Changing engine coolant

Try 1/4" or 3/16" ID.

 

Surgical rubber tubing might be useful: more stretchy, can accomodate wider range of spigot diameters. Maybe use in conjunction with clear vinyl tubing, for better visibility. Put a plastic barb splice at the end of vinyl tubing:



and push a short section of surgical tubing on the other side.

 

Wow, that small hu? Ok good to know.
Thanks Patrick

Also thanks for the suggestion Mendel, I have these cool adapters I got from the Qosina booth at the MDM show that have tapered barbs from 1/8 to 1/2 (IDs) on each side. Those things are so handy for getting from one size to another.

Pinback

 

Hi Guys, I am totally new here. Just got a 2008 Prius Base with 135K on it. I am hearing the swishing noises in the dash when the car is started cold. I have been reading a ton about the proper way to change the coolant, and I would like to ask...

To bleed the coolant heat storage tank, could I not just: 1) start with a full radiator; 2) open the bleed valve at the top of the storage tank; 3) run the storage tank pump; 4) keep the radiator topped off throughout this process; 5) close the bleeder valve on the storage tank when I see coolant emerge.

It seems this procedure would result in filling the tank with new coolant and a removal of all air bubbles. Just asking if this procedure would work or if there is something I am overlooking.

Also, could some one please help me understand how opening just the storage tank drain valve is sufficient to drain the radiator fluid as well? Would the pump need to run to achieve this?

 

2) There is no bleed valve at the top of the storage tank. If you think your car has one, then please take a good photo of it and post.
5) There is a drain valve at the bottom of the storage tank.

The pump does not need to run, to drain the radiator and the storage tank. Since you will learn the most from personal experience, I suggest you try my procedure of opening the storage tank drain valve first. Keep the radiator cap on the radiator so that the overflow reservoir also will drain. Then, open the radiator drain and see if any fluid comes out. Finally, open the engine drain cock and see what amount of fluid comes out.

After you do that, then you will have first-hand experience to be able to say how useful it is to open the radiator drain and the engine drain cock.

Further, if you hear air bubbling in the heater core, you need to get the air out of that part of the engine coolant loop as well, which requires running the cabin heater on MAX HEAT to promote coolant flow through the core, and revving up the engine as much as you can for 10 minutes or more. It is not sufficient to only focus on the storage tank.

 

Hi Patrick,

Thank you so much for your reply. I have been reading this thread very intently and somehow came to believe the storage tank also had a bleed valve. Could you please help me understand one more thing...

I plan to use an AirLift to change the coolant on both the engine and the inverter. For the proper procedure using an AirLift, would I follow these steps: 1) open the storage tank drain; 2) let the radiator and tank drain from the storage tank drain; 3) open the radiator drain; 4) open the engine drain; 5) close the drains; 6) draw vacuum with the AirLift; 7) introduce new coolant under vacuum through the AirLift; 8) put the cap back on the radiator.

Since I am just recently familiar with the storage tank, I am wanting to make sure I do not need to go through any procedure to make sure the AirLift is able to draw vacuum on the storage tank. I do not believe any special step should be necessary because the ability to use the tank drain to drain both radiator and tank leads me to conclude the vacuum can also pull the radiator and tank without any issue. After using the AirLift, my understanding is I will not need to jump the leads on the storage tank pump because it will share the common vacuum with the rest of the coolant system.

Am I overlooking anything?

Thanks,

Friedenmeister

 

Your procedure seems reasonable but since I haven't used the AirLift, I don't have first-hand experience to confirm that your planned work will succeed without adjustment. Good luck.

 

Patrick...
I own a 2007 Prius with 150K. Got a P1121 code and replaced the coolant control valve. Code is now gone and no pending codes. I lost about 2 qts. of coolant in the process. On the refill I got most of the coolant back in and even ran the CHS pump by jumpering the contacts in the relay bay. In the 1st go round I could hear the pump loading up and going from about 0.2 amps to 3 amps steady pumping water. Next day drove car to work with MAX HEAT on and fan at max... No Cabin Heat. That evening refilled a little more in rad. and ran CHS pump. Next day No Heat. Next day refilled a little more coolant but when I ran CHS pump now only showing 0.2 amps and sounds like not pumping water. Question... have I not done enough air purge? Is my CHS pump poss. defective? There is a TSB on the pump put out in 2008. I'm concerned about damaging CHS pump running it in "dry mode" trying to prime it. Would like to get your thoughts. Thanks, Pesca

 

Another question about the coolant to heater core loop... Is there another separate coolant pump only for the heater core? Another pump different than the CHS pump for the heater core? Thanks

 

Yes, there is a separate coolant pump for the heater core. The reason for that is the engine periodically turns off depending upon driving conditions, so the cabin heater needs some other means to keep the fluid circulating.

Run the CHRS pump only 30 seconds at a time, then give it some time to cool down before running again.

Did you verify that the cabin heater worked OK when you were refilling the engine coolant? Do you hear air bubbling in the cabin heater core? You may have to do more work purging air out of the engine coolant loop. Don't be afraid to rev up the engine for an extended period while the car is sitting on your driveway, 10 minutes or more at 3,000 RPM may be needed to get the cabin heater core filled with fluid so the heater will work. Keep an eye on the coolant level in the radiator and replenish as needed.

 

I'm preparing to replace my Coolant Heat Storage tank and engine coolant. After reading through this thread and watching several online videos, I'm still not sure of the absolute best procedure to follow, but plan to go with something along the lines of the following:

For starters, I plan to only drain through the coolant heat storage tank. It’s my understanding that I should get about 6 quarts out of this drain. Perhaps, I'll get a little more when I remove the existing coolant heat storage tank (it is dented, but still seems to be functional). I also plan to use Patrick's idea on the draining - first leaving the radiator cap on, opening only the overflow reservoir, then opening the CHRS drain. After the overflow reservoir empties, I will open the radiator cap to complete the draining.

After draining, I plan to use an air lift vacuum tool attached to the radiator neck. I found the following video that details the air lift steps. However, I have several questions related to the video that will help me figure out how much of this specific procedure to incorporate...

At 4 min 50 secs: The narrator states that the volume of coolant drawn into the system by the vacuum should match the amount of coolant drained out. Well then wouldn’t the coolant filling part of the procedure be complete? However, the mechanic then installs a radiator funnel, adds additional coolant, and revs the engine to get rid of any air pockets. Using this strategy is it possible to add too much coolant? In addition, the mechanic tops up the overflow tank.

Also, instead of revving the engine, would it be better to use the relay to fire the pump? The procedure in the video does not mention the radiator bleed valve for that last step – any thoughts?

 

1. Measure the drained coolant so you have an idea about how much to add. The idea is to replenish at least that much - you might need more if air currently is in the system.
2. It is not possible to be overfilled if the overflow reservoir level is correct. It is possible to be under filled if air is in the system.
3. If you have a problem with the vacuum technique then see if the radiator bleed valve can help.
4. The CHRS pump when manually activated, will move coolant into the tank. You need to rev the engine to move coolant through the engine and heater core.

 

Using the vacuum technique through the radiator cap, will this not force fluid through the entire system including the CHRS tank, engine, and heater core?

So revving the engine with heat on high is still a requirement? Any worries in doing damage to the hybrid battery... if I have AC on and go up a steep hill or sit at a traffic light for a long time, my battery already goes into the purple zone.

 

The vacuum technique might not fully fill the canister; you will find out when you do it. Don’t worry about revving the engine, that has no impact on the traction battery.
The point of doing all of the steps is to satisfy yourself that a complete job was done while the car is sitting on your driveway and you have a chance to remedy any problems.
Even after you think you are done, check the fluid levels both in the radiator and overflow reservoir for a few days, when the engine is cold, until the level stops dropping.

 

Since I've never done a coolant change or messed with an airlift tool, I want to make sure I've got an exact procedure on paper before I dive into this.

When you say I'll find out when I do it... how exactly will I know if the CHS tank is full after using an airlift tool? For the heater core, I understand that I should listen for a gurgling noise in the dash and when that is no longer evident, I have likely purged any air in that location. To do this the linked video says one should put the car in ready mode and rev the engine until the fan kicks on. Is it better to put the car in inspection mode first with cabin heat set to max as some have already suggested?

Also in a previous post you recommend that the engine can be revved at or more than 3,000 RPM for 10 minutes to get rid of any air in the heater core. Do you mean it is safe to rev the car constantly for 10 minutes at 3000 RPM or should this be done intermittently? If I don't hear any gurgling while revving the engine, I'm assuming revving for a full 10 minutes is not required?

I now plan to use a radiator funnel for the post airlift filling steps. Has anyone used this specific radiator funnel on a gen two Prius?

Finally, can someone ID the part number of the nicked pipe in the attached photo. The pipe is not leaking, but I figure it's a good idea to replace it when I change the coolant. The photo is from the underside of the car - the damaged pipe should be evident going to the left (directly opposite to the drain valve).

 

How to know the CHRS canister is full: based upon hearing the sound made when the CHRS pump runs.
You can rev the engine continuously at 3,000 RPM until you find the cabin heater is working and you don’t hear air bubbling. Cabin temp set to MAX HEAT. You don’t have to be in inspection mode if you are depressing the accelerator pedal.
The funnel looks like a Lisle clone. I would use the yellow Lisle funnel.
Look at the parts website from one of the Toyota dealers such as Autonation Toyota Gulf Freeway in Houston or Olathe Toyota in Kansas City.

 

So to confirm, it sounds like it would be a good idea to run the CHRS pump regardless after the airlift tool sucks in as much coolant as possible - then if the CHRS pump sounds the same as it usually sounds, then all good as far as the CHRS tank is concerned?

For the damaged pipe, I checked the autonation website and found the attached diagram of the cooling system parts. However, the diagram is confusing and I'm still not able to pinpoint the exact pipe part#.

Your suggestion about draining initially with the radiator cap still on - is this with the coolant overflow tank cap removed? Someone else suggested draining initially with both caps still on which doesn't seem like it would be the best method.

 

Yes, if the CHRS pump sound is normal then you are good.

The coolant overflow cap can be on or off, doesn’t really matter. The radiator cap must remain on if you want the overflow fluid to be sucked out.

 

Okay here is the engine coolant replacement procedure that I intend to follow - perhaps this will be also be useful to someone else who is equally inexperienced. I've incorporated several suggestions from this thread and everything is in a single post which may be helpful. I've left out the extra step I'll be doing in replacing the actual CHRS tank after draining.

Please let me know if you recommend any changes or additions. The steps I'm still not entirely sure about are related to the radiator bleed port. If the air vac tool manages to suck in close to the same amount of coolant that was drained, would I even need to bother with opening the bleed port? Is there any downside to keeping the bleed port open while activating the CHRS pump via the relay and also while revving the engine?

1) Remove all the plastic shields and driver's fender liner to gain access to the CHRS drain.

2) Disconnect the CHRS electrical connector.

3) Connect a piece of 3/16" ID tubing to the CHRS drain and route the open end into an empty container. With radiator and overflow caps still on, open the CHRS drain valve to drain.

4) When draining from step 2 is complete, open the radiator cap to drain the remaining fluid.

5) Measure the amount of drained fluid. Expecting around 6 - 6.5 quarts.

6) Close the CHRS drain valve and remove the tubing.

7) Attach an airlift tool to the radiator neck and draw the air out of the cooling system - same procedure from 3:10 - 3:55 in this video. I've been eyeing this airlift tool which is under $50 on Ebay and seems to get decent reviews.

8) Fill a container with Toyota Super Long Life Coolant (more than the amount of coolant that was drained). Continue with the airlift procedure to let the vacuum draw in as much of this coolant as possible - hopefully close the same amount as the total fluid that was drained. This step is the procedure shown in the same video from 3:54 - 4:53.

9) Remove the airlift tool and reconnect the CHRS pump electrical connector.

10) Connect a Lisle funnel like this one to the radiator neck and fill at least halfway with additional coolant.

11) Connect a piece of 3/16" ID tubing to the radiator bleeder nipple and route the open end of tubing to a spare container. Open the bleed valve with a 6mm Allen key. See 17:38 of this video.

12) Using a multi-meter, manually activate the CHRS Pump from the CHRS relay as shown in the very beginning of this video. If the CHRS pump sounds normal (and the amp reading is about 4A which indicates the pump is moving only coolant), then proceed to step 13. If the sound is noticeably different to the normal functional CHRS pump sound (and/or the amps are significantly lower than 4A), then continue to run the pump until it sounds normal. Note - do not run the pump for more than 30 seconds at a time and take short breaks between activating the pump. Monitor the fluid level in the funnel and look out for air bubbles.

13) Again, make sure the funnel is filled to at least half capacity. With the cabin air temp set to max heat and the fan speed on the highest setting, get a friend to turn the car on to ready mode and rev the engine at a constant 3000 RPM. While your friend is revving the engine, monitor the coolant level in the funnel and add more coolant if needed. When the radiator fan kicks on, check with your friend if any gurgling noises were/are evident in the dash. If the gurgling noise is not apparent (or no longer evident), your friend should cease revving the engine and turn it off. It is safe to keep revving at 3000RPM for 10 minutes straight.

14) Close the bleeder valve (13 in-lb. of torque or hand tighten) and remove the tubing. Remove the funnel and replace the radiator cap. Th Lisle funnel has a stopper so removing excess coolant should not be an issue.

15) If the engine was revved for a long time, wait until the car cools down and then top up the overflow reservoir.

16) Replace the plastic shields and fender liner.

 

I pulled the overflow tank line and capped the nipple on the filler neck.

Also pulled a vacuum a couple times after the initial drain to get old coolant from deeper recesses, then drained again. Not really necessary, but you can get more out. Just be wary of the airlift exhaust