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Discussion Starter · #1 · (Edited)
2012 AWD having some cooling issues. Started when I was towing jetskis but now all the time. No codes present.

I have replaced all relays, cooling fans, radiator and cap, thermostat, water pump, both hoses, engine temp sensor, added large external trans cooler, and checked/added refrigerant. (HD Radiator and trans cooler were to make towing better indirectly related.)

OBD reader and it shows the computer is not commanding any fan until it hits 220 degrees and that is only low it won't command high.

Started about 6 months ago.

Strange thing maybe not related but on OBD shows ambient temp stuck at 75.2 degrees but dash display shows the actual accurate outside temp

Any ideas?
 

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Most of my vehicles if the AC is off turn fans on at 220.

I did receipt my Fiero with a new chip to run a 160 thermostat and a lower fan switch at 200.

Are you running the AC as the fans should be on automatically.
 

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Discussion Starter · #3 ·
Yes even with AC on they wouldn't kick on. I did replace the coolant sensor again, the first was aftermarket brand so I used an acdelco on one and the fans did kick on low now with ac on. Need to hook up the jetskis again and take for a drive and test temps. I did verify that fans will come on fulle when I unplug the coolant sensor, the are capable of it they just aren't getting the command from the ecm.

Prob with them kicking on at 220 now is that it's already on way to overheating and just started doing it never had that problem last year it would never budge off the 210 marker (although I know the gauge reads 210 anytime between 170-215).
 

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Sensors are the most common issue. With AC off I would seldom see fans come on till 220 and with AC on they come on right away. They have to have the air for the condenser or your AC will blow off the Freon with pressure build up and then no AC.
 

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The cooling fans also receive commands from the A/C pressure sensor(s).
 

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Discussion Starter · #6 ·
That is the exact part I ordered and should be here Friday is a new AC pressure sensor. I read another post with similar symtoms fixed by that so figured for $30 it's worth a shot
 

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Discussion Starter · #7 ·
Towing and following occurs:

Fan runs on low with AC engaged
Won't kick up to high until 225-230.

Towing freeway speeds it is at about 225 two marks above 210. Also won't run on high at highway speeds really anything above 50 mpg. That is prob normal but strange that it won't go to high when heating up.

I can see it on scanner that it's not commanding high until already starting to overheat.

Hope ac sensor fixes the issues it has to be a sensor that is preventing high from being commanded by computer.
 

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Discussion Starter · #8 ·
Replaced thermostat again and the ac pressure sensor and now it won't turn on fan to high until 230 degrees. It is just running on low with ac on without regard to temps. On reader can see that the computer is not commanding high. So frustrating because it used to get one high all the time.

I did run some checks for a blown head gasket and found no sign of having a bad one.

I am bleeding system again to see if I get anymore air from cooling system.
 

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Replaced thermostat again and the ac pressure sensor and now it won't turn on fan to high until 230 degrees. It is just running on low with ac on without regard to temps. On reader can see that the computer is not commanding high. So frustrating because it used to get one high all the time.

I did run some checks for a blown head gasket and found no sign of having a bad one.

I am bleeding system again to see if I get anymore air from cooling system.
Did you check and/or fill the coolant on a cold system at the radiator cap? If you can, back up or jack up the front about 15 or 20 degrees on a cold start and quickly shut off. Then check if the coolant is up to the top at the radiator cap.

Other than that, there may be another sensor that is not not functioning properly? At this point, it may be best to have a shop with good techs and a reliable reputation to look at it.
 

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You need a bi-directional scan tool that will allow you send the command to turn on the fans to help troubleshoot this issue. Time to break out the multimeter and start checking for bad grounds or corroded connections.
 

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Agree with that. With today's vehicles a capable scan tool that just doesn't read codes or reset a CEL is something anyone trying to do DIY troubleshooting should have.

Given the age of the Acadia, corroded or damaged grounds are another best thing to investigate. Another thought, aren't there two A/C pressure sensors or maybe it was two coolant temperature sensors to check out?
 

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Discussion Starter · #12 ·
Only been able to locate one ac sensor.

Towed for 3 hours to Flaming Gorge up extremely steep grades and only pulled over once when it hit 230. Again the fans rarely go to high. Once back home I am going to go through the grounds in the relay circuit and retest them all again.

Running usually around 212-219 with just low cooling fans mostly. Heats up the most in slow city traffic and at freeway speed.
 

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Discussion Starter · #13 ·
Reached end of my rope. I used block check and did not indicate there was any exhaust in the fluid, it stayed blue in color.

Then used some Blue Devil to flush cooling system for about 3 hours then flushed and filled again and bleed system. It's now heating up worse than ever now. Running at 225 with no load cruising at 50 mph. Fans seem to be coming on as it should.

I have replaced everything and no improvement. I have another water pump (acdelco) coming that I will try but the Gates pump in it is only 6 months old so doubt it's bad, except for a few things 1-will cool down some when rev to 2k, and 2-when I was flushing it took a long time to get hot air to blow in the vents (thermostat was removed) even though engine was showing 200 degrees. It's possible that it has bad flow and just not moving the fluid very well.

I thought it was fixed because while the thermostat was out it was running 190-202 and never got any hotter for 3 hours.

So frustrated!
 

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Discussion Starter · #14 ·
Gates pump was leaking from weep hole but no improvement in temps with acdelco.

Compression is 170-178 on all cylinders and leakdown test showed a max of 4% loss across all cylinders so no compression issues.

I am replacing the condensor because I noticed it has about 50% bent fins and 80% between fins are filled with small rocks. This car came from casper Wyoming where they used lots of sand in winter so I am hoping that this has been airflow issue.
 

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I am replacing the condensor because I noticed it has about 50% bent fins and 80% between fins are filled with small rocks. This car came from casper Wyoming where they used lots of sand in winter so I am hoping that this has been airflow issue.
That could be key to resolving the problem. The condenser covers nearly the entire front of the radiator.
 

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Discussion Starter · #16 ·
I believe I have solved it. After all those changes including new radiator, water pump, ac sensor, fans, thermostat, condensor (which is nice the ac has never been colder) it was still heating up after driving for about 4-5 miles.

So I checked the trans fluid as I had flushed it last fall. Well I must not have let it fully warm up when I refilled it then because I checked again today and had to pull out nearly 2 qts of fluid to get to midpoint on stick. I have only taken it out once for about 20 miles of towing 1500 lb trailer in 90 degree weather in a hilly area and the trans fluid was only 185-190 and the coolant stayed 210-217.

I feel stupid that I forgot to recheck but relieved to have it solved!
 

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Discussion Starter · #17 ·
Not quite solved. It runs cooler and trans temp is usually 180-190 now so that definitely helps, but still occasionally while running empty and towing I get some creep in temps.

It will run around 215 most of the time but then will sometimes creep up to as high as 230, but usually tops around 226. I did tow a 3000 lb trailer and 6 passengers and it ran around 230 most of the way peaking at 240.

I don't remember ever seeing my dash gauge move from 210 until the start of this summer. Since the dash gauge shows 210 anywhere between from 180-220 it is now moving into that realm many times during each drive.

It also cools down somewhat if I drop a gear and increase the rpms. Even while stopped if I rev it to 1500-2000 the temp will rapidly drop back to 210-215.

I dont feel like this is normal but maybe I am just over sensitive to it now?
 

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Could be clogged catalytic converters? Just a thought, since you already changed all major cooling components and you mention temp goes down when you rev... pressure and heat is forced out the clogged exhaust (catalytic converters)when you step on the gas.
 
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