Strange potential overheating issue

[03sport007]

Last night I completed my eaton swap and started to burp the cooling system. I followed these instructions.

http://reischeperformance.com/refill.html

The whole time I was doing this I never looked at the factory gauge I would just stick my head in the window and look at aeroforce gauge. It never got above 190.

So today I topped off the COT and installed the plug. This time I started the car sitting in the drivers seat(man I miss driving this car). In what seemed like a very short time the factory gauge shoot past the 20mph mark and was climbing. Howeve the aeroforce gauge was at 135. I pulled up the cylinder head temp and it also said 135. I shut the car off and will try and burp it again tomorrow. Any idea why I have a difference between my factory gauge and the areoforce?

During my swap I replaced both sensors in the COT.

[MOTOWN]

Sounds like you need to complete the burping process

[napolitano]

Sounds like you need to complete the burping process

What he said. Did you add any Water Wetter?

[fastblackmerc]

Burp the system.

[Marauder Rick]

I had the same problem. BTW, the gauges are working fine. IIRC one of the two plugs where your COT goes into the head is a pressure sensor, not a temp sensor. If the pressure is changed (it hits an air pocket) it will make your temp (in the car) fly up, but the coolant temp isnt really raising. I found this out by noticing that everytime i overheated (which was everytime i did anything) as soon as i popped the hood and safely released the pressure from the res, my temp would go back to normal....until i started the car again. Follow these steps:
*Remove COT cap
*Start car and let run
*Monitor the open COT cap (it should start producing bubbles)
*As the bubbles lower the coolant level in the plug, keep filling it back up
*When the bubbles stop coming..DONE (you should probably watch it for a few more minutes though)
*Replace COT cap

[03sport007]

I had the same problem. BTW, the gauges are working fine. IIRC one of the two plugs where your COT goes into the head is a pressure sensor, not a temp sensor. If the pressure is changed (it hits an air pocket) it will make your temp (in the car) fly up, but the coolant temp isnt really raising. I found this out by noticing that everytime i overheated (which was everytime i did anything) as soon as i popped the hood and safely released the pressure from the res, my temp would go back to normal....until i started the car again. Follow these steps:
*Remove COT cap
*Start car and let run
*Monitor the open COT cap (it should start producing bubbles)
*As the bubbles lower the coolant level in the plug, keep filling it back up
*When the bubbles stop coming..DONE (you should probably watch it for a few more minutes though)
*Replace COT cap


Thanks. Makes me feel a little better. I thought the areoforce pulled the temp from the same sensors as the gauge.

How's your car running? If I remember correctly you have the highest miles eaton swap.

[1stMerc]

You can speed up the burping by squeezing the lower and upper hose while the water in the cot is still low. Watch for bubbles in the over flow bottle. When they deminish you can add more water at the cot.

[Marauder Rick]

Thanks. Makes me feel a little better. I thought the areoforce pulled the temp from the same sensors as the gauge.

How's your car running? If I remember correctly you have the highest miles eaton swap.
Running great. I dont know if im the highest milage swap, but im probably up there. Got charged around 130k and recently turned 156k. Btw, i got charged May 1st so thats 26k in 18mos. It is my DD and i do drive a lot.:D

[justbob]

I had the same problem. BTW, the gauges are working fine. IIRC one of the two plugs where your COT goes into the head is a pressure sensor, not a temp sensor. If the pressure is changed (it hits an air pocket) it will make your temp (in the car) fly up, but the coolant temp isnt really raising. I found this out by noticing that everytime i overheated (which was everytime i did anything) as soon as i popped the hood and safely released the pressure from the res, my temp would go back to normal....until i started the car again. Follow these steps:
*Remove COT cap
*Start car and let run
*Monitor the open COT cap (it should start producing bubbles)
*As the bubbles lower the coolant level in the plug, keep filling it back up
*When the bubbles stop coming..DONE (you should probably watch it for a few more minutes though)
*Replace COT cap

+1 either your sensors are in the wrong ports, or if you replaced one/both, they are wrong. Swap the sensors or the wires.

This post is rated E for everyone.

[03sport007]

+1 either your sensors are in the wrong ports, or if you replaced one/both, they are wrong. Swap the sensors or the wires.

This post is rated E for everyone.

That's what thought but they can only go one way. The pigtails are not intherchangable?

[RF Overlord]

IIRC one of the two plugs where your COT goes into the head is a pressure sensor, not a temp sensor. I've never heard of a coolant pressure sensor on any car. The factory wiring manual only shows one ECT sensor so I'm not sure what the other one does. It makes no reference to a pressure sensor.
I thought the areoforce pulled the temp from the same sensors as the gaugeIt does. The ECT sensor also supplies signal to the PCM.

[justbob]

One is for the gauge, the other is for the computer. Did you replace any? Autozone is notorious for selling the same for both applications.

[Marauder Rick]

Well hey...that was the point of the "IIRC." I apologize if i misinformed or misguided you. All i know is my experience. When the pressure is released from an "overheating" system with air in the lines the temp reading goes back down. There's no way that the actual temperature is dropping that fast. Maybe the air pocket enters the block and it heats up and releasing the pressure pushes fluid into the block and the cooling occurs. IDK. I just know what happened.

[03sport007]

I burped the system 2 other times and never had any issues and I don't think I have a real issue now. I think is a indication problem.

During my swap I replace both sensors in the COT. The one on the passenger side I got from Ford and the one on the drivers side I got from NAPA. The one from NAPA has a green exterior and the original one had a grey exterior. Does that matter?

I started the car to try and burp it again and in a very short time the factory guage starting climbing so fast I could see it rise. The temp for coolant and cyclinder head on the aeroforce never with above 160. Didn't have the balls to let the factory guage get past about 3/4 so I shut the car off. I unplugged the COT sensor on the drivers side and the factory guage dropped to full cold. I unplugged the COT sensor on the passenger side and the coolant temp on the areoforce went -40. What's strange is the cyclinder head temp remained accurate. Where is that sensor located?

Anyway I still have my original driver side sensor which appears to be the problem and will install that tomorrow and report. I really hope I can swap them without removing the COT.

[justbob]

I think you are on the right path friend. My first step would be to swap that napa one out. Way too good of a chance that the OHMs are nowhere even close to what they should be.

But before you do, maybe spend some google time on how to test the OHMs and find the parameters that it should be in. I love putting facts on bad parts. I also love taking bad parts back and reading them the riot act and walking out with free coolant..

This post is rated E for everyone.

[RF Overlord]

spend some google time on how to test the OHMs and find the parameters that it should be in. According to the factory wiring manual, the resistance range for the ECT sensor is approx 1.2k ohms when at high temp and approx 160k ohms at low temp. Unfortunately that's as specific as it gets...

[03sport007]

I replaced the one I got from NAPA with my original and all is well. Thanks for the input and Help.

I'd still like to know where the cylinder head temp sensor is?

[03sport007]

..............

[Marauder Rick]

http://a1.sphotos.ak.fbcdn.net/hphotos-ak-ash4/392296_206710016076171_1000021 15213202_465199_405704975_n.jp g

[Marauder Rick]

^^^^Hope this helps^^^^

[03sport007]

Thanks:beer:

[mercuryed]

the two sensor on the COT are both the temp gauge sensor on the driver side is for the dash gauge and the CHT is the one on the passenger side that the ECU reads from. i ran in to the same problem 6 mouth ago that the dash gauge would read that i was overheating but the aeroforce guage would read the temp at normal so after replacing it with 1 from the dealer she was reading correctly inline with my aero gauges but when they told me how much to CHT sensor would cost my jaw drop.179.00 from ford and when i asked was it on the block they said NO on the 2 valve 4.6 motors the CHT is on the block under the intake but on our motors 4 valve 4.6 its on the right side of the COT and the pigtail plug slots are differnet between the two so you wouldnt make a mistake about witch 1 you had in on that side.

[03sport007]

the two sensor on the COT are both the temp gauge sensor on the driver side is for the dash gauge and the CHT is the one on the passenger side that the ECU reads from. i ran in to the same problem 6 mouth ago that the dash gauge would read that i was overheating but the aeroforce guage would read the temp at normal so after replacing it with 1 from the dealer she was reading correctly inline with my aero gauges but when they told me how much to CHT sensor would cost my jaw drop.179.00 from ford and when i asked was it on the block they said NO on the 2 valve 4.6 motors the CHT is on the block under the intake but on our motors 4 valve 4.6 its on the right side of the COT and the pigtail plug slots are differnet between the two so you wouldnt make a mistake about witch 1 you had in on that side.


Wow!!! I paid 14.99 for the one that didn't work from NAPA and 18.99 for the one from Ford. 179 that's crazy!!!!!

[RF Overlord]

So the dealer tried to tell you the cylinder HEAD temp sensor was in the COOLANT crossover tube, then tried to charge you $179?

Find another dealer. :shake: