Overheating while running A/C

[yhp2009]

Well No because it is working perfectly fine and my tech refused to in a way, which is good for my pocket. He really is great and the reason I have stuck with him for the past 14 years or so.

Fair enough. Thanks again for keeping us updated and knock on wood for the new idea. If it is the alternator that would be a relief and a head scratcher for sure.

[0-60motorsports]

Thats interesting for sure. BTW did you end up replacing the compressor as well? I remember that was where you left off last?

Well No because it is working perfectly fine and my tech refused to in a way, which is good for my pocket. He really is great and the reason I have stuck with him for the past 14 years or so.

[yhp2009]

Thats interesting for sure. BTW did you end up replacing the compressor as well? I remember that was where you left off last?

[0-60motorsports]

Another thing we were discussing is that I have and hasan from HTE have been running the CSL battery for a while. Me ten years. I switched to the bigger stock battery last year since the CSL battery wasn’t available at the time. My tech and we think that due to the smaller battery it effected the alternator life. We run AC almost all year around and it gets hot and humid here up to 125f. Just a theory.

[Ramo]

Update:

So today we might have discovered the cause of the overheating. Message from my tech who has been working on my car for more than 14 years:


“Bro, something unbelievable in your car M3, I told them to keep the car engine running while under the sun, they did yesterday and when about to overheat put the battery jump start cable that connected from another car that the engine is running then it solve the overheating, the possible cause is weak alternator, the voltage is ok possible the amperage is low and due of a/c load the aux fan became not efficient to push more air.”

New valeo alternator ordered from FCPeuro.

My battery wasn’t holding a charge anymore since it was around 7 years old so I replaced it. Once in a while I still get a “low battery” message on my uniden r3 radar detector even with the new battery and the car overheats (on hot days 95+) with the AC on. Wondering if it’s the alternator as well.

[eacmen]

Update:

So today we might have discovered the cause of the overheating. Message from my tech who has been working on my car for more than 14 years:


“Bro, something unbelievable in your car M3, I told them to keep the car engine running while under the sun, they did yesterday and when about to overheat put the battery jump start cable that connected from another car that the engine is running then it solve the overheating, the possible cause is weak alternator, the voltage is ok possible the amperage is low and due of a/c load the aux fan became not efficient to push more air.”

New valeo alternator ordered from FCPeuro.

Nice find. I would expect the voltage to drop when the aux fan kicked on if this was the case.

[0-60motorsports]

Update:

So today we might have discovered the cause of the overheating. Message from my tech who has been working on my car for more than 14 years:


“Bro, something unbelievable in your car M3, I told them to keep the car engine running while under the sun, they did yesterday and when about to overheat put the battery jump start cable that connected from another car that the engine is running then it solve the overheating, the possible cause is weak alternator, the voltage is ok possible the amperage is low and due of a/c load the aux fan became not efficient to push more air.”

New valeo alternator ordered from FCPeuro.

[0-60motorsports]

So while I was speaking to the tech today he was telling me when the car Overheats with the AC on he noticed two things. 1: the condenser heats up 2: the ac pressures increase, high side is almost at 300psi which is 50 over normal and low side is 30psi over normal.

This leads me to believe that it could be the compressor and even though the condenser is one year old I’ll change it out as it’s cheap enough. Waiting for final word and correct compressor pn from the shop so that I can order it if it is needed today.

[0-60motorsports]

Is the condenser touching the radiator? Did you reinstall the plastic shrouds (both of them)?
Is the radiator mounted properly and sitting on the mounts, properly and correctly secured?
Is your plastic under-tray installed?
It sounds like you replaced every component with BMW parts, correct? Not an OEM supplier but used the actual OE parts from the same manufacturer as BMW on that specific part (specifically for the thermostat and fan clutch/fans? (Speaking of which, did you replace the belt fan with a BMW part? If not, did you inspect it carefully for missing blades (they can be easy to miss if you check too quickly).
Out of curiosity, when the needle moves have you checked inlet/outlet temps at that moment?

Hey so I’ll try to answer your questions in the same order as you ask them.

No
Yes
Yes
Yes
Correct
Fan belts and pulleys and tensioner all brand new
Fan is brand new and so is fan clutch
The temps displayed vi the obd or can readout are 94c when it starts moving past half way mark and goes up to 98-99c when the needle is almost at 3/4 mark for the water temp


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[Rudbari]

Do leak down test it maybe something wrong with engine

[Icecream]

Yes we checked the pressures after recharge and it was perfect.

Coolant just changed a few weeks back just for this issue even though it was new and was tested to make sure the mixture was perfect.

This issue started way before randomly. The condenser is installed perfectly to oe specs as well.

Next will be changing the expansion valve.


Sent from my iPhone using Tapatalk

Is the condenser touching the radiator? Did you reinstall the plastic shrouds (both of them)?
Is the radiator mounted properly and sitting on the mounts, properly and correctly secured?
Is your plastic under-tray installed?
It sounds like you replaced every component with BMW parts, correct? Not an OEM supplier but used the actual OE parts from the same manufacturer as BMW on that specific part (specifically for the thermostat and fan clutch/fans? (Speaking of which, did you replace the belt fan with a BMW part? If not, did you inspect it carefully for missing blades (they can be easy to miss if you check too quickly).
Out of curiosity, when the needle moves have you checked inlet/outlet temps at that moment?

[0-60motorsports]

Expansion valve changed and same crap, still overheating. I’m at a loss. I don’t want to spend money on this issue any more but it has to be solved. Let’s see what tomorrow brings.

[0-60motorsports]

Yes we checked the pressures after recharge and it was perfect.

Coolant just changed a few weeks back just for this issue even though it was new and was tested to make sure the mixture was perfect.

This issue started way before randomly. The condenser is installed perfectly to oe specs as well.

Next will be changing the expansion valve.


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[Icecream]

Yes anything above 40c and car overheats with AC on. AC off the temp drops fast back to under half.

Since you recharged it, I am assuming you verified that high and low side pressures were within spec? That would more or less give you an idea of whether or not the compressor was functioning properly.
Did you do a coolant change and alter the mix ratio? What is your mix?
Did it start after changing the condensor? Maybe it was fitted incorrectly and is touching/too close to the radiator --> transferring heat to it instead of the air?
When exactly did this start to happen? Any major work the season before?

[0-60motorsports]

Same ambient temp?


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Yes anything above 40c and car overheats with AC on. AC off the temp drops fast back to under half.