Engine overheating

I think first I need to clarify "overheating". I may be using the term too loosely. So usually the temperature hovers right below 210. 260 is my max. I've never seen it go above the line that sits directly in the middle of the two, so 235? I'm not sure if that constitutes "overheating" or not, but it's definitely hotter than normal. Is that hot enough to warp the head gasket? And to be honest, I couldn't tell you how many times it's crept up there. Every time I drove it for about a week, then we replaced the pump. It's been about two weeks since then and it will creep up every time I don't have the heat running, unless it's early in the morning and the outside temperature isn't very high yet and it's a short trip. For example, it usually doesn't happen early in the morning on my way to work, but will happen without fail in the afternoons while I'm driving home and the sun is hottest. I'm not sure about the fan but I will check that when I leave work today. Thank you for the information!

Sorry for the delayed response. I only see 1 fan, it's pretty large and appears to be dependent on a belt. Is that the one? If so, it's spinning nonstop. The thermostat is 160°. Duralast 37960.

Got a new thermostat this morning. We ran all of the suggested tests for the gasket (except the chemical kit) and so far so good! I wish the guys at our parts store knew as much as you. I think we'd have been saved a lot of trouble. We'll swap the thermostat today and let you know how it goes!