Well, after replacing my thermostat I decided to do a write up on it. If you are needing to replace your thermostat, I highly recommend doing it yourself. It is easy to do, and very cheap. Note: This is for the 4.0 OHV, not SOHC First, a general disclaimer: I am not a Ford engineer, and do not work for Ford. Anything that you do, you do at your own risk. Now to start. It should take about an hour to complete this, but giving yourself plenty of time is the first step. The tools I used are very common, and can be found just about anywhere. Before you start, drain all of your coolant out of the car. This will make your life a lot easier down the road. Tools used: 3/8" Drive ratchet 3/8" 2" drive extender 3/8" to 1/4" drive reducer 1/4" drive ratchet 10mm socket 8mm socket Flathead screwdriver (not pictured) Parts needed: Thermostat New coolant Now, where is the thermostat located? It is on the end of the hose going to both the engine block and the radiator. It is where the hose bolts onto the block. First off: The intake needs to go. Take off the latch for the filter, unplug the 2 plugs in the intake, and pull the vacuum line out. Now, unscrew the hose clamp with the flathead screwdriver, and remove intake. Now there is that throttle cable cover there. That needs to be removed. Take you 8mm socket, and remove the 2 bolts holding that on. After that is removed, remove the 3 bolts holding the hose on. These use the 10mm socket. It will take some experimentation with the different extenders/ratchets I have listed, but it can be done with just that. When you are loosening up the bolts and removing the hose, be prepared for coolant to leak from there. Have something underneath the front of the truck to catch it, Either an oil change pan or just some old towels. Once removed, you will see this: Please note that the thermostat shown in this picture is actually the new one, yours will not look that nice. It will also be wedged in there solid, and take some wiggling to remove. When you place in the new one, be sure it is aligned the same way, and rotated the same way as the last one. Now, put the hose back, and tighten in the 3 bolts. Then re-attach the throttle cable cover. Now put the intake back on. Be sure to re-attach both sensor plugs, and also the vacuum line. Now, refill the coolant and burp the system. You have now successfully changed your thermostat. Take it for a drive, then check for any leaks. This is the old thermostat. Note how the gasket around it is worn and chipping. Just remember, replacing your thermostat is easy to do yourself, and a lot cheaper too. Just take your time, and everything should go fine! If I have left anything out that you think should be added, be sure to add it or let me know!