Overheating problems after coolant flush (temp shows normal), [SOLVED] Blown Head Gasket Options

[97Corners]

Greetings.

Car: 1997 Celica GT 2.2 5sfe, 125k miles.

Problem: Overheating; The temperature gauge has never gone above the halfway mark the entire time I've own the vehicle (and does slowly climb to 45% as it warms up from a cold start, then sits there, even as the coolant gets hotter and starts to boil away).

A few weeks ago I thought the engine compartment seemed a lot hotter than it should be. The metal short ram air intake tube (in process of converting to CAI) was far too hot to touch.

Soon after I checked the coolant and noticed what appeared to be rust, so I decided to do a coolant flush (probably should've just replaced the radiator at this time). I flushed both the engine and radiator with a hose until clear liquid came out (going both directions through the engine). Ran the car for a bit without the thermostat installed. Then I installed a new thermostat: 180F with jiggle valve, and topped off the coolant (didn't bother to test the old thermostat since it was cheap and easy).

I continued to drive for about a week after that (mostly not more than 7minute trips to work and back) until one day I got home from a 30min drive, opened the hood, and noticed the overflow reservoir was boiling. After it cooled down I removed the radiator cap and noticed it was broken so I bought a new one, and installed it. During that week I do remember the hearing the fan(s) come on. Sometime shortly after this I noticed when I turned the AC on, there was a bit of a louder noise while it operated (which I only heard with the windows down and at low speeds or while stopped).

Drove to work and back a couple more times, then after another 30min drive, I got home, and there was steam coming out of my hood. The radiator (which looked like it could've been the original) had multiple cracks along the top where the coolant/steam was ejecting. So I drained the coolant, did another flush and replaced the radiator with a new one. I also removed the reservoir to properly clean all the rust and what not out of it. [I have changed the oil once before all this happened, and again recently, and never has there been any coolant or discoloration of the oil.]

I filled up the radiator (and poured some water in the overflow) and started the car with the cap off. I was only able to get about what seemed like 3 liters or so into the system. The top hose began to get very hot and then it started steaming/boiling out of the top of the radiator. The fan did not turn on. The temp gauge showed normal. My initial thought was that the new thermostat wasn't opening, since that bottom hose was still cool, and thus, the hot coolant wasn't reaching the sensor down there to turn the fan on. (I did detach the plug to the sensor and turn the ignition on and the driver side fan turned on and stayed on [is that right that only one turns on unless the AC is on?]).

I removed the thermostat and did the water boil test with a thermometer in the water and it opened at about 183F. Just for kicks I bought another one without a jiggle valve for $5 and it opened at 180F exactly. I could run water through the radiator and the engine so I knew there wasn't any blockage going on there. I have tried reinstalling both of the new thermostats and filling the system, but the same thing keeps happening: bottom hose stays cool, top hose gets hot, temp gauge normal, and steam/boiling starts. I have not found any rust since replacing the radiator so I assume that was all caused by the old radiator.

Today I tried one more time, thinking maybe there's just a big air pocket. The car was already at a slight incline facing up hill, so I then removed the thermostat (to make sure it wasn't blocking the coolant), reattached the hose and filled the system with water. Then I installed the thermostat again and started it up with the rad cap off. It did the same thing (heated to boil in the top, but the bottom hose stayed cool and temp normal), but it seemed like I was able to get more fluid in there than all previous attempts. I have not tried this process with the coolant sensor plug detached at the bottom of the radiator, but would not having the fan on really have anything to do with that bottom hose staying cool? (I'm assuming the sensor works, but the hot coolant is simply not circulating far enough to reach there through that bottom hose).

When the coolant ejects after it heats up with the cap off, it comes out in pulses every second or two, not a constant stream.

What more diagnostic tests can I do and what further information can I provide to you?

I have been searching this forum and Google for 3 days, and found many people with similar problems, but not one with all of my exact symptoms.

I should mention, about a week before this all started I did feel like I had a loss of power once it warmed up (except while traveling at freeway speeds).

Other notes, the AC has always blown cold and the heater, hot. No leaks have been found of any kind. Have never seen any smoke from the exhaust.

List of items replaced:
-Thermostat (Napa part number ATM 1542403)
-Radiator (Napa part number NR 2543)
-Radiator cap (Napa part number BK 7031728)
-Coolant (green)




*EDIT: I'm thinking it's gotta be the water pump since I confirmed no blockage and that the thermostat works fine, even though there are no unusual sounds or leaks...

This post has been edited by 97Corners: Aug 10, 2014 - 5:43 PM

[IfWeChoose]

Try burping it again. I had a similar issue with a Mark III Supra. I had a lot of growling behind the cluster and burped the system enough to rid the car of the growling, but there was still A LOT of air in the system - causing overheating problems. I had to park at a very extreme angle to get this settled (about 35%). I went sideways up this huge hill on UNCC's campus and cut it uphill at the last second, I thought I was going to slide down! Anyways, I opened the radiator cap and only turned the engine over for half a second, without letting it turn on completely and starting running. I topped off the radiator after each time that I turned the engine over. After this, I no longer had any issues. The air bubble could cause poor circulation and overheat a pocket of water.