My 2004 Honda Civic has been having some puzzling cooling system issues. The car would slowly start to overheat, giving me enough time to pull over and shut the car off with one exception. When the hood was lifted, it was evident that coolant had built up pressure resulting in coolant blowing out of the reservoir. It's worth noting that the heat in my car would become cold, there would be an awful burning smell, then the gauge would start to creep up. Occasionally, the temperature would return back to normal before getting three quarters of the way up to maxing out the gauges. My SO is a hobby mechanic. He has replace the following parts (in order): both radiator hoses, thermostat, cooling fan fuse, and the radiator (which did have some holes in it). I also have new radiator and reservoir caps. There is no coolant in the oil to indicate that the head gasket is bad, but that's the issue that we are leaning towards. The professional mechanic hasnt physically looked at the car, but he seems to want to replace the water pump, the head gasket, and the timing chain (even though that was done fairly recently) based off of all of this information. Does this seem like a reasonable course of action? Does anyone have any other ideas/advice? I bought this car off of my SO's grandparents after a relative passed away. It has about 140000 miles on it, 4000 of which I have put on it since purchasing it in November.