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      08-12-2020, 03:18 PM   #1
0-60Motorsports
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Hey guys,

I have been having an issue over the last two years gradually. The water temp starts going past half way mark with the AC on. I have had the car since 2006 and never had this issue. The car has approx 48,000 miles. Temps here are around 115-125f with high humidity. Again never had this issue before. As soon as I turn the ac off the water temps
Drop to below half or half in a minute. I have changed or checked the following things:

New water pump
New thermostat
New condenser
Radiator is good (checked by swapping with a good rad from another car)
Expansion valve for ac changed
Drier changed
Oil cooler is good
Everything is clean too and has been cleaned again.
New ignition coils and spark plugs
Oil is new
Coolant flush has been performed many many times using vacuum method and old Skool with nose up and heating on.
No coolant loss
Car makes great power.

Any other suggestions because the only things I haven't changed are the compressor and evaporator but the ac works perfect and blows cold air no problems.

Any advice would be appreciated because I am really frustrated and in just want my car to be back to normal.
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      09-01-2020, 11:57 AM   #2
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Does the car overheat if the AC is on and you're driving? Or just standing still.
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      09-04-2020, 04:16 AM   #3
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Quote:
Originally Posted by Eddien123 View Post
Does the car overheat if the AC is on and you're driving? Or just standing still.
Standing still it overheats and then when driving it'll start at 3/4 water temp but then start dropping slowly.

So the problem might be solved finally. I'll report back once the parts arrive.
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      09-21-2020, 02:24 AM   #4
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Quote:
Originally Posted by 0-60Motorsports View Post
Quote:
Originally Posted by Eddien123 View Post
Does the car overheat if the AC is on and you're driving? Or just standing still.
Standing still it overheats and then when driving it'll start at 3/4 water temp but then start dropping slowly.

So the problem might be solved finally. I'll report back once the parts arrive.
Is the aux fan turning on with your A/C? Check the fan or fan resistor....just a thought.
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      09-21-2020, 05:40 AM   #5
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Quote:
Originally Posted by Kewl X5 View Post
Quote:
Originally Posted by 0-60Motorsports View Post
Quote:
Originally Posted by Eddien123 View Post
Does the car overheat if the AC is on and you're driving? Or just standing still.
Standing still it overheats and then when driving it'll start at 3/4 water temp but then start dropping slowly.

So the problem might be solved finally. I'll report back once the parts arrive.
Is the aux fan turning on with your A/C? Check the fan or fan resistor....just a thought.
Yes it is. I replaced it with a brand new one. Result was the same.
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      03-02-2021, 04:32 AM   #6
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Did you ever find the answer to this problem?
My E46 overheats with the AC on too, but goes back to normal once I turn off the AC.
Iv changed the Aux fan, fan clutch and fan controller.
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      03-02-2021, 04:33 AM   #7
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Quote:
Originally Posted by k1k1 View Post
Did you ever find the answer to this problem?
My E46 overheats with the AC on too, but goes back to normal once I turn off the AC.
Iv changed the Aux fan, fan clutch and fan controller.
It was the alternator for me. Once changed everything was fine but I can still not give you a 100% thumbs up as I need to test it in the heat. That'll be May onwards here in Bahrain
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      03-23-2021, 10:42 PM   #8
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What does "overheat" mean? Your car may not have done that in the past, but a little past middle is normal especially as the car ages. Do you know what the actual temp you're reaching is?

I would also try doing distilled water and Water Wetter. A lot of people including me have have success seeing lower temps.
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      03-28-2021, 05:12 PM   #9
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Quote:
Originally Posted by Andrew View Post
What does "overheat" mean? Your car may not have done that in the past, but a little past middle is normal especially as the car ages. Do you know what the actual temp you're reaching is?

I would also try doing distilled water and Water Wetter. A lot of people including me have have success seeing lower temps.
It reached a displayed temp on the OBD to about 95c and rising buy would drop when driving. Everything is brand new. I'll try the distilled water and water wetter in a month or two as the temps here start rising.
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      08-05-2021, 11:13 PM   #10
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Quote:
Originally Posted by 0-60Motorsports View Post
It reached a displayed temp on the OBD to about 95c and rising buy would drop when driving. Everything is brand new. I'll try the distilled water and water wetter in a month or two as the temps here start rising.
Any update on this? I am having the same issue.
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      08-06-2021, 05:19 AM   #11
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Quote:
Originally Posted by dsphil View Post
Quote:
Originally Posted by 0-60Motorsports View Post
It reached a displayed temp on the OBD to about 95c and rising buy would drop when driving. Everything is brand new. I'll try the distilled water and water wetter in a month or two as the temps here start rising.
Any update on this? I am having the same issue.
No updates. The issue is the cars not making enough amperage to power the aux fan to full speed so that's causing the overheating for me. No voltage drops or battery drain so it's very hard to diagnose. Car is parked up at the shop and they work on it when they get a new idea. Every earth connection on the car has been checked and verified
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      08-31-2023, 05:30 PM   #12
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Problem solved, it was the alternator. Changed to 140amp X5 alternator and all good even in 125f temps with high humidity.
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