1992 Camry V6 overheating

[gnozahs]

I've replaced the water pump, radiator caps, and the radiator but I'm still overheating. I tested the thermostat and it still works. When I drive it for over 10 minutes, it starts to overheat and climb near the H and then come back down and then goes back up again. This happens when I'm on the little streets and on the highway. It doesn't matter if I'm moving, it will still climb in temperature nearing the H. It goes to the H when I'm at a stand still. How would you check the fan? I'm thinking it might be a blown headgasket? Help.

[Nervous]

So, you have 3VZ, I assume...
First of all make sure your fan(s) kick on. I hope, 3VZ is similar to 1MZ even though the fans are hydraulic. So, if you turn on A/C - does your fans turn on?
If yes, then fans and relay are ok.
Next step is to find ECT Switch. Go to camrystuff.com and download the manual for Lexus ES300 93 - it has the same engine as yours. Locate the ECT Switch and disconnect it. Fans should turn on instantly.
If it is so - you might have a bad ECT Switch. That manual has a procedure to test it continuity in different temperature conditions, perform them before buying a new one.
Other possibility is air trapped in the system. Did you bleed the cooling system after all of those repairs? With heat set on Max? What is the temperature of air coming from the heater, btw - warm or really hot?

As to the head gasket.... Several ways to make sure it is or not so. If HG is busted coolant may turn into crap looking substance. You may see milky stuff in your oil. Your spark plugs are wet. Your compression is low. Finally, you can do pressure test to the cooling system to see if it holds the pressure.

Yeah, and to TN!

[Nervous]

You can find some info from this topic useful for your research as well:
Fans are not turning on when coolant is hot

[gnozahs]

Update:

So I decide to change out the thermostat with a new one just to know that I have a new in there but when I put everything back in, I am leaking coolant like crazy out of the metal/aluminum hose that goes into the thermostat housing. I took it back out and made sure I slid it into the thermostat housing good but it still leaks like crazy. I'm thinking I might need to get this part new or replaced? I took out this metal piping and it looks a little bent. It doesn't look straight. I think I bent it from trying to yank it out when taking out the thermostat housing. Where can I get this part?

It's the metal pipe that connects from the thermostat housing to the lower hose.

[gnozahs]

Okay so I fixed the leak. I cleaned up the pipe and sanded it up and now it doesn't leak. But the car still overheats within 45 seconds after driving it. I'm thinking BHG.

[Nervous]

Do the cooling system pressure test. You can rent a tool at AutoZone.
Another way to rule out BHG is to measure the compression in each cylinder (with all spark plugs removed).

[gnozahs]

Originally Posted by Nervous

Do the cooling system pressure test. You can rent a tool at AutoZone.
Another way to rule out BHG is to measure the compression in each cylinder (with all spark plugs removed).

Thanks. I'll try that.

The other day, I let the car idle for about 30 minutes and the temperature was normal(below half). I drove it hard around the block and it stayed normal. Once I turned on the A/C and let it idle for about 15 minutes, the temp started to climb and eventually got near the H. I can hear the fan kick in louder and everything but it still overheats.

[Nervous]

At this point I would think it is failing water pump. If impeller is broken it might not pump coolant, especially when RPMs are low. When you are driving your RPMs are higher and this might be enough to pump coolant to cool down the engine....
When the last time water pump was changed? What is the mileage on it right now?
This is how starting to fail water pump may look like:

[BamZipPow]

So the only time it overheats is when you turn the AC on?

[Nervous]

3 things to check:
1) if you put heat on HIGH - does it blow hot or just warm air? If you increase RPMs - any changes?
2) Once it starts to overheat during the idling - increase RPMs up to 3000, any changes?
3) Yeah, if you don't use A/C - does it still overheats?