Now that the radiator is out, and your belt is off, and you’ve replaced the tensioner, it’s time to replace the other parts on the front of the engine. A couple of these are hard to get to, but that’s ok. New parts:
11. Next up is the idler pulley. This one is ultra easy. By the way, if you want to clean some of these surfaces, feel free. Just don’t scrub them and score them up so much that you start leaking coolant or something. I read that 14mm bolts take 35 ft lbs, and 12mm bolts take 17 ft lbs on the front of this engine.
12. Fan pulley bracket. The pulley cover comes right off. From there, it gets fun.

The bracket is held on by three 12mm bolts and one 14mm bolt. One of the 12mm bolts is what makes this a little complicated. There are some hardlines that run across the face of the engine here. You can see two 10mm bolts that hold these hardlines in place. But, there is a third. It faces sideways toward the bottom of the engine, looking straight at the compressor. Some people remove the compressor. I did not. I found that by removing the top two 10mm bracket bolts, LOOSENING the bottom one, and taking the hard lines out of the hoses, I was able to move the hardlines enough to get to that 12mm bolt. Here is everything in one pic:
12a. Remove the two 10mm bolts circled in green.
12b. Remove the hose off the end circled in orange.
12c. Remove the hardlines from their hoses (yellow).
12d. With an open end 10mm wrench, loosen BUT DO NOT REMOVE the 10mm bolt facing the compressor pulley (red arrow).
12e. You can now pull the hardlines toward you and to your right to get to the difficult-to-reach 12mm bolt behind the hardlines (red circle).
12f. Install the new fan pulley bracket. 12mm bolts get 17 ft lbs; 14mm bolt gets 35 ft lbs. Again the pulley cover just slides back on and is held in place when you reinstall the fan.
12g. DO NOT reinstall the hardlines. You’ll want them out of the way for the water pump as well. Moving on!
13. Water pump—FIRST THING: trace the water pump on a piece of cardboard (the Toyota box it came in is fine), and mark the locations of all the bolts.
There are two 14mm; the rest are 12mm, including three 12mm bolts that hold the thermostat housing to the face of the water pump. Stick your bolts through the cardboard as you remove the old water pump. There are a couple hoses you may need to move to get to it. It also helps to remove the air box at the throttle body.
13a. Loosen the Phillips head hose clamp on the air box. There are a couple small hoses and a wire to remove. Undo the latches to get to the air filter. Remove the entire air box.
13b. Loosen four 10mm bolts at the throttle body. You can leave them in though. There are two hoses that need to come off the block as well.
13c. Remove the four 12mm bolts for the water pump pulley.
Now you should be able to reach everything pretty well on the water pump. I took it off with the thermostat basically in one piece. Put your new thermostat on. (Enjoy that this is super easy.) The three 12mm bolts that hold the thermostat housing to the water pump also go through the block. Install the water pump bolts first. I torqued mine down in a pattern like I was installing a tire. 17 ft lbs for the 12mm; 35 ft lbs for the 14mm. Then put the thermostat housing on with your new thermostat mounted (make sure your gaskets are in place! One black, one orange). Reinstall the water pump pulley with four 12mm bolts.
At this point, you have your new thermostat, water pump, idler pulley, fan pulley bracket, and tensioner (which is locked back) installed.
Before we install the new radiator, we need to put the front of your engine back together.
14. Reinstall ALL hoses and hose clamps. Tighten the sideways facing 10mm bolt we loosened (but did not remove) in step 12d. Reinstall the other two 10mm bolts that hold those hardlines to the front of the engine. Refer to the picture in step 12 if needed. Put your air box back together at the throttle body. Reattach hoses and clamps. Double check that everything looks good. You should have all new parts installed with all bolts properly torqued and hose clamps reinstalled.
15. Install your serpentine belt. Double and triple check belt path. Man this is so easy with the tensioner locked back. Here’s a diagram, which is in several other places on the forum.
16. Now unlock your tensioner, and remove the Allen key. Your serp belt is set.
17. Install new radiator. It slides straight down. I held it in place and started the easiest (upper passenger) of the four 12mm bolts. Get your extensions back out to install the two lower bolts. Pull that panel back out of the way to get to the upper driver side bolt. Tighten those four bolts up.
17a. Reinstall the two oil lines at the bottom of the radiator.
18. Reinstall fan and fan shroud. Kind of awkward, but certainly doable. Holding the shroud in your left hand and the fan in the shroud in your right hand, slide them together down the backside of the radiator. Your first concern is getting a couple 12mm nuts onto the fan pulley so it doesn’t fall while you’re reinstalling the shroud. Once that’s set, time to put the shroud back together.
18a. Make sure the lower corners of the shroud are sitting in their slots on the radiator frame. You’ll need to do this from underneath. Then, loosely reinstall the 12mm bolts at the top corners of the shroud.
18b. Reinstall the two 10mm bracket bolts toward the lower passenger side of the shroud. And if you didn’t break that plastic collar, reinstall that, too.
18c. Reinstall upper overflow hose on shroud.
18d. Once everything is put together on the shroud, tighten those 12mm bolts at the upper corners.
19. We’re getting close! Install new upper and lower radiator hoses. Make sure clamps are placed properly.
20a. Add coolant to the radiator. Do it slowly. (Mine took about 1.5 gal before it started overflowing).
20b. Add coolant to overflow reservoir. I went to the F line.
20c. Start the truck. Let it fully warm up, idling at 2k rpm. Once fully warmed up, turn the truck off.
20d. Take a heavy towel, and turn the cap until steam hisses out. It’s now safe to add more coolant.
You might repeat steps 20a/c/d two or three times. This is how I “burp” the system.
You probably don’t need to repeat step 20b. The coolant you added to the overflow reservoir won’t be sucked back into the radiator until you let the system cool itself down without opening the cap. I have been watching temps on the Fusion app on my phone using a Veepeak Bluetooth OBD reader.
Once you’re sure you’ve got no leaks, reinstall your skids and engine covers (if you’re driving an LX).