Overheating - No Codes - SOLVED - THANK YOU!!

Yes and so after you run it for a while and you do your business let it cool off when you get home and then crack the cap again set it on something the air cleaner and look at the level in the filler neck again You can't see any coolant does it take another 24 oz to bring it up to the top and when you get it to the top let it sit there for about 3 minutes seems like it's forever and that it doesn't drop then recap so you've got 24 oz it's going somewhere or not so you don't really need a flush You need to have a good overall look at all the hoses and connections and make sure nothing is seeping If it is usually you'll see a pinkish whitish powdery looking dry stain where that's occurring or where that water is splashing if it's squirting I doubt you really need any serious work on the car you just need to find out where the water is going if it is I have the same problem in an '09 and for the life of me I can't find the coolant leak and it's not going into the cylinders but every few days I uncap the radiator and I can add about 24 oz of water at least 16 anyway very slowly then cap it drive for another four or five days of pretty normal driving and when I check it again at the 5th of the 6th day the same thing is going on If I'm driving down the highway about 2 hours or so and my red triangle will start flashing at weird times I stop at Sheetz let everything cool off a few minutes and I notice my jug is way down so I fill it and then I crack the cap try and get the pressure out but not much coolant coming out check that part of the system and fill it and keep getting it

 

Yes, you need coolant under that radiator cap for it to transfer coolant between the bottle and radiator. On your car, if you ever find the engine coolant bottle really low or empty - you will always need to check under that radiator cap (only when cold and safe).
On newer cars, the coolant flows through the bottles and eliminates that extra check..

 

Coolant does not get “used up”. If it went down it went somewhere. Guaranteed. Your engine is at risk so find the solution.

Also you may have problems getting the required 50/50 blend of Toyota coolant in the system now that you have added a half gallon of water because not all of it comes out when draining.

 

If your not getting the intermittent cold early morning misfires; I would assume that it wasn't properly "burped", a year ago - when the radiator was replaced.
If the mechanic does a 'real' coolant system flush (using a pressurized machine) you won't have to worry about proper coolant mixtures. If he doing just a drain & fill, he only going to get 75%-80% of it out, diluting down your 50/50 premix even further. This is only an issue if you live in snow country. You can validate your coolant mixture with a $2-$5 dollar tester from Walmart. Don't test from the bottle, pull coolant from under the radiator cap for a more accurate measurement.
Prestone Tester Coolant - Walmart.com

 

Normally you lose coolant due to a leak or a loss incurred by an overheat pressure relief event.

The engine coolant spec is about 9 qts. Typically you can drain 5-6 qts if you do it by the book or less if just draining the radiator. As much as half of the water you put in remains, probably a quart.

Toyota does sell a concentrated coolant which is used with distilled water. If you estimated a quart of water was left in after a drain, you could add a quart of concentrate and then add a mix of the concentrate and distilled water for the rest.

Many shops don’t worry about it or don’t care for expediency.

From owners manual:


Remember the coolant heat storage system is isolated unless it is controlled open by a scanner.