Replacing Coolant Diverter Valve

After replacing my coolant diverter valve I concluded that preserving my existing coolant and avoiding draining the system was more trouble that it was worth. Posters that prescribe hose pinch clamps to keep the coolant from leaking out are leading you down a painful path.

For you PriusChat readers planning to replace your coolant diverter valve, I offer these comments:

1. Draining the cooling system generates about 1.5 gallons of pink coolant. At 150k miles on my odometer, I elected to refill with new coolant. Several EBay suppliers are offering 2 gallons of the Toyota specified pre-diluted coolant (p/n 00272-SLLC2) for around $40 total including shipping. Zerex has an equivalent called (approximately) Asian Vehicle Coolant but I could not find it in local stores.

2. The spigot for draining coolant is underneath the coolant thermos bottle. You can reach the spigot by removing the thin plastic underside road spray shield ahead of the driver's side front wheel. You do not need to remove the entire underside spray shield, simply the left-most 12 inches of it. I removed about 4 fasteners to get to the spigot.

3. This is the most useful pearl of this posting. The least accessible hose on the coolant diverter valve is the 3rd one on the bottom. Getting this bottom hose off the valve is a bitch. My pearl is to **not** remove the third hose from the valve. Leave it on the valve. The third hose is only 18" long and terminates on the assembly that includes the drain spigot. Detach this 3rd hose from the drain spigot assembly, not the diverter valve.

4. Disconnect the 1-3/4"OD radiator hose that blocks your access to the diverter valve and push this hose to the left. Doing this might require some work with needle-nosed pliers on the hose clamp to reactivate the tiny steel tang that holds the hose clamp open when the factory attached the hose. However, with this hose out of your working area, life is easier.

5. Loosen the front 12mm screws that secure the giant inverter assembly to the frame. Use patience and WD40 removing these screws. My screws had been cross-threaded by the air wrench wielding dealership bozo that replaced my inverter coolant pump 3 years ago. Removing these screws allows you to tilt the inverter upward about 3".

Though it might require about 2 minutes of noodling over the matter, the old de-hosed valve will come out its alcove if the inverter is lifted about 3". When the Philips head screws that secure the valve to its bracket are visible to you, you are mere seconds away from getting the sucker off the car.

6. Reloading the coolant requires that you force the ICE to run continuously to warm up in your driveway. Search on Google for "Prius Inspection Mode". It's a hilarious chicken dance that forces the gas engine to run continuously.

Do not drive the car to burp bubbles from the coolant system. Do it in your driveway. The computer logs overheating codes if you burp it by driving the car.

Good luck, Gen II dudes!