[Shaggyman]

2005 Corolla CE 1.8.
Overheated to the point of blowing off the upper radiator hose.
(Daughter is not always very attentive to things like temperature gauges)
DTC was set for the Coolant Temp Sensor- I tested it, failed it and replaced it.
Replaced thermostat, even though it seemed fine, and even though the frakking alternator has to be removed to get to it.
Water pump had been replaced less than a year ago, and it's a PIA, so ignored it.
Put it all back together, burped out the system and called it good.
Two days later girl calls and says it is overheating again.
Overflow tank was normal, and no coolant loss was evident, and no DTC.
I drove it around a bit and could not get it to misbehave at all.
Double checked the cooling fan operation and the CTS- all fine.
Next day she calls back- overheating almost to redline, and no heat.
I started it up cold and let it sit until the fan came on, and then some- no heat in the cabin.
Upper radiator hose HOT, lower hose COLD. Okay- water pump. Pulled pump, fine- no detached impeller or other discernible defect. Scratched head, removed hoses and inspected for delamination- still almost as new as when I put them on less than a year ago.
Did some checking, and the water pump literature states that it turns counterclockwise- and it does.
In looking at it, it appears the vanes are set for clockwise rotation, but so are all three of the other pumps I looked at from different manufacturers.
Removed thermostat, gutted it and reinstalled so that there would be no question of it being stuck.
Put it all back together and ran it until the fan finally came on. Upper and lower hoses both hot, and good heat inside.
WTF? Anybody?

 

[Riick]

You were obviously losing water somewhere
Four possibilities come to mind
Radiator pinhole
Freeze plugs
Hose clamp loose
Radiator Cap (unlikely)

 

[Shaggyman]

Missed the part where I said no coolant loss?
Pinhole, etc would not explain a fully topped up system not supplying flow through the heater core.
It ACTS like the water pump is not operating, although it is most assuredly doing so.

 

[sdspeed]

Have a 93' MR2 do the same thing! Went thru what you have to no avail. Ended up being a warped head, took close to 4 months of tinkering and driving before i accepted the fact that it may have a head problem since their was no visiable loss of coolant. But then again I was always tinkering with it
The head bolts had stretched.
I know you finally got the heater to work but that usually is a give away to head related issues or major air in the system.
MR2 is terrible to burp!
Goo luck.

 

[Shaggyman]

The 1.8 engines are no prize when it comes to getting the air out, either.
How hard would it have been to put in a high point bleed valve?
Come to think of it- I have a drill and a tap set...
Back up there (I live 50 miles away from my daughter) tomorrow for some more fun and games.

 

[Blackness]

What do you mean when you say you 'gutted the thermostat'? Did you just get rid of it and are operating without one?

The first thing you need to do is pressure-test your cooling system to check for leaks. If you don't have a pressure tester kit, go down to harbor freight, bring up the 20% coupon on your phone, and get you a $50 pressure tester kit... pump the system up to ~17psi and watch the gauge and check for leaks...

IF you have no leaks/pressure holds for a few minutes at 17psi, I would next highlight the fact that the upper radiator hose was hot, and the lower was cold... this typically means the radiator is clogged.. assuming the waterpump is still working correctly... typically the impellers on the waterpump fail due to using mostly water in the cooling system...

Anyway, step #1: pressure test the system... then report back and go from there... And hopefully your daughter didn't warp the head... but yes, pressure testing the system will also tell you if she did warp the head or not too....:laugh:

 

[heartdisease]

Good advice ^^^ I would also look for one of the test strips for exhaust gas in the coolant. It sounds to me like you might of had a bad thermostat or clog then perhaps didn't get all the air out? You don't suppose someone mixed antifreeze types making sludge out of your coolant? Some college boyfriend type trying to help? Just guessing...

 

[Shaggyman]

I have not found any test strips that detect combustion gases- sure would be handy, though!
Tested the OEM thermostat in a pan of water on the stove with a digital thermometer.
Cracked open at 179F and fully opened at 196F.
BUT the total lift was only about 6mm. Spec calls for 10mm minimum.
Hmmmm.
New stat from Toyota today, along with a leak test and combustion gas test.

 

[heartdisease]

https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias=aps&field-keywords=exhaust+gas+test+strip

Most Napa's around here have them. Sounds like you'll have it figured out before you could order some. Fingers crossed for good news.

 

[CorollaCharlie]

I would be weary of a warped cylinder head depending on how long she drove with the engine at red line heat. While the 1ZZ-FE might be somewhat of a work horse, no engine is impervious. However I see you mentioned that the upper hose was hot while the lower was cold. Or vice versa. At that point I would suspect a thermostat. Try flushing the radiator itself with a hose and making sure water circulates through the radiator. If it does then my immediate suspicion would be thermostat.