How do I air bleed engine coolant 2010 w/ air bleed valve

In my 2010, the reservoir has a "B" line located up above the "F" line.

When I changed the coolant, I opened the bleed valve (I found it had a crosswise slot in it; I just found a long narrow piece of flat metal to place in the slot and turn like a handle, no need to disturb the cowl). Then I filled the reservoir to the "B" line, which is also just about the point where some coolant begins to spill out the bleed valve.

Then, following the manual, I closed the bleed valve, burped the larger hoses a few times, checked the reservoir level and topped it back up to "B", capped the reservoir, ran the engine in inspection mode until it reached thermostat opening temperature, and let it run that way for 7 minutes or more while continuing to shake and squeeze the hoses.

After I stopped the engine and let it cool down, when I checked the reservoir level, it was right at "F", just about as exactly as if I had filled it there myself. It seemed as if the engineers had almost perfectly calculated the volume of trapped air that would come out in the process.

 

I changed the engine coolant on our 2010 a few months back, left the bleed valve open (with a clear tube attached to avoid spillage). When refilling oolant started coming out a bit before I got to the full line on reservoir. I shut it, continued filling to top mark.

Then ran the engine in maintenance mode for a good half hour (per Repair Manual Guidance). Coolant level never budged to speak of, and never did get the fans to come on. Gave up. Monitored over the next few weeks, everything fine.

 

In my case, I was following the manual, so I had the reservoir cap on during the time I was running the engine up to operating temperature and burping the hoses.

During that time it just trades air for coolant in the reservoir. The reservoir starts with coolant up to B, and ends up with coolant only up to F and the remaining space filled with air that came out of the engine.

 

We have a wiki page that Elektroingenieur kindly put together with a wealth of different ways to get access to the manual.

The best manual is, well, the manual. Alternatives are ... not best.

 

My post has repair manual excerpts.

 

You did open the bleed bolt, and saw coolant come out (as you fill) before closing?

For next time: when taking off the intake manifold, you do need to take off the throttle body, but it’s coolant lines have enough play that there is no need to disconnect them. Just tie throttle body to the inverter conduits or something.

Somewhat similarly, if removing Exhaust Gas Recirculation cooler, you do need to disconnect its coolant lines, but if you drain about 2 quarts of coolant (at the rad drain), the cooler will be high and dry.

When all is reassembled, open bleed valve, attach clear tube (just to avoid spillage), and pour coolant back into reservoir. Close valve as soon as coolant starts coming out of it.

 

Can you confirm step by step that you:

1. Filled to B with bleed valve open, saw fluid come out bleed valve?
2. Closed the bleed valve?
3. Burped the hoses?
4. Made sure reservoir was still at B or topped it off again to B?
5. Capped the reservoir tightly?
6. Started the engine in maintenance mode?
7. Watched coolant temperature until it reached thermostat opening temperature, and confirmed it (by feeling hot coolant circulating in the lower radiator hose, and seeing it circulate from the small upper return hose to the reservoir)?
8. Continued running for 7 minutes or more after confirming the thermostat was open, continuing to shake and burp hoses?
9. Shut off the engine and waited for coolant temperature to return to ambient?
10. Checked the reservoir level and confirmed it had fallen from B to F or lower?
11. If it was lower, topped it back off to F?

If you did follow those steps exactly and confirm all those points, then possibly the flashing of your overheat light is for some reason other than an air pocket.

 

Any chance the coolant pump is failing?

Can you confirm that no coolant leak sealers have been used in this vehicle?

On my Gen 2 I put my front wheels up on ramps and ran the engine in maintenance mode and successfully purged all the remaining bubbles that way. On my Gen 3 I used the airlift without issue. To ensure maintenance mode brought the engine to normal temperature I ran it with the hood closed and kept the RPM up slightly, otherwise, it just wouldn’t get there.

 

Yes. I think the bleed valve pretty much did the job though. The reservoir level “might” have dropped slightly during the long idle, near nothing though.

For 2012 model year onward where Toyota nixed the bleed valve (yes!), I think you could temporarily pull off the topmost hose there, achieve the same function.

 

The volume of the reservoir between the B line and the F line is the volume of air the engineers expect to be removed from the loop during the long idle. The manual explicitly says to make sure the level is at B before capping the reservoir and beginning the long idle, topping it off first if need be, and then to make sure it is at F or below after the engine is stopped and has returned to ambient temperature (then top back up to F if it ended up below).

If the long idle hasn't dropped it by the amount from B to F, then presumably there is some air still to be worked out.

 

Having another read: you are right on all counts regarding the B line, capping the reservoir and so on. I followed @NutzAboutBolts video, filled and left cap off for the protracted run. Think I managed to get lucky though (Knock on wood...): this a couple of months back, and have not had any problems, with protracted highway drives. Will keep it in mind for the 15 year change, do it right.

 

Without necessarily saying you don't have trapped air, there's a definite possibility that the overheat light you are seeing is a result of all the sealer poured in.

 

Try flushing with a 50/50 white vinegar/water solution. That’s recommended by one stop leak seller, as capable of dissolving the gunk. If you can find some nuggets test first.