The wife was driving the Blazer today and noticed that, at one point, it started to overheat. It then started to cool off, possibly because she was then at highway speeds.
At home, I checked the oil level and it looked good. I checked the coolant reservoir and found it to be very dry, with a mud like substance at the bottom. I put some water/antifreeze in and it's still very muddy.
Any ideas what this is?
A few days ago I heard a fluttering-like noise coming from the area underneath the glove box. It started and ended very quickly.
Thanks in adavance for your help!