Coolant Bleeding

1. Park on relatively even ground
2. Attach no-spill coolant funnel
3. Fill funnel to half-full
4. Make sure HVAC/Heat/Fan is OFF
5. Key ON, Engine ON
6. Watch the coolant in the funnel
7. Add coolant as needed
8. Watch for bubbles
9. Use a steering wheel lock, stick, 2x4, some sort of long or heavy object and use it to depress the accelerator pedal and give the engine some load (2000rpm - 3000rpm is what I go for)
10. Add coolant as needed
11. Watch for bubbles
12. Repeat steps 10 - 11 until satisfied
13. Wait for fan to turn on
14. Release the accelerator pedal
15. Repeat steps 10 - 11 until satisfied
16. Wait for fan to turn on
17. Done!

What YOU Can Do

1. Go for a long drive
2. Fan OFF, Heat OFF, HVAC OFF
3. Attempt to listen for the fan to turn on
4. Come back home
5. Key ON, Engine ON
6. Fan OFF, Heat OFF, HVAC OFF
7. Open the hood
8. Wait for the fan to turn on
9. Done!

 

And do a voltage check of the fluid for the acidity.

 

Car idling from cold in the driveway with the hood up- watch the fans and keep checking the temp gauge to make sure you don't overheat during this test- after the engine goes into operating temperature the fans should cycle on and off as needed to keep the engine from getting hotter than just operating temperature. If the fans never come on and the needle raises upward above the middle and doesn't come down, shut the engine off. Swap the fan relays and repeat the test. If the fans operate correctly, the relay swapped out was bad and needs replacing. Since the fans run with the AC on you know they are good.

I've never had Toyota fans run after the engine was off in my '86 Corolla, Camry, '98 Corolla, '10 Corolla or '05 Camry. Review your owner's maual for your Toyota and its fan operation.

 

Yeah, maybe my cooling fans were designed to never turn on when the engine isn’t running like some cars dohere is a warning sticker on the fan assembly that says to keep your hands away from the fans because they might turn on even when the engine isn’t running though.

There’s nothing in the owners manual of value pertaining to this issue. (If it is even an issue.)

Even on very hot days I’ve never seen the temperature needle rise above the 3:30 position.

I am confused about something you said here…

“Swap the fan relays and repeat the test. If the fans operate correctly, the relay swapped out was bad and needs replacing. Since the fans run with the AC on you know they are good.”

Are you saying that since I already know that both fans run with the AC on that there’s no need to swap the relays? (AC and heater both work.)

In the fuse box that’s in the engine compartment there are three large equally sized relays in a row.
R14 = Cooling fan
R15 = Rear AC
R16 = Heater & AC

 

Since both fans run with AC on then how can I test them to make sure they kick on to cool the engine with the AC off? I have never heard the 2 cooling fans kick on (or stay on) to cool the engine AFTER the engine is turned OFF on a hot day like other cars I’ve owned.

I never have either, even in 100°+ weather. Are you having overheating problems? If not, don't worry about it. I think it's an indication that the cooling system is properly sized and designed by Toyota.

I have owned this Sienna for a little over a year and it always runs cool according to the temperature gauge.

I don't think I've ever seen the temp gauge much above the 3 o'clock position. Last winter, though, I noticed the temp gauge was sitting at 4 o'clock while driving 80mph on the interstate at 50°F ambient temps. Usually it's at or near 3 o'clock. Stopped overnight, ambient temp was 20°, and a five miles after starting out the CEL popped on. Had the code read at an auto parts store and they said P0128: COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE.

Changed the thermostat and the gauge went back to nearer the 3 o'clock position and the code never came back. My guess is that the thermostat wasn't closing completely when it should have, allowing the engine to run too cool.

 

Ok, after attaching a sticky note to the instrument panel that said “CHECK FAN!” (because I kept forgetting to check it after driving), I finally checked it yesterday after driving a while and both cooling fans are definitely working. They are very quiet.

Thanks for your input everyone.

 

Thank you for posting your results. It will help others in the future.

 

I too wondered about the operation of the cooling fans. Normally , for my van at least (06) , the temperature needle is at the 3:30 position. So one day I hooked up my scanner for live data and had the car idle for a while to see if the fans would turn on. At idle it took a long time for the coolant temperature to increase. So I sped up the process by revving the engine to 1500 rpms and at 96 degrees C the fans turned on !! I believe the thermostat is a 82C one. So my 06 comes with a tow package. I pulled a fan controller out of a Sienna from a salvage yard and the part number was different from mine. I figure the temperature schedule is different for a non towing package Sienna. I am tempted one day to install this and see what happens temperature wise.