[93celicaconv]

No, I haven't! I can't believe I didn't think of this. I will check that. and if that isn't the issue, is there anything else I could check?

I would also check your heater when the engine begins to overheat. With the heater temp set as high as it goes, and the heater fan on high, do you get a lot of heat out of the heater, or none at all?

No heat at all means either no coolant circulation or a blocked heater core.

Plenty of heat means good coolant circulation (at least through the engine) and the heater core is not plugged (meaning a stuck closed thermostat or the radiator cooling fans are not operating).

If the heater works well, but the coolant temp starts to elevate above normal on the radiator, I would check (by hand or infrared thermometer) the temp. of both the upper & lower radiator hoses. Are both hot? If so, good coolant flow. If not, for some reason, restricted coolant flow through the radiator.

If both hoses are hot and the temperature gauge is going up above the normal operating temperature, the radiator fans should be on. Are they? If not, your radiator coolant temperature switch may be inoperative. I believe if you disconnect the wiring harness at the switch, the fans should run. Do they? If so, the radiator temperature switch is bad. If the fans do not operate, you should check your fuses. You may have a bad fan or both fans may be bad, which may or may not blow your fuses.

 

[93celicaconv]

If we look at a single cause for all your symptoms, I would say you have little coolant flow throughout the system (not enough to get heat from the heater core, not enough to get hot coolant cooled in the radiator, not enough to flow coolant through the engine. You could have multiple issues accounting for all your symptoms, but I wouldn't tend to want to problem solve that way.

The fact that you have a new water pump installed is concerning. Assuming it was installed correctly (toothed part of the timing belt in contact with the water pump pulley), it would be hard to imagine the water pump is at fault. Did you install the water pump? Did you spin the water pump pulley prior to installing it and made sure the impeller was solidly attached to the shaft?

Equally hard to imagine is that there is a blockage so great that it is clogging flow through the entire system.

Regarding the air bubble theory, the only way an air bubble can block flow through any part of the system is if it resides within the water pump itself.

If you changed your water pump, why did you change it? Was it overheating prior to changing the water pump? Did you see anything wrong with the old water pump? How did you burp (remove air) from the system when you were finsihing the work and adding coolant into the system?

 

[93celicaconv]

Update: Yesterday we did some diagnosis and figured that it was a non-functional water pump. we pulled the top radiator hose, and there was zero flow through either end. so we went out and bought a new water pump, and once we got down to it, we realized that it was really an engine out job. So, since we both go to tech school in the auto tech class, we decided we are just going to trailer it out there and do it right. before we do that though, I'm going to try to force water through the cooling system with a garden hose, just in case it is just an air bubble somewhere causing this. Am I missing anything?

It's too late now, given you've taken things apart to the point you have to trailer the car now to get to the water pump (which surprises me regarding access, on my 5th Gen (1993) Celica GT, I was able to put a new water pump in w/o removing the engine). Not sure why yours would be different.

Anyway, if the engine was cold when you ran your test with the radiator hose off, there shouldn't have been any flow. Your themostat was closed, which prevents flow through the radiator. I would have removed one of the heater hoses to check for flow. Regardless of the engine coolant temp., coolant flow through a radiator hose (provided the control valve is open) is always constant. If you had no flow there, I don't know what else it could be than your water pump, as I really doubt that the cooling chambers are so plugged that a working water pump couldn't push coolant through it.

 

[93celicaconv]

It's all back together. I had to get it back out on the street and out of daddy garage. the only part still off is the timing belt cover, which, given the condition, wasn't doing much. looks like a ball bearing shot right through it. the only reason it needs to be trailered is because our school is a 50 minute drive, which doesn't work well when you have an overheating problem.

The GT has a smaller motor. that's why it's different. the GT uses the 3S-GTE, while the GTS uses the 5S-FE. and we let the engine overheat with the tube off. the only flow we got was bubbles of steam when it overheated.

And you're thinking exactly what I'm thinking. while we've got it in the shop though, I am going to check to make sure water is flowing through the engine. if it's not, I found a 92 Camry that's been rear-ended beyond repair on craigslist for $250 that can donate an engine.

For reference, for the 1993 model year Celica:

• ST: 4A-FE 1.6L N/A Engine
• GT: 5S-FE 2.2L N/A Engine
• GTS: 5S-FE 2.2L N/A Engine
• All-Trac: 3S-GTE 2.0L Turbo Engine

The 5S-FE & 3S-GTE engine are identical in physical size, only the bore is different to cause the displacement difference. So your GTS and my GT have exactly the same engine. You shouldn't feel you have to remove the engine to get the water pump out.

Also, when you tested for coolant flow, if you did your test with the engine hot and with only to upper radiator hose off, you should have seen flow (until the radiator would have been pumped out empty). Sounds like you did not. That could be a sign of a stuck-closed thermostat. But even with a stuck-closed thermostat, if the water pump was good, you should have had coolant circulation in the engine, resulting in coolant circulation in the heater core, so you should have had heat. Do you know if your heater core coolant valve is operating properly, and not disconnected or broken in the closed position?

Bubbles of steam coming out? Are you using a 50:50 mix of anti-freeze and distilled water? Hopefully not just pure water (pure water boils at a 212 deg F, which the cylinder walls are above, so the walls won't have any liquid against them to take the heat away, which is very problematic. A typical 50:50 mix coolant boils at a much higher temp, and usually will not boil at the cylinder wall surface, so heat dissipation is good. If it did boil, it should condense back out to liquid before it reaches your radiator. So all this sounds "unusual".

 

[93celicaconv]

It may have had a little water in it still, because when I was driving home it ran out completely, and I limped to a grocery store, and had to use distilled water.

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I read through all your previous posts. This is the first time there was any mention of loosing coolant. This was before you started taking things apart (ran out when driving home). With all the work to repair a leak, you still have one? What & where is the leak?

If you drove it with no coolant, you probably will have a greater issue than trying to fix an overheating problem now.

Any idea how much stop leak was dumped inside this car? And do you know what kind of stop leak was used? I took an engine apart once where the owner said they used some stop leak - it was amazing the amount of sediments in the cooling chambers in the block (preventing proper cooling), and the radiator and heater cores were all clogged. One would have to use quite a bit, but some people are looking for quick fixes.

 

[93celicaconv]

It was leaking in the form of steam. And when it ran out (stopped steaming) I stopped on the side of the road to let it cool enough to get to the grocery store of which I spoke.

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I don't think so.

In a closed water system (assume you did not have any antifreeze in it), if your cylinder walls got so hot as to boil water at the contact surface between the water and the outside cylinder walls, that steam would condense back to a liquid as soon as it got to an area in the closed water (coolant) system below the boiling point temperature. Water will boil at 212 deg F at sea level. In your car, you likely have a 0.9 bar radiator cap (or about 13 psig), and the boiling point of water increases about 3 deg F for every 1 psig it is above atmospheric pressure. So at 13 psig, add another 40 deg to the boiling point, or about 252 deg F. Certainly somewhere in your cooling system, even assuming you have no coolant flow, the coolant will be less that 252 deg F in a 13 psig pressurized system, and that steam will condense back into liquid water (i.e.; it is unlikely for the coolant to boil away).

But, the original owner said there likely is a block problem. The bubbles you saw likely were was not boiling hot water steaming away, but rather combustion gases getting into the cooling system. Your coolant could very well be going the opposite direction (into your combusion chambers) and leaving via the exhaust.

If you cooling system is still all together, before I would change your water pump, I would do a pressure hold check on your cooling system. Do it cold and again after the engine has reached normal operating temperature. If the cooling system does not maintain a set pressure, there is a leak in the cooling system, and it could very well be coming from a cracked block or a cracked head.

You should also check your coolant that still remains for exhaust gas. There are test strips available for making this test. If this test comes up positive, you know you have an exhaust leak into the cooling system, which is sufficient evidence of a major problem.

I would do at least the exhaust gas test of the coolant (of course, you need enough coolant to do the test, and you need to have run the engine long enough to create the potential for the exhaust gas to appear in the coolant), likely the coolant pressure check, all before messing with putting a new water pump on the engine. Best to know this first.

Good luck with your analysis & repairs.

 

[93celicaconv]

The steam was coming out of the overflow tank. When I was driving home, I am reasonably certain that radiator cap was completely shot. It has a new one now, and I have yet to see any actual steam coming out with it. And its a 0.9bar cap. So when I get it to the shop Monday I'll pressure test, then if it passes, I'll put in the new water pump. If it fails, I'll talk to the guy with the Camry.

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I would also suggest you use something like this to test for combusion gas getting into your cooling system - if you can.

The pressure test needs to be done with a warm up system (because cracks can close up pretty well when cold, then open up when hot.

Let this forum know the results of your testing. It will be educational for all of us here.

 

[93celicaconv]

Ok. it's been a while. I apologize for not updating sooner. we just got everything back together today, and turned it over, only to find that there are 2 notches in the cam pulley alignment system, and we did the wrong one, apparently. thank god it's a free rolling engine! we now just need to line everything up right. oh, and the suspected issue at this point is in fact the water pump. we (obviously) have not been able to test with the new pump, but we'll see. why is the water pump suspected to be the issue? well...

Tomorrow I will try to get her running, so I can tell you she's fixed.

I'm glad you found a reason for no coolant flow. But, your very first post said the car had a new water pump. Your picture is not that of a new water pump. So what's up with the new water pump from the 1st post?

 

[93celicaconv]

Ok, it was a craigslist car. They said it was new.

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You might want to take your removed water pump back to the prior owner and ask him if he still has the receipt for that new water pump so you can exchange it for a warranty replacement. I have a distaste for sellers that falsely advertise what they sell and they never receive any feedback, so they keep doing it. But that is the type of society we are, I guess.

 

[93celicaconv]

Once you get her back on the road, you will really enjoy it. Excellent car, fun to drive. It's glad to have you as its new owner.