after 40 + minutes of driving. The temperature is fine when I'm on the highway but the temperature begins to climb as soon as I reach the streets or during stop-and-go traffic. My fan is working fine so I doubt that is what is causing my temperature to rise. I also don't feel anything different from the way the engine runs. I am not losing power or anything malicious like that.
Extra details: 2005 Honda Civic LX Sedan with 141,000 miles on it.
Read more: What is causing my 2005 Honda Civic to overheat?
