AC Issues in Rain

[MyG80Ride]

It's not backing up and freezing. If there were a clog, the water would just spill out on the passengers feet eventually. It is freezing on the evaporator itself, before it can ever drip into the drip pan. This is because your new thermistor has failed, or was bad before they ever installed it. When the thermistor is working correctly, it is impossible for anything to freeze up, because it causes the compressor to stop pumping if the temperature at the evaporator gets to 35 degrees. You have to get down to 32 for it to freeze.
You are chasing the wrong problem.

I had 2 thermistor installed and both were bad before issue was corrected.

 

[ctrcbob]

When I first moved to my Lake County Florida, there were TWO shops nearby that specialized in A/C problems. Now both gone. There is an Indy shop close by but they are not a/c only. Full service repairs. I have yet to try them.

 

[TinsleyC]

bubbaG80Sport, I noticed you said you had the temp set to 70 and the fan on low. I typically just press Auto and set the temp to where I'm comfortable, pointing the vents away from me. I think of it as a home AC system - let it do it's thing.

Do you think running your fans faster might help keep it from freezing up?

 

[EdP]

bubbaG80Sport, I noticed you said you had the temp set to 70 and the fan on low. I typically just press Auto and set the temp to where I'm comfortable, pointing the vents away from me. I think of it as a home AC system - let it do it's thing.

Do you think running your fans faster might help keep it from freezing up?

It may delay but I don't think it will stop it. Of course, outside temperature and humidity come into play also.

 

[bubbaG80Sport]

bubbaG80Sport, I noticed you said you had the temp set to 70 and the fan on low. I typically just press Auto and set the temp to where I'm comfortable, pointing the vents away from me. I think of it as a home AC system - let it do it's thing.

Do you think running your fans faster might help keep it from freezing up?

Before the issue started occurring I left temp at low and just adjusted the fan speed to my comfort as the car cooled down. Setting temp at 70 was a recent change to see if it prevented the problem, which it did not.

Next time issue occurs I'm going to leave car running and see if the A/C compressor is cycling on/off more than expected. Right now my hypothesis is low refrigerant level.

 

[EdP]

Before the issue started occurring I left temp at low and just adjusted the fan speed to my comfort as the car cooled down. Setting temp at 70 was a recent change to see if it prevented the problem, which it did not.

Next time issue occurs I'm going to leave car running and see if the A/C compressor is cycling on/off more than expected. Right now my hypothesis is low refrigerant level.

That is a symptom of low level. On my car, that was the original test and they said it was OK. Much later though, they did the evacuation and refill that fixed the problem. My guess is they were not able to accurately test the level and at the speed they ran the text everything seemed normal.

 

[bubbaG80Sport]

My hypothesis is the refrigerant level is at the low end of acceptable amount because the issue is only occurring after continuously running the A/C for ~>45 minutes. The problem has not gotten worse since initially discovered (~2 years ago) as it's not occurring at a sooner/shorter period of time. This indicative of there NOT being a refrigerant leak in the A/C system.

If/when the issues re-occurs (I don't use A/C nor drive for >= 45 minutes very often), I'll check the A/C compressor engagement/disengagement frequency. If it's cycling frequently/excessively it's another data point pointing to low refrigerant level.

Another hypothesis is a bent/crimped/kinked A/C line restricting refrigerant flow. There is a A/C line near front driver side/coolant overflow tank that has a 90 degree bend that looks kinked. I speculate it may have been bent during engine removal/reinstall for the turbo oil line recall/fix several years ago. Below is a picture from front of car, but I need to obtain a picture from the side to show the area where it looks kinked/restricted. Bend is between black bolt and black test port.

If someone in this forum, preferably with a 2018 G80 3.3T Sport like mine, could provide a picture of theirs for reference it would be much appreciated. A picture from passenger side front tire to driver side front tire angle would be best.

 

[joegr]

...Next time issue occurs I'm going to leave car running and see if the A/C compressor is cycling on/off more than expected. Right now my hypothesis is low refrigerant level.

These cars don't have clutches that go on/off. The compressor is always driven by the belt when the engine is running. Instead, there is an electric valve at the back of the compressor that controls how much the compressor pumps, from nothing to 100%. However, it is not just an on/off thing. For example, it might set it to 50%.

Low refrigerant level will make it way more likely for the evaporator to partially freeze (one part of it will get colder than the rest), but still this is only possible if the thermistor has failed.

 

[bubbaG80Sport]

Low refrigerant level will make it way more likely for the evaporator to partially freeze (one part of it will get colder than the rest), but still this is only possible if the thermistor has failed.

I have replaced the thermistor. I have heard the reports of the replacement thermistors also being bad, but I tested old and new thermistor (post #118) and they were both within specifications (post #110). 34F is very close to freezing temperature and the thermistor signal/interpretation by car "computer" is not exact/precise. I suspect the car is not closing the A/C compressor electric valve in time to prevent the heat exchanger from frosting/icing up.

High humidity will also make the heat exchanger frost/ice up more frequently and at higher ambient temperatures. Think cold glass of your favorite beverage on a humid/muggy day. Problem seems more prevalent/occurs quick on high humidity days.

 

[G80Ultimate Don]

I have replaced the thermistor. I have heard the reports of the replacement thermistors also being bad, but I tested old and new thermistor (post #118) and they were both within specifications (post #110). 34F is very close to freezing temperature and the thermistor signal/interpretation by car "computer" is not exact/precise. I suspect the car is not closing the A/C compressor electric valve in time to prevent the heat exchanger from frosting/icing up.

High humidity will also make the heat exchanger frost/ice up more frequently and at higher ambient temperatures. Think cold glass of your favorite beverage on a humid/muggy day. Problem seems more prevalent/occurs quick on high humidity days.

Same problem with my 2018 G80 with Ultimate package.
Car was in the shop for two weeks so they could 1) witness the problem, 2) waited for the backordered replacement thermistor, and 3) installed the replacement thermistor. No courtesy car provided during this extended repair period. The "fix" didn't work. Same exact problem literally the next day.
Took the car back in. Service Manager suggested evactuating and refilling the freon. Charged me $190 because the factory won't cover replacement freon, even though this was the recommended fix for their acknowledged AC problem.
Makes one want to dump this vehicle brand!

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[salvageking]

Have a 2015 Genesis which had the same problem - blowing fog when its humid out, coils frost over and then no airflow, but seems to work after its turned off for 3-5 minutes and then restarted.

First, I changed the thermistor which seemed to help with the icing problem, however then it just wouldn't get cold on the drivers side. Ice cold on the passenger's side but warm on the drivers side. Before going down a rabbit hole of the blend door, I checked the low side pressure which was low. I recharged it with a $40 of AC Pro from WalMart and now it blows ice bricks even in 90 degree heat.

My guess is that when the evaporator would ice from low refrigerant - it should have been cut off until it melted but perhaps the thermistor was bad or it was too high up in the coil for it to be frosted over. I should have investigated the refrigerant first - unclear why a 7 year old car has low refrigerant, but that's one of many problems with this car lol. Hope this is helpful for someone.

 

[EdP]

Same problem with my 2018 G80 with Ultimate package.
Car was in the shop for two weeks so they could 1) witness the problem, 2) waited for the backordered replacement thermistor, and 3) installed the replacement thermistor. No courtesy car provided during this extended repair period. The "fix" didn't work. Same exact problem literally the next day.
Took the car back in. Service Manager suggested evactuating and refilling the freon. Charged me $190 because the factory won't cover replacement freon, even though this was the recommended fix for their acknowledged AC problem.
Makes one want to dump this vehicle brand!

You should have complained to Genesis customer service. Yes, that seems to be the proper fix though. Worked on mine.

 

[XappspecR]

I too have been playing the frozen evaporator/bad thermistor game with my Genesis dealer. It's took several visits for them to diagnose the problem, and I had to authorize the service advisor to drive it home 1 hour from the dealership. That's the only way they could replicate it. It's received 2 refrigerant recharges (they didn't specify if they evacuated and weighed in the proper amount, but I'll be asking next time), and 1 new thermistor.

After the thermistor replacement I got the car back again last week and left for a trip to Colorado the next day, with fingers crossed.

Big mistake.

Within 1 hour of leaving home I started having to cycle the compressor off/on. Eventually I was doing it 30 to 45 minutes. 10 minutes with it off would defrost the evap enough to give me 30-45 minutes of good air flow. The problem continued even in the cooler, dry air of Colorado. I did this for 20+ total hours of driving during the trip. FML. As C3PO said, we seem to be made to suffer. It's our lot in life!

The car is going back to the dealer on Monday. I'll request that they replace the thermistor again, and evacuate then carefully refill and measure the refrigerant going back in.

 

[EdP]

I too have been playing the frozen evaporator/bad thermistor game with my Genesis dealer. It's took several visits for them to diagnose the problem, and I had to authorize the service advisor to drive it home 1 hour from the dealership. That's the only way they could replicate it. It's received 2 refrigerant recharges (they didn't specify if they evacuated and weighed in the proper amount, but I'll be asking next time), and 1 new thermistor.

After the thermistor replacement I got the car back again last week and left for a trip to Colorado the next day, with fingers crossed.

Big mistake.

Within 1 hour of leaving home I started having to cycle the compressor off/on. Eventually I was doing it 30 to 45 minutes. 10 minutes with it off would defrost the evap enough to give me 30-45 minutes of good air flow. The problem continued even in the cooler, dry air of Colorado. I did this for 20+ total hours of driving during the trip. FML. As C3PO said, we seem to be made to suffer. It's our lot in life!

The car is going back to the dealer on Monday. I'll request that they replace the thermistor again, and evacuate then carefully refill and measure the refrigerant going back in.

Evacuation seems to be the key. Low refrigerant can cause freezing and mine was checked the first time and they said it was good. Evidently that was not the problem. The Genesis field engineer said to evacuate and that worked. I took a 2200 mile trip a week after and it was fine.

 

[XappspecR]

Evacuation seems to be the key. Low refrigerant can cause freezing and mine was checked the first time and they said it was good. Evidently that was not the problem. The Genesis field engineer said to evacuate and that worked. I took a 2200 mile trip a week after and it was fine.

I couldn't talk them in to replacing the new thermister yet, but they did evacuate and recharge the refrigerant. 650 grams is the spec and it was 80 grams low.

Hopefully that fixes it. We shall see. Just got it back today.

 

[EdP]

I couldn't talk them in to replacing the new thermister yet, but they did evacuate and recharge the refrigerant. 650 grams is the spec and it was 80 grams low.

Hopefully that fixes it. We shall see. Just got it back today.

That low could cause problem. Did they put dye in? They did with mine so if it happens again they may be able to find the problem.

 

[XappspecR]

That low could cause problem. Did they put dye in? They did with mine so if it happens again they may be able to find the problem.

Yes they did. I'm taking it back in a few days to let the tech have look around.

 

[bubbaG80Sport]

As posted in this thread I've been having the issue with A/C airflow decreasing and temperature increasing after ~45 minutes of running A/C. I've replaced the thermistor. Testing old and replacement thermistor both were within specifications. I still experienced the A/C issue after the thermistor replacement. I don't see the problem frequently because I drive >30 minutes infrequently.

I took car in to my local repair shop to troubleshoot the issue this weekend. Their diagnoses was the refrigerant level was low. They added 111.4 grams of R1234yf refrigerant (capacity is 630 +/- 25 grams). They also added UV dye to determine if/where there may be a refrigerant leak. A/C is blowing cooler air (58F) now (not to bad before). Next time I take a +45 minute drive w/ A/C I'll report back. I hypothesize dealer didn't fully fill/seal A/C system the 2x the engine was pulled (Turbo oil line and rear main seal leak repairs).

BTW,
This new R1234yf refrigerant is extremely expensive (~$100USD/lb) compared to HFC/R-134 (~$5USD/lb). HFC/R-134a replaced the original CFC/R-12 ("Freon") refrigerant.

Reference material

'Repair U': R-1234yf not going away, so auto body repairers, insurers need to be ready - Repairer Driven News

Collision repairers and insurers need to prepare for the additional time and cost associated with the R-1234yf refrigerant becoming more common in vehicle air conditioning...

www.repairerdrivennews.com

 

[XappspecR]

So far the correct refrigerant level seems to have fixed the problem for me. I've been driving it in very hot, humid, and rainy conditions for about a week now, with several drives of 45+ minutes.

As mentioned earlier they replaced the thermistor as well, but the problem persisted after that so it's unknown if that was necessary.

Fingers crossed!

 

[G-715297]

thought I needed new AC or heat or fan motor....but on a wet night the AC, heat and vents didnt seem to work. The windows were clear and you could hear the blower.....it was whatever the technology is to direct the airflow to keep windows from fogging. Today is dry and problem is fixed.