[Sapote]

I refilled coolant and drive a few miles the next day and it overheated again. This time, I shut it off again as soon as I could. It hit the red and I got it towed home.

Geeze, it was overheated the day before, and after adding coolant and you let it got to the red zone again and needed the tow truck? Couldn't you just driving up and down the street around the house just in case? I mean you already knew the issue, and let the gauge got to red again?

Unplugged lower radiator fan switch to trigger fan to be on full and it didn't help - still climbed past 110 Celsius

The fan won't help if the radiator doesn't have coolant flow. Get the engine to operating temp, then grasp the radiator lower hose tightly in your hand; if you don't cry in 40sec then no coolant flow through the rad. Bad bleeding job.

 

[Sapote]

Mystery Coolant Disappearing and Overheating

What mystery? When was the last time you checked the coolant in the tank?

Recently at my oil change, the guys said coolant was low but they didn't have any more.
The next day I get some drive through food and pull out hard, revving to like 6k. I look down a mile or two later and my temp gauge is in the red.

This is no mystery: was told it needed coolant; ignored and drove it hard then overheated. I shake my head.

 

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No water circulation. Sounds like a faulty pump or thermostat.

I think it was due to a bad bleeding.

 

[Sapote]

Can I drain the system and start over? Will that make the bleeding process easier?

No need to drain. Read through this bleeding to understand it, then give it a try.
Post #13 of this thread:

overheating at idle

Today I noticed my temperature gauge going past operating temperature at a drive thru. I started driving and it cooled off. I heard the fan turn on multiple times while driving. I replaced the radiator, thermostat, temperature sensor on lower radiator hose, and also bled the system multiple...

www.e46fanatics.com

 

[Sapote]

Thus, I think eliminating the circulating air before driving the car isn't worth my time -

What?

The cooling system is sort of self-bleeding - the air bubbles trapped inside circulate with the flow while the engine is running and eventually get trapped inside the expansion tank.

So before the air pockets eventually are trapped in the tank, how did you drive to places without overheating the air head, or just let it resting in the garage?

It is more important to look for leaks and to pay attention to the engine temperature.

So no bleeding air is needed, and then when the temp gauge moving toward the red zone, then shut it off and pray the GOD?

 

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I followed your instructions closely with no change. No heat and I shut the car off once I saw the temp gauge hit 110.

Did the rad lower hose got hot or cold? IF not hot to the touch then now coolant flow still.

 

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Cant quite narrow it down.

Come on, get down under the engine and look.
Bet it's either a ruptured tank or a hose connector popped out from bad workmanship.

 

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Too many assumptions here.
I fill up the cooling system as per TIS, while the front of the car is raised.
Check for obvious leaks.
Start the engine and don't bother opening the bleed screw again as some do.
Check for obvious leaks.
Drive the car a few times around the block, keeping an eye on the engine temp.
Chech for obvious leaks.
Drive the car until the engine is at operating temp, make sure the system behaves and temp doesn't go above 98-99C.
Park the car overnight.
Check for leaks on the next day, check the coolant level, top off if needed (usually less than 200 ml / 7 Oz).
Eventually check the coolant again a few weeks after, but almost never need to add more coolant.

Good for you, but there are some people had no luck and continued to have overheating and no cabin heat after doing this way.

 

[Sapote]

What may help is driving the car - acceleration/deceleration, going through bumps, revving the engine higher than at idle...

They started doing this but the gauge moving toward the red zone, then what?
My method is not much different with the TIS instruction, except I don't want to do the extra step using turkey baster to remove excess coolant out after closing the bleeder.

 

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What is the actual cause of these problems? My guess is rushing the fill entraining a lot of air, not waiting for air to come out, or sticky heater valves/blocked cores. What else could it be?

I think there is trapped air still in the head when filling up the tank until no bubbles flow out the bleeder. AFter the bleeder was closed, the trapped air could not escape during driving.
With my method, with engine running and coolant flowing through the head and flushing out the air, and with the bleeder crack-opened for air to escape until none, then close. This ENSURE no air in the head nor around the WP.

 

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I like to take the bleader screw out so I can seen when that hose is full.

With engine running or off? With engine running, you don't need to fill the tank to the top (to be removed with turkey baster later) in order for coolant to fill the upper hose as the WP pushing the coolant into the hose.

 

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I ran a leak down test today and most cylinders have a little bit of air leaking from the oil cap.

This is normal as blowby gas past the piston rings into the crankcase.

Cylinder 2 leaks a ton of air into cylinder 3.

This is the big problem: with #2 valves all closed, the only way to leak into #3 is through the head gasket, which means the head bolts were pulled off the block threads. It's time for Timesert the block head bolt holes.

It was in late September and it was resolved by replacing all the coil packs and spark plugs. (done less than 2000 miles ago as previously mentioned).

not related to the current problem.

 

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Yeah it pretty much does since the water pump failed and the car overheated. Probably warped the head and/or blew the head gasket, so it was burning coolant. One of the first things I mentioned was that I could see white smoke in the exhaust, so I think this is the root cause of all the issues I encountered

Don't give up on this engine. Remove the head, and if the block cylinders still have the honed lines on the walls, then buy a good used head on ebay -- around $250 -- and add Timesert and it should be good for another 200K miles.