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-   -   A/C Head Scratcher (https://www.bimmerfest.com/forums/showthread.php?t=1338013)

320kplus 07-10-2019 02:47 PM

A/C Head Scratcher
 
2013 E70 xDrive35i...
Air blows cold on driver's side, warmer on passenger side. Both sides are on the same temperature [60°] with Max button on. Is this indicative of low free on or something more troubling? Thanks in advance.

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Doug Huffman 07-10-2019 02:54 PM

1 Attachment(s)
Commonly a fouled side of the Hot-water Control Valve.

BMW IHKA HVAC is a hot water temperature controlled system with the engine heat radiator heat exchangers after down airstream the AC evaporator. The evaporator is always fully loaded and cabin set temperature(s) maintained by a PWM signal to the HCV from the IHKA control module / panel.

https://www.bimmerfest.com/forums/at...1&d=1562795751

BabyUnicornTaco 07-10-2019 03:26 PM

2 Attachment(s)
Quote:

Originally Posted by Doug Huffman (Post 13050303)
Commonly a fouled side of the Hot-water Control Valve.

BMW IHKA HVAC is a hot water temperature controlled system with the engine heat radiator heat exchangers after down airstream the AC evaporator. The evaporator is always fully loaded and cabin set temperature(s) maintained by a PWM signal to the HCV from the IHKA control module / panel.

https://www.bimmerfest.com/forums/at...1&d=1562795751



+1 on this. My guess would be heater control valve. There are a couple pretty easy ways to test. If the valve is getting stuck you could tap on the top of the HCV and see if it knocks loose and gives you cold air. This is how bad they get inside. Attachment 857715Attachment 857717


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320kplus 07-10-2019 04:12 PM

Quote:

Originally Posted by BabyUnicornTaco (Post 13050327)
+1 on this. My guess would be heater control valve. There are a couple pretty easy ways to test. If the valve is getting stuck you could tap on the top of the HCV and see if it knocks loose and gives you cold air. This is how bad they get inside. Attachment 857715Attachment 857717


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Uuuuuurgh. Thanks guys! Tough DIY? How long to swap out old for new? Part cost? Or... what should it run to have a shop do it? I think it just started. I just got this ride but didn't notice it before and the weather has been warm/hot/muggy...

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BabyUnicornTaco 07-10-2019 04:37 PM

This is the OE BMW replacement. You can go cheaper but the trend is that you get what you pay for. It's not a bad DIY. Good time to flush and replace all your coolant. FCPEuro will give you a lifetime warranty.

https://www.ecstuning.com/b-genuine-...e/64116910544/

1bad540 07-10-2019 06:47 PM

easy swap 15 min you can grab it and swap it out w some hose clamp pliers. Just had mine done but car was blowing cold on pass side and hot and cold at the same time on driver.

Masoe 07-10-2019 06:50 PM

Quote:

Originally Posted by 320kplus (Post 13050281)
2013 E70 xDrive35i...
Air blows cold on driver's side, warmer on passenger side. Both sides are on the same temperature [60°] with Max button on. Is this indicative of low free on or something more troubling? Thanks in advance.

Sent from my SM-N960U using Tapatalk

From my EXACT same experience...My Indy Evacuated the system ( I was low) and refilled the system with the proper amount of "refrigerant" and now both my sides blow COLD. They also put a dye in the system to see if there will be future leaks. They replaced the little pins (sorry dont know the name) in the filler valves as well. They said most people dont think to replace them and that's where the system can leak from. I would definitely try the Purge and Fill first...nominal cost and time. Good Luck! :thumbup:

robnitro 07-10-2019 08:05 PM

Schraeder valves, yeah can't change those until you evacuate system.

Masoe 07-10-2019 08:20 PM

lol...yup, those are the valves. Thanks:thumbup:

deroy 07-11-2019 12:40 AM

Quote:

Originally Posted by 320kplus (Post 13050365)
Uuuuuurgh. Thanks guys! Tough DIY? How long to swap out old for new? Part cost? Or... what should it run to have a shop do it? I think it just started. I just got this ride but didn't notice it before and the weather has been warm/hot/muggy...

Sent from my SM-N960U using Tapatalk

Yes DIY, esp on a straight 6. With the V8 it's really tight and fiddly. Hose clamps do a good job, but not perfect. Tuck some old towels in as backup.
As diagnosis of the valves; feel the two hoses leading to the firewall. In your case one should be hot.
I don't see how being low on refrigirant in the AC system would lead to your (strong) left/right contrast in temp output.

Doug Huffman 07-11-2019 04:16 AM

Quote:

Originally Posted by deroy (Post 13050707)
I don't see how being low on refrigirant in the AC system would lead to your (strong) left/right contrast in temp output.

It is an old wives’ tale. The tale is that only the evaporator nearest the expansion valve can carry load while the refrigerant charge is low. Be that as it may, and I have never seen a thermodynamic explanation, the BMW evaporator is folded so that the average cooling load is everywhere the same along the path from inlet to outlet.

1bad540 07-11-2019 05:21 AM

Its not an old wives tale, older ones when the refrig was low would blow cold driver warm passenger. my valve was bad but I had the system vac and refilled too. back to crispy cold.

Doug Huffman 07-11-2019 06:04 AM

Quote:

Originally Posted by 1bad540 (Post 13050833)
Its not an old wives tale, older ones when the refrig was low would blow cold driver warm passenger. my valve was bad but I had the system vac and refilled too. back to crispy cold.

All of your personal anecdotes do not add up to one empirical datum. It is an old wives' tale.

Zulu95 07-11-2019 06:41 AM

+1 E53: Cold/warm problem cured by evac/recharge. I did a temp fix with a wallyworld rattle can quick charge until I could get it into the shop for a complete check out. That was about 5 years ago still blowing cold. Old wives tale or not a recharge fixed the problem.

Doug Huffman 07-11-2019 06:54 AM

Quote:

Originally Posted by Zulu95 (Post 13050909)
+1 E53: Cold/warm problem cured by evac/recharge. I did a temp fix with a wallyworld rattle can quick charge until I could get it into the shop for a complete check out. That was about 5 years ago still blowing cold. Old wives tale or not a recharge fixed the problem. [/COLOR]

NO. No, the problem went away after the "recharge" not necessarily because of it. Post hoc ergo propter hoc is the weakest logic, just better than the arrow of time.

Masoe 07-11-2019 01:30 PM

OP...There has been a lot of discussion on this topic in the past (google it) and there are a LOT of people that have had this problem fixed by a purge and fill. I don't know the reason or have data on how it fixed my issue, and frankly I don't care because the issue was fixed and has been for years now. Try it and report back.

FWIW, this brings back one of the issues I had with the fuel pump relay causing my vehicle not to start when temps went below 32 degrees F. I had people saying they couldn't understand why it would fail and cause the vehicle not to start at a certain temperature, BUT it did! $18 dollars later (part replaced at dealer during warranty work) and I have NOT been stranded in the cold every since (others have benefited from this as well). I don't know why it worked, but it did.

vinsonr 07-14-2019 07:46 PM

OP,

Push this button: http://www.bavarianmw.com/images/boo...6/index.80.gif and dial the vent back to cool. It took me waaay longer than I care to admit to realize why I had warm air coming out of my driver's side....

Pic didn't show but it's the 'manual mode' button with 3 air vent arrows and a person sitting down.

http://www.bavarianmw.com/images/boo...6/index.80.gif

320kplus 07-14-2019 08:05 PM

Quote:

Originally Posted by vinsonr (Post 13054057)
OP,

Push this button: http://www.bavarianmw.com/images/boo...6/index.80.gif and dial the vent back to cool. It took me waaay longer than I care to admit to realize why I had warm air coming out of my driver's side....

Pic didn't show but it's the 'manual mode' button with 3 air vent arrows and a person sitting down.

http://www.bavarianmw.com/images/boo...6/index.80.gif

Bingo! Passenger side was set to warmer. Now it's fixed. I'm still going to have the cold air temp checked and see where I'm at.
All the best guys!

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Pete_NZ 07-15-2019 06:41 PM

Hahaa Love it when a fix performed in actual, live reality shows all the theorising and rationale based analysis and grandstanding arguments and "superior" assertions as worth the 2cents they are.

ard 07-15-2019 10:36 PM

Quote:

Originally Posted by Doug Huffman (Post 13050787)
It is an old wives’ tale. The tale is that only the evaporator nearest the expansion valve can carry load while the refrigerant charge is low. Be that as it may, and I have never seen a thermodynamic explanation, the BMW evaporator is folded so that the average cooling load is everywhere the same along the path from inlet to outlet.

Not true. This has been posted and explained.

brc5 07-16-2019 05:46 AM

Quote:

Originally Posted by Doug Huffman (Post 13050787)
It is an old wives’ tale. The tale is that only the evaporator nearest the expansion valve can carry load while the refrigerant charge is low. Be that as it may, and I have never seen a thermodynamic explanation, the BMW evaporator is folded so that the average cooling load is everywhere the same along the path from inlet to outlet.

It's not an old wives tale at all. I had the exact problem described, related to low refrigerant caused by a failing evaporator. The design of the evaporators means that the air coming off the entry point to the evaporator is colder than the air coming off the other side. When it is not working efficiently one side of the car gets cold air and the other gets warm air. It doesn't make sense but it's how it works out when you get a failing AC system and the internals of the BMW HVAC systems. Fix the problem and the air is cool out both sides again, without touching any heater parts.

Of course, you can have other problems that cause warm/cold air, but a failing AC system is absolutely one of the possibilities.

Doug Huffman 07-16-2019 05:48 AM

2 Attachment(s)
Evaporator inlet and outlet are on the same side.
https://www.bimmerfest.com/forums/at...1&d=1563284732

One may see in the cartoon cutaway of green piece 5 the inlet and outlet ports and the fold at the bottom of the image.

1bad540 07-16-2019 05:52 AM

some of us dont care to argue, especially when weve had over 20 bmws and your on your 1st!! lol

ard 07-16-2019 07:35 AM

Again...

https://www.bimmerfest.com/forums/sh...re#post9821452


At the end of the day, hundreds of people have seen this behaviour w low Freon. My comments on differential diagnosis stand....

320kplus 07-16-2019 07:47 AM

Quote:

Originally Posted by ard (Post 13055311)
Again...

https://www.bimmerfest.com/forums/sh...re#post9821452


At the end of the day, hundreds of people have seen this behaviour w low Freon. My comments on differential diagnosis stand....

Guys! Thank you all for your insight! No doubt we've all Learned something from just this one thread. This is exactly what these forms are for and about. ROCK ON!

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ard 07-16-2019 08:31 AM

Quote:

Originally Posted by 320kplus (Post 13055339)
Guys! Thank you all for your insight! No doubt we've all Learned something from just this one thread. This is exactly what these forms are for and about. ROCK ON!

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"we"? no. :angel:

But yes, rock on!

:thumbup:

320kplus 07-16-2019 09:04 AM

Quote:

Originally Posted by ard (Post 13055367)
"we"? no. :angel:



But yes, rock on!



[emoji106]

ROTFLMAO! Alrighty then!

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