My vehicle experienced engine overheating problem

MAMRO

MEMBER
2007 CHEVROLET UPLANDER
3.9L
V6
2WD
AUTOMATIC
150,000 MILES

My vehicle experienced engine overheating problem due to leak on water pump. Car was driven out of coolant.
I changed radiator cap, ECT sensor, and water pump. The problem of overheating still observed at idling. Gauge pointer will exceed gauge center by more than one division before radiator/condenser fan assembly start. As a precaution in garage they removed thermostat as it is not available in local market. But still overheating is encountered at idling accompanied by the late late fan start.
Appreciate any guidance?

5 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

It sounds like you could have a clogged radiator, stuck thermostat, coolant leak or the radiator cooling fan is not working and there is an outside change you have a blown head gasket as well but to be sure lets run down these guides to help us pinpoint and fix the issue.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

and

https://youtu.be/5zpNjYmmiYY

and

https://www.2carpros.com/articles/car-is-leaking-coolant

and

https://www.2carpros.com/articles/replace-thermostat

Let us know what happens and please upload pictures or videos of the problem.
This could possibly be an air pocket that is trapped in your vehicle's cooling system that is not allowing the coolant to circulate. In order to fix this, drain the coolant and the refill from the highest point possible on the cooling system. The coolant will fill the bottom of the cooling system and fill up pushing the air out of the top is it fills. In the diagrams down below I have included the locations of the Engine Coolant Temperature[ECT] sensor and switch[Computer/Gauge] respectively, as well as a description from the vehicle manufacturer of how the cooling system on your vehicle works. Please go through these guides and get back to us with how everything turns out.

Check out the diagrams (Below). Please let us know what you find.

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Sunday, May 23rd, 2021 AT 11:31 AM

MAMRO

MEMBER
4 POSTS

Dear Alex,

Your reply and attachment are very valuable to me and highly appreciated.
Once I receive the thermostat (ordered from Amazon) I will drain, flush, and refill the coolant from the highest point in the system as per your guidance.

As per your reply I got the following interesting threshold related for the cooling fans:
Fans low speed engagement 103/108 C
Fans high speed engagement 108/111 C

I was expecting less temperatures for these settings and now after fixing water pump, thermostat, and temperature sensor I would like to know what actual temperatures are corresponding to one hash/division after gauge center, and some times little more, at which my cooling fans are starting now.

May be one division after gauge center is corresponding to only 103 C which is considered normal to start fans at, as per your valuable information!

Regards

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Sunday, May 23rd, 2021 AT 11:31 AM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello again,

The best way to find out this information is to get a reading when the fans turn on with a infrared thermometer. Point it at the upper radiator hose and take your reading there. Here is a link below explaining how to do this:

https://www.2carpros.com/articles/how-to-use-an-infrared-temperature-meter

Please get back to us with what you find out.

Thanks,
Alex
2CarPros

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Sunday, May 23rd, 2021 AT 11:31 AM

MAMRO

MEMBER
4 POSTS

Dear Alex,

Thank you again. Today I managed to get infrared thermometer and while engine at idling, I made the temperature measurement at which fans are started and dash gauge is reading one division after gauge center. I found this temperature is approx 105 C (measured at engine metal part to which upper radiator hose is connected and 97 C measured at upper hose body close to engine (see photo 1). I think the first could represent coolant temperature more accurately. Comparing these values to ones provided thankfully from your side (see attached photo 2) can we conclude no overheating is experienced at idling.

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