Car is STILL overheating, Need help! Options

[ILoveMySilly97]

Car:
1997 Toyota Celica GT

Location:
Central California(It's pretty hot nowadays since it's hitting summer)

When I started to notice the overheating problem:
My car ran with no over heating problem until AFTER I replaced both the ECT sensors because I had a P0115 CEL code. When I had the code my car would start then idle rough and then stall. So I bought an OBD2 CEL reader and I had the P0115 code. So I replaced both the ECT sensors and the CEL went away. The next day I was driving to Fresno(45 min drive). It drove ok(but I'm not sure because I didn't keep an eye on the gauge) until I started the car again about 6 hours later. At first it was at the correct temperature until about 15 min into the drive and I noticed it jumped up to 70% and back down. That was how and when I started the notice the over heating problem.

Problem:
Overheats once the car has been driven for about 30-40 min. My normal operating temperature is about 45%. When it starts to over heat. It'll jump up to about 65-70% then back down to about 50%. Then slowly to 45% again. Then like after another min it'll jump back up and repeat the process.

I noticed that when I was at a stop. The fan kicked in and the temp gauge jumped up to about 55% then slowly up to 70% then back down to 50% again.

EDIT: Just got back from testing my car and it seems to like to heat up to about 60% right until the fan kicks in. It'll drop to 45% then immediately and slowly climb back up to 60% and then stays there until the fan turns off. It'll slowly crawl back down to 45%. And it repeats itself. I'm thinking I might just have a faulty Coolant Temp Sensor, the one that goes to the ECU and not to the Dash. This was all done while the car was idling. Any ideas?

What I've done so far in order:
1st- Replaced both ECT sensors. 2nd- Replaced thermostat. 3rd- Replaced upper radiator hose. 4th- Flushed out the cooling system. 5th- Bled it out correctly. 6th- Replaced the radiator cap & bled it again. 7th- Checked for leaks, there were none. Coolant level stays the same.

EDIT #2: Ok. So here's an UPDATE. So. I let my car idle and heat up to about 70% and I just let it idle. It kept jumping when the fan turns on and off so I decided to unplug the sensor/switch so that the fan will always be on. When I did that trick. The gauge went down to about 45% and stayed there and never climbed or jump?

When it's connected. The fan will turn on for about 2-5 seconds max. I know that's too short. I think that's why I'm getting these problems. My fan is just not turning and staying on for the right amount of time. What I did was replaced the radiator and the fan switch. So I don't know why the fan isn't staying on for the right amount of time? Any ideas?

EDIT #3: Ok so I finally took it into a shop to test it out and they said my car is not overheating but the ECT unit isn't grounded properly because I had teflon tape on the threads. So I bought a new ECT sensor and installed it without the teflon tape. Results are NOTHING! The only relief is that it's not overheating at all. The gauge on the cluster is saying it's over heating but it really isn't. At least that's according to the mech I took it to. Any ideas about the ECT, PCM, and etc.???

This post has been edited by ILoveMySilly97: Jul 18, 2012 - 7:21 PM

[ILoveMySilly97]

Just got back from testing my car and it seems to like to heat up to about 60% right until the fan kicks in. It'll drop to 45% then immediately and slowly climb back up to 60% and then stays there until the fan turns off. It'll slowly crawl back down to 45%. And it repeats itself. I'm thinking I might just have a faulty Coolant Temp Sensor, the one that goes to the ECU and not to the Dash. Any ideas?

This post has been edited by ILoveMySilly97: May 27, 2012 - 2:18 AM

[xrayjm]

Just got back from testing my car and it seems to like to heat up to about 60% right until the fan kicks in. It'll drop to 45% then immediately and slowly climb back up to 60% and then stays there until the fan turns off. It'll slowly crawl back down to 45%. And it repeats itself. I'm thinking I might just have a faulty Coolant Temp Sensor, the one that goes to the ECU and not to the Dash. Any ideas?

To see if I have this right.... 60% the fans kick on, drops to 45% fans still running, climbs back to 60%, fans still running, fans then shut off, and then it drops to 45%?

if it climbs to 60% before the fans kick on then after the fans kick on it slowly drops back down to 45%((as in your first part of the description) and then repeats this process, I would suspect the ECT/water temp switch on the bottom of the radiatior as being bad.

I know on my 94 GT 2.2 the fans kick in before the gauge moves off of normal operating temp (about 45% on the gauge). My gauge doesn't move much off operating temp. I just was testing other items on my car, pulled up an 6-8% grade for about 10 miles, 3rd gear, about 5200 rpm(approx 65mph), A/C on, outside temp of 100 degress and the temp gauge didn't budge. I was also idling for about 30 min, in 108 temp, no A/C. Fans cycled on and off, temp gauge stood steady the whole time.

Here is a link for cooling fan troubleshooting for my '94. click here

I'm not sure about the second part of your description, fans shutting off at 60%, and then the temp magically cooling down. Would make more sense if your situation was fans kick on at 60%, cools to 45% and fans shut off, then repeats the cycle from there.

As a side note they must of made those '97 much quieter than my '94, cause there is NO way I can hear my fans kick on and off rolling down the road!