2008 /2nd Gen : Major Maintenance on Cooling System

2008/ 2nd Gen Prius with 168K purchased back in '08 with 17K miles. In its life I've done regular oil changes/filters, serpentine belt and 12 volt batteries plus tires as needed. At 92K miles, I took it in for the inverter pump recall to my local Toyota Dealer. My thoughts were when I retire I would just sell the car, but I found I liked it too much to sell. I recently got a check engine light (I read code 1116/1121 using my Autel 319 code reader)and after discovering Prius Chat and all the videos and youtube videos I decided to do some major cooling system maintenance. All parts and fluid are OEM Toyota (except the belt) (see photo 8).

My thoughts were to do as much maintenance as I thought necessary and preventative to take the Prius maybe another 100K and beyond. My goal here is not to go into all the details for the job, but to comment on my experience(s)....you'll find on Prius Chat and Youtube that there are numerous videos of folks before me that have done an outstanding job of video'ing and giving details I found necessary. Let me say I reviewed these videos multiple times to ensure I had adequate knowledge prior to turning the first bolt.
I have attached photos below. I hope the following helps out anyone with a modicum of mechanical aptitude to take on this job. It's not that hard after doing a thorough review. Good Luck!

The order I decided to do things:
1. Drain the inverter side coolant and replace the inverter coolant pump (behind left headlight)
2. Refill inverter side with fresh Toyota SLLC coolant (4 quarts)

3. Drain the engine block side coolant and replace the coolant control valve (behind left headlight and next to the inverter pump previously replaced
4. Remove and replace the engine water pump and serpentine belt and install new pump/gasket
5. Remove and replace thermostat & gasket
6. Refill engine block side with fresh Toyota SLLC coolant (about 7.5 quarts).
7. Test drive short distances over the next couple days and refill until level stays full.
*Step #7 most important that continuing checks are made as the level will go down.

Let's get started. Let me add that a day before I started I hit all the bolts, screws and hose clamps I could reach with penetrating oil. I also removed the road panels and wheel skirts a day prior to minimize the length of time to do the valve/pumps and coolant change the next day. I would suggest you try to video how you remove these panels/skirts and take note what screws/bolts go where or you'll take forever, like I did, to figure out this puzzle! There is not much on youtube about this.
I'll begin in the numbered order above:

1. Draining inverter side was quick and easy. I removed the left side headlight and was able to access the inverter pump very easily. Remove the mount, hose clamps and re-install. Suggest mounting new pump first then attach hose and clamps. (1hour) (see photo 1 and 2)
2. Refilled inverter side. Be sure to follow the video and attach your clear hose from the bleeder valve to the inverter reservoir. When coolant flows out the bleeder and no bubbles exist you are basically finished.

3. On the engine block side, I opened the CHRS (coolant heat recovery system) stopcock valve, the radiator stopcock and the bleeder valve (just open it about 4 turns) (uses a 7mm allen wrench) and drained about 7.25 quarts of coolant. It helped to squeeze the radiator hoses. Next, I removed the coolant control valve (photo 3) (this caused my check engine light to come on with code 1121). I would suggest removing the two upper hose clamps first then remove the two bolts that attach the pump to the frame next so you can rotate the pump and get it into a position to remove the bottom hose clamp. Do all the work while the headlight is removed as you have great access to it. Now, install your new pump and re-attach the 3 hoses. Use plenty of lubricant and muscle here as these clamps are tough. Have a selection of pliers and I even purchased a long pair of hose clamp removal pliers from Home Depot that really helped reach some of the clamps without having to stick your arm down in the tight spaces.
4. Now it's time to remove the front right passenger side tire. You'll have direct access to the water pump and belt from here. Next I loosened the belt tensioner bolt (from above) then (from the wheel well) I removed the serpentine belt and 3 bolts holding the water pump pulley on...I could easily get my small socket wrench on all the bolts. I then removed the 2 nuts and 3 bolts that hold the water pump on and the pump and gasket came out easily. I cleaned the mounting plate and installed the new metal gasket and pump (see photo 4-7) tightening the bolts using my socket wrench. I don't have a torque wrench so I trust I tightened them adequately, but use the torque wrench if you have one. Next, I installed the water pump pulley (3 bolts)and the serpentine belt. I then tightened the belt using my socket wrench occasionally checking the 1/2" play in the belt you want.
5. Thermostat and rubber washer. Easy job but be sure you remove the hose clamp and hose before trying to remove the 2 bolts holding the plastic hose fitting onto the mount. Otherwise, you cannot get your socket over the bolts. Pull the hose off and you'll see the thermostat sitting in the hole of the engine block. It easily comes out, replace with new thermostat and gasket, and re-install.
6. With the radiator cap off and using a long funnel that seals the opening, I removed the radiator reservoir plastic cap and opened(4 turns) the engine block bleed valve (using a 7mm allen wrench) I was able to easily get 4 quarts of fresh coolant in. I knew that there should be around 7 quarts in there so I attempted to run the CHR pump using the method in the videos, but I could not get mine to run. Therefore, I ran the engine about 3 times in short bursts and put 2 quarts more in. I felt there was enough coolant in the system now so I ran the engine continuously with the heater on max hot and fan on High (steps you take inside the vehicle as seen on youtube) and was able to get another 1quart in. This takes some time folks. Be sure you follow the videos. Connect your clear tube from the bleeder valve to the plastic radiator reservoir and you'll see coolant flow all the way to the reservoir....eventually....it takes a while.
6. When the level doesn't go down anymore and there are no leaks, it's time to re-install the headlight, bumper trim, and road panels/wheel skirts. Now, take it for a SHORT test drive around the block (I noticed my 'check engine' light had gone out). Come home, wait till it cools enough to check the level. Mine had pulled about half the plastic radiator reservoir coolant into the system so I filled it back up and topped off the level as seen through the radiator cap. I test drove it again, about twice more, until the level stayed full. I then took it up to 50 mph with the heater on max hot and fan speed on High for about 5 miles....came home....let it cool.....and checked level. The plastic radiator reservoir stayed full but the level down the radiator cap was down a bit. Topped it off and it has not gone down since.
I am going to continue checking the level after every drive for the next couple days. If it doesn't drop any and there are no leaks, I'll consider the job done.

Stoner

 

Thank you. I hope it helps somebody else.

 

I have not received many responses so I am wondering if maybe I posted this in the wrong place on Prius Chat?
Thoughts?
Stoner