Overheating while running A/C

[eacmen]

It just shows the coolant temp. One temp, not inlet and outlet.

If using a scan tool or INPA you should ve able to see both sensors.

Right now its 80F in the garage, both sensors seem to agree.




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[0-60motorsports]

My symptoms are the same as yours, only when the AC is on and I'm driving on the freeway at sustained 3k or greater RPM and Pheonix AZ heat is over 4k. I've replaced the radiator with a CSF one and the oil cooler with a CSF, run both fans, just the aux fan, just a mishimoto electric fan and nothing changes. The temps are not congruent, cluster says it's over heating, cluster test shows a higher readout than the OBD data, laser IR temp gun shows nothing in the coolant system is overheating.

This guy on bimmerforums seems to have similar issues that I'm experiencing, and it kinda sounds like your issue too. In post #16 he mentions that replacing one or the other sensor made his INPA reader show some odd readings, but when both werer replaced, the car finally showed the correct temp.

https://www.bimmerforums.com/forum/s...6#post30503676



My water pump and t-stat/hoses/radiator were all replaced a little over 40k ago. Before I throw $1k in parts at the problem, I'm going to replace both sensors and re-bleed the coolant system. Also, I bleed the CSF radiator "incorrectly" according to bimmerworld (those guys are awesome), I'll try bleeding the CSF radiator per their instructions

http://news.bimmerworld.com/csf-trip...airing-it-out/

I just replaced the aux fan sensor in the lower coolant hose and the other one is on the way from fcp. Will report back once it get here in a week. Thank you for the info and I’ll do the inpa test.

[0-60motorsports]

Well guys, SSDD is all I have to say.

The only thing not changed is the radiator that has 40,000 km on it, it looks brand new and wasn’t even dirty but I cleaned it any way. I am at a loss. I don’t know what to do. I have changed every single cooling component on the car and it still over heats with AC on and under load. Car has 70,000 km on it.

[eacmen]

Well guys, SSDD is all I have to say.

The only thing not changed is the radiator that has 40,000 km on it, it looks brand new and wasn’t even dirty but I cleaned it any way. I am at a loss. I don’t know what to do. I have changed every single cooling component on the car and it still over heats with AC on and under load. Car has 70,000 km on it.

OE radiator? Folks on the old forum had alot of QC issues with the aftermarket.


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[0-60motorsports]

OE radiator? Folks on the old forum had alot of QC issues with the aftermarket.


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Yes OE BMW radiator

[yhp2009]

So im assuming the bluebus readout matched the dash coolant temp?
Also the problem seems to be focused on the AC components. Although the condenser is new could be faulty could try out swapping out with a known working unit.
Sorry to hear about the gremlins. Hope you figure it out eventually

[eacmen]

So im assuming the bluebus readout matched the dash coolant temp?
Also the problem seems to be focused on the AC components. Although the condenser is new could be faulty could try out swapping out with a known working unit.
Sorry to hear about the gremlins. Hope you figure it out eventually

If the AC blows cold then the condensor is doing its job. I might check that the A/C system is charged with the correct level of refrigerant.

If it only happens at idle in the driveway but then cools down on the road my next focus would be on airflow over the rad/condensor. Maybe the pusher fan isn't running at full speed?

I will say I was chasing similar issue, and replacing the condensor didnt help. I ended up having to add back in the factory heat/shield and ducting for the rad since it was removed by a previous owner. But it sounds like you still have all the original ducting in place.


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[0-60motorsports]

So im assuming the bluebus readout matched the dash coolant temp?
Also the problem seems to be focused on the AC components. Although the condenser is new could be faulty could try out swapping out with a known working unit.
Sorry to hear about the gremlins. Hope you figure it out eventually

The condenser is brand new too. Yes the bluebus shows the temps going up to 98c.

[0-60motorsports]

If the AC blows cold then the condensor is doing its job. I might check that the A/C system is charged with the correct level of refrigerant.

If it only happens at idle in the driveway but then cools down on the road my next focus would be on airflow over the rad/condensor. Maybe the pusher fan isn't running at full speed?

I will say I was chasing similar issue, and replacing the condensor didnt help. I ended up having to add back in the factory heat/shield and ducting for the rad since it was removed by a previous owner. But it sounds like you still have all the original ducting in place.


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Correct everything is in its place. Nothing has been modified. I even removed the performance pulleys and installed all brand new pulleys and tensioners etc. AC blows cold, no problems. Pusher fan is working perfectly as mentioned before too. I am at a loss, angry and frustrated. I can’t keep throwing money at the issue as I have other responsibilities. So sad.

[yhp2009]

But the problem only activates when the AC is on no?
If so i assume there is something about the AC system that is causing the issue. Perhaps the condenser is getting hotter than it normally should and since its sandwiched against the radiator it can be a factor?

[0-60motorsports]

But the problem only activates when the AC is on no?
If so i assume there is something about the AC system that is causing the issue. Perhaps the condenser is getting hotter than it normally should and since its sandwiched against the radiator it can be a factor?

It could be if it was old but it’s new.


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[yhp2009]

AC Receiver Drier is another component to check out. Its relatively cheap and its a filter or sorts to clean the refrigerant from contaminants.
Supposedly needs to be replaced anytime the AC system is opened up i.e. condenser replacement. And has a very finite lifecycle that requires replacement
I dont know if this is something you already considered but seems like a cheap fix

[0-60motorsports]

AC Receiver Drier is another component to check out. Its relatively cheap and its a filter or sorts to clean the refrigerant from contaminants.
Supposedly needs to be replaced anytime the AC system is opened up i.e. condenser replacement. And has a very finite lifecycle that requires replacement
I dont know if this is something you already considered but seems like a cheap fix

I’ll do that once they check the AC system tomorrow. Thanks.

[Rudbari]

I hope you solve your issue soon

[0-60motorsports]

I am going to change out the dryer today possibly and then check how the car is tomorrow in the afternoon. Let’s see what happens when we recover the AC gas today and see if it is low or normal. The AC performance is perfectly fine.