I had an issue with the Explorer about a month ago where the radiator was leaking from a tube. Actually it was an issue ever since I did the V8 conversion but it has gotten worse over time. It got to the point that it leaked all the time. The truck never ran hot, it was just leaking.
So I ordered a new radiator and when it came in I installed it. I added coolant and started it up in the driveway to warm it up. While it was idling I noticed the temp gauge went a little higher than it normally runs so I grabbed my IR thermometer gun to check the temp. It was at 210 and it has a 195 thermostat in it. I felt the upper hose and it was warm which meant the thermostat was open but the truck just kept getting hotter. By the time I shut the truck off it had climbed to 240.
I then got under the truck to feel the bottom hose and just as I did it blew off. As soon as the hot coolant hit me I rolled out of the way but it was too late. I ended up going to urgent care and ended up with 2nd degree burns on my arms. This was about 3 weeks ago now.
Here's some progressive pictures of my arms over the first week. Luckily it didn't hurt and has healed fairly well. It's left a couple of scares but chicks dig scares so it's okay.
My wife made me wait a few days before she let me go back out to figure out why it got hot. I figured something had to have plugged either the radiator outlet or the water pump inlet but both were clear. So I filled it back up with just water and started it up again. Once again it started getting hot. This time it got up to 230 but I let it cool down for about 10 minutes before I looked at it. I put a towel over the cap and opened it so it would push fluid into the overflow tank. However, only air came out. Once the pressure was gone I removed the cap and started adding water. It took 2 gallons of water to fill the radiator (the system only holds 4).
Once I filled it up I started it back up and it stopped getting hot. For some reason the was an air pocket in the system that was keeping the water from flowing. That's the first time I've ever had that happen. I spoke to Phil about it and he said he's had that issue a lot. On some vehicles he even had to fill the system through the heater hose because of it.
The moral of this story is be careful. Working on cars can be hazardous and luckily for me I only burned my arms.