AutoElectNG:


The key to resolution appears to be concentrated in the bolded parts of your query.

Wrong repair procedure, instead of running the fans directly, he is supposed to troubleshoot why the ECU cannot get a signal that the compressor is on and turn the fan on at the highest possible speed as well as cycle the compressor on and off according to the inbuilt logic based on parameters it receives from a variety of sensors.

If care is not taken, resolving the bolded, will address the problem.

Here is the scientific explanation.

When you turn on the a/c, you increase the load. When you increase the load, you increase the heat produced. That is why the act of turning on the a/c also turns on the fans to offset the extra heat produced.

Your ECU is unable to regulate the A/C compressor if I get that you called it manual because of such non-regulation.
Your ECU is unable to regulate the fans because of the direct connection.
Your tech has deviated from design parameters without making adequate bypasses to take care of the non-stock condition.

The ECU has algorithms for running the fans at a variety of speeds to address a wide variety of heat levels, but it needs inputs from a variety of sensors such as the Engine Coolant Temperature Sensor, the fans, the compressor, etc to do that.

It no longer has access to input from the fan nor the a/c and is akin to a pilot flying with incomplete bearing determination parameters, would you love to be a passenger in such a flight?

Until you return to stock configuration or redesign the system to address the new operating parameters, this vehicle will continue to overheat.

A few questions for you.

1. Which model year of corolla?
2. Did this vehicle come with a/c factory fitted or is the a/c a retrofit?
3. Has the operation of the a/c always resulted in overheating or is this a recent happenstance?
4. Please clarify what you mean by the use of the expression "manual compressor"?
5. Is the compressor installed meant for this vehicle or a non-identical transplant?
6. Does the vehicle happen not overheat even if the a/c is on PROVIDED THAT you are in freeway traffic as opposed to stop and go traffic?

earthrealm:


U NAILED IT, but sadly he and his army of mechanics wont understand or care, all they care is install double radiator, remove therstat and all sorts of rubbish,
what you explained above is the correct resolution of his probs

safari0412:
I also experienced this,just change ur radiator to a double cell.

BumbleBee007:



OP, you should get yourself a 'BRAND NEW' (Not Tokunbor) Radiator and your problems are solved!!!

AutoElectNG:




A few questions for you.

1. Which model year of corolla? *2008/2009*
2. Did this vehicle come with a/c factory fitted or is the a/c a retrofit? Its retrofited
3. Has the operation of the a/c always resulted in overheating or is this a recent happenstance? *Yes it has for the one month I've had it*
4. Please clarify what you mean by the use of the expression "manual compressor"? *Retrofitted compressor that does not control the fan when it comes on*
5. Is the compressor installed meant for this vehicle or a non-identical transplant? *Non identical transplant*
6. Does the vehicle happen not overheat even if the a/c is on PROVIDED THAT you are in freeway traffic as opposed to stop and go traffic? *The vehicle doesn't overhear at all, if the a/c is not on. No matter the type of traffic*

FrankGiel:
Don't be too quick to change to a double cell radiator..
- how long have you had the radiator..
-when did this problem start.
-does the car overheat in the evenings/night

A whole lot of uncertainties could be the cause. It will need you delineating one from another.
I have a feeling the radiator is actually worn out regardless of whether its leaking or not and it will need replacement.. Double cell might be more appropriate. I'm assuming its an old model corolla (below 2006)

Before you change, have a competent rewire check out the electronic configurations.. Let him be certain the fan is not failing as you drive. If your fan fails, you will have this problem..

This should not be a rocket science problem..
Like i said before let a competent rewire advise you.
If you are in Lagos I have a good rewire at surulere (inside national theatre). His name is Wasiu +234 802 830 4229.

Thanks
Have a great day.

MICHEALADEX:
Get a standing fan

AutoElectNG:
Which country's corolla are we talking about here? US/Japan/South Africa? South Africa

6. Does the vehicle happen not overheat even if the a/c is on PROVIDED THAT you are in freeway traffic as opposed to stop and go traffic? *The vehicle doesn't overhear at all, if the a/c is not on. No matter the type of traffic*


I know that without A/C no overheating

I want to establish if
1. A/C is ON and
2. You are driving at speeds of 100 km or more (aka freeway traffic) for extended periods of time it still overheats?
Please run the test and revert. [b[i]]it doesn't overheat: I took it from Ebgeda to Its and back for a little over 3 hrs without a/c and it did not overheat[[/i]/b]

Finally, seems you just got the ride, and you attempted to upgrade it with A/C when this happened.

elebiola:


Please how did you resolve this issue. I am having the exact problem. Its giving me sleepless nights as it is. Removed thermostat, changed radiator and recently even replaced gasket.

Would be looking forward to your reply

ojeysky:


Did you change radiator to a new exact car spec?

elebiola:


Yes I did, I changed it today double cell radiator. Brand new. Not like the car overheats but the temperature gauge rises above the middle line while using the Ac in traffic and immediately i switch it off, it comes down.

homeboy205:
Try changing your coolant temperature sensor

elebiola:
Thanks, I would try that, please do you have an idea of price?

elebiola:


Yes I did, I changed it today double cell radiator. Brand new. Not like the car overheats but the temperature gauge rises above the middle line while using the Ac in traffic and immediately i switch it off, it comes down.