[whyzee125]

Hey guys,

About a month ago, I started getting an awful smell when I turn on the a/c. It's kind of a sweet, chemical smell but it's hard to describe the exact smell as you get used to it after a few whiffs then can't notice it. Definitely not a moldy smell however and definitely not a coolant smell.

I took the car into the shop and they said it smells like refrigerant and is likely a bad evaporator core but cannot be sure without pulling the dash. Total price to replace the evaporator is $2,600 and roughly $2,000 of that is labor so i'd hate to spend $2k to pull the dash only to find out that's not the issue.

The a/c has been recharged once about 5 years ago and was low again, although it still blows cold. It passed a leak test so it must be a very small leak but the smell is what concerns me. in addition to it being annoying, I can't imagine that's good to breathe in.

I'd pay $2,600 to fix it if I knew for sure that was the issue but I would not be happy about paying $2k just to check.

Thoughts?

[gbalthrop]

1) R-134a is basically odorless; PAG refrigeration oil has SOME odor;

2) Antifreeze (Ethylene Glycol) has a sweet odor; open your coolant reservoir and compare;

3) Heater Cores often develop "pin-hole leaks" after 10 or 15 years, particularly if Coolant NOT changed every 3 to 4 years to reduce acidity/ corrosion;

4) Coolant leaks out of small leak in heater core during warm engine operation but mostly after Hot shutdown. Coolant collects on core and pan beneath, and when Blower is first operated on startup, you get a strong "whiff" of coolant odor;

5) HOW do you know you are low on Refrigerant (R-134a)? What pressure tests were done? If the refrigeration system was "recharged" 5 years ago and still cools properly, there is NO significant leak, and what you are smelling is NOT R-134a.

6) ANY SHOP that tells you that they have to dismantle the Interior to know if the Evaporator is leaking should be AVOIDED. The Evaporator CAN/ SHOULD be pressure-tested BEFORE dismantling ANY interior.

7) If your Refrigeration System needs "Re-charging", you can get a 12-oz can of R-134a at Walmart for $5. If you need a Can Tap, $12. If you want a Can Tap with Gauge, $17. ALWAYS recharge SLOWLY, using Pressure & Temperature Chart for R-134a, and proper Gauge(s) to avoid overcharge which can damage the system.

Here endeth the "Thoughts"
George

[whyzee125]

Originally Posted by gbalthrop

1) R-134a is basically odorless; PAG refrigeration oil has SOME odor;

2) Antifreeze (Ethylene Glycol) has a sweet odor; open your coolant reservoir and compare;

3) Heater Cores often develop "pin-hole leaks" after 10 or 15 years, particularly if Coolant NOT changed every 3 to 4 years to reduce acidity/ corrosion;

4) Coolant leaks out of small leak in heater core during warm engine operation but mostly after Hot shutdown. Coolant collects on core and pan beneath, and when Blower is first operated on startup, you get a strong "whiff" of coolant odor;

5) HOW do you know you are low on Refrigerant (R-134a)? What pressure tests were done? If the refrigeration system was "recharged" 5 years ago and still cools properly, there is NO significant leak, and what you are smelling is NOT R-134a.

6) ANY SHOP that tells you that they have to dismantle the Interior to know if the Evaporator is leaking should be AVOIDED. The Evaporator CAN/ SHOULD be pressure-tested BEFORE dismantling ANY interior.

7) If your Refrigeration System needs "Re-charging", you can get a 12-oz can of R-134a at Walmart for $5. If you need a Can Tap, $12. If you want a Can Tap with Gauge, $17. ALWAYS recharge SLOWLY, using Pressure & Temperature Chart for R-134a, and proper Gauge(s) to avoid overcharge which can damage the system.

Here endeth the "Thoughts"
George

Thank you so much for the reply!

1) I've had coolant leaks/coolant smell many times before on several BMWs, and this is definitely not a coolant smell.

3) My coolant has been changed at every OFHG leak or rad hose failure, so about once a hear

4) They hooked my car up to gauges and said the refrigerant is low (they gave me the pounds vs spec but I don't have the paperwork with me)

5) I agree, they're a good shop but I wasn't happy with having to pull the interior apart. But they ran a pressure test on the whole system for an hour and it passed. So seems like I have a tiny leak.

One additional note: I took the under glovebox panel off to make sure the dealer actually did my blower motor wiring harness recall. There's a brown puddle of oil on the sound insulation. I'im not sure if it's PAG oil or if it's lube from the blower motor.

[gbalthrop]

Originally Posted by whyzee125

... They hooked my car up to gauges and said the refrigerant is low (they gave me the pounds vs spec but I don't have the paperwork with me)... they ran a pressure test on the whole system for an hour and it passed. So seems like I have a tiny leak.
One additional note: I took the under glovebox panel off to make sure the dealer actually did my blower motor wiring harness recall. There's a brown puddle of oil on the sound insulation.

I would be interested in knowing exactly HOW they tested with manifold gauges:
1) Static Test after engine OFF for 1 hour or more?
2) Pressures measured with engine running, Compressor Pumping, and ambient temp at that time?

I would also be interested in knowing HOW "they ran a pressure test on the whole system for an hour" and what the findings were. As stated earlier, IF still cooling reasonably well after Re-Charge FIVE years ago, you have NO significant leak.

Since there is NO "Odor" digital file you can attach, we can ONLY guess about the source of the smell, but odds are excellent it's NOT R-134a or PAG (refrigeration) oil.

As for oil on Trim Panel insulation below Blower Motor, that is NOT where any oil from Evaporator coil would go. There are condensate drains from the tray beneath the Evaporator Coil, and the Blower discharge is INTO the Evaporator Coil. Did you do a "Sniff-test" on the "oil puddle" on the Trim Panel Insulation?

You seem to have a reasonable understanding of HOW your system works, and can reason for yourself WHAT makes sense and what does NOT. Either your "Shop" lacks the same ability to reason, OR there's something left out of this discussion. The SIMPLE FACTS are:
1) Your refrigeration system charge of R-134a is 20.8 Ounces = 1.3 pound
2) SOME of that refrigerant is lost over time
3) Cooling adequately FIVE years after last "Re-charge" is proof that there is NO abnormal leak of refrigerant.

If you had INPA, you could quickly and easily read/view "Refrigerant Pressure" (AND Evaporator Temp) and KNOW how the Refrigeration system was performing. If you had either a Can Tap with Gauge (~$20) or Manifold Gauges ($35), you could diagnose it yourself with help from Forum members, and add refrigerant ($5 for 12-oz can) when needed.

What Forum members CANNOT do is identify the source of the ODOR. However, given the "clue" of the oil spot beneath the blower, and the smell being WORST when you first start the Blower running, I would suggest taking 10 minutes to remove the six 8mm screws that hold the Upper Microfilter Housing, and inspect the microfilter and the air plenum opening on the Right (US Passenger) side, over top of the blower.

There are NO moving parts, and the ONLY thing that can be "messed up" is NOT getting the housing correctly re-attached to the air plenum openings.

George

[eljay]

Did the shop refill refrigerant? If yes, did they add dye?
If yes, check around the engine bay A/C lines and condenser for leaks with UV light, but especially this area here: https://www.e90post.com/forums/showthread.php?t=1851709

I had a PAG oil smell in the cabin and ran out of refrigerant completely twice over a period of two months. Finally, came across the thread above and changed that line and got a refill. So far, all is well and the pressure holding for 3 weeks.

And yes, make sure they use the 1-hour status pressure test as pointed above and ask them to check/listen in the area by the passenger side frame rail.

[lowrydr310]

Originally Posted by eljay

I had a PAG oil smell in the cabin and ran out of refrigerant completely twice over a period of two months.

Does the PAG oil smell like a band-aid? I get a whiff of band-aid smell occasionally when I first turn the AC on. I've been wondering about leaks myself, though mine blows cold.

[mainbearing]

At least based on the description that sounded more like coolant, but you are sure that is not it.

If the leak is very small, you probably are not smelling PAG every time you turn on the AC for the past month.

Is the car using coolant? Could it be something that came in from the engine bay?

Transmission fluid smell maybe? I know when I freshly filled using Valvoline Maxlife it had a particular smell (a sweet, poignant smell) that would come in through the vent at blower start for a few days.

The E90 is particularly bad at letting in engine bay fumes in, even when set to recirc mode.

Originally Posted by whyzee125

Hey guys,

About a month ago, I started getting an awful smell when I turn on the a/c. It's kind of a sweet, chemical smell but it's hard to describe the exact smell as you get used to it after a few whiffs then can't notice it. Definitely not a moldy smell however and definitely not a coolant smell.

Thoughts?

[mainbearing]

Also, a shop would have an electronic sniffer. I am surprised they did not use that with OP's car. If a leak was so small that a detector could not smell it (or a no-leak pressure test), maybe it was not AC?

There are all kinds of cheap versions on Amazon like this $21.99 one:

https://www.amazon.com/LotFancy-Refr.../dp/B00P90BKOG

Harbor Freight has a $69.99 version:
https://www.harborfreight.com/electr...tor-92514.html

Originally Posted by lowrydr310

Does the PAG oil smell like a band-aid? I get a whiff of band-aid smell occasionally when I first turn the AC on. I've been wondering about leaks myself, though mine blows cold.

[whyzee125]

Originally Posted by mainbearing

At least based on the description that sounded more like coolant, but you are sure that is not it.

If the leak is very small, you probably are not smelling PAG every time you turn on the AC for the past month.

Is the car using coolant? Could it be something that came in from the engine bay?

Transmission fluid smell maybe? I know when I freshly filled using Valvoline Maxlife it had a particular smell (a sweet, poignant smell) that would come in through the vent at blower start for a few days.

The E90 is particularly bad at letting in engine bay fumes in, even when set to recirc mode.

Originally Posted by mainbearing

Also, a shop would have an electronic sniffer. I am surprised they did not use that with OP's car. If a leak was so small that a detector could not smell it (or a no-leak pressure test), maybe it was not AC?

There are all kinds of cheap versions on Amazon like this $21.99 one:

https://www.amazon.com/LotFancy-Refr.../dp/B00P90BKOG

Harbor Freight has a $69.99 version:
https://www.harborfreight.com/electr...tor-92514.html

Thanks for the reply. Trans fluid is still original and not leaking (need to change it but its not that smell, my old e90 burst a trans cooler line and I remember the smell). To me, coolant has a distinct odor almost like maple syrup and this is definitely not coolant. Car is not losing any fluids but the a/c still blows cold too which is really weird. I thought about trying one of those sniffers since the shop did not. They said the refrigerant was low but it passed a leak test, so I'm guessing it has a very tiny leak but the odor is strong and started literally overnight. It's not coming from the engine bay but it's weird bc I can't quite smell it long enough to think of the words to describe it as you get used to the smell quickly. Everytime I turn on the a/c it's nasty for a second then I get used to it. The windows are a bit hazy. It's significantly more noticeable with the a/c on than with the heat but it's there a bit either way. The shop said they've encountered cars with the moldy evaporator issue and my smell is different. One tech said it "smells like refrigerant" but some seem to say refrigerant does not have a smell.

Thankfully, the weather is changing here so I'll see if it goes away once I only use the heat for a season. Maybe next summer my freon will be empty and it'll be easier to pinpoint lol. I'll prob try one of those sniffers in the meantime.

[whyzee125]

Originally Posted by eljay

Did the shop refill refrigerant? If yes, did they add dye?
If yes, check around the engine bay A/C lines and condenser for leaks with UV light, but especially this area here: https://www.e90post.com/forums/showthread.php?t=1851709

I had a PAG oil smell in the cabin and ran out of refrigerant completely twice over a period of two months. Finally, came across the thread above and changed that line and got a refill. So far, all is well and the pressure holding for 3 weeks.

And yes, make sure they use the 1-hour status pressure test as pointed above and ask them to check/listen in the area by the passenger side frame rail.

They did not refill it. Could you describe what PAG oil smelled like by any chance? I'll check that area under the hood as this is driving me nuts, thank you.

They did do the pressure test but it held consistently for as long as they had it hooked up which is super odd lol

[eljay]

Originally Posted by whyzee125

They did not refill it. Could you describe what PAG oil smelled like by any chance? I'll check that area under the hood as this is driving me nuts, thank you.

They did do the pressure test but it held consistently for as long as they had it hooked up which is super odd lol

Your description of "sweet chemical" smell sounds like PAG oil.

[eljay]

Originally Posted by lowrydr310

Does the PAG oil smell like a band-aid? I get a whiff of band-aid smell occasionally when I first turn the AC on. I've been wondering about leaks myself, though mine blows cold.

Never thought of band-aids, but yes, that us actually a pretty good comparison. haha

[e91Owner]

Originally Posted by whyzee125

They did not refill it. Could you describe what PAG oil smelled like by any chance? I'll check that area under the hood as this is driving me nuts, thank you.

They did do the pressure test but it held consistently for as long as they had it hooked up which is super odd lol

After the car has sat for a while, press the high pressure valve to release a little refrigerant which will also release some oil. You could do either line, but the high pressure port is at the front of the engine and is more accessible on most models. You'll smell it instantly. Almost indescribable, but it has an acrid stink-bug smell to me.

[nsjames]

Originally Posted by mainbearing

Also, a shop would have an electronic sniffer. I am surprised they did not use that with OP's car. If a leak was so small that a detector could not smell it (or a no-leak pressure test), maybe it was not AC?

There are all kinds of cheap versions on Amazon like this $21.99 one:

https://www.amazon.com/LotFancy-Refr.../dp/B00P90BKOG

Harbor Freight has a $69.99 version:
https://www.harborfreight.com/electr...tor-92514.html

this.
any shop that does competent ac work will have a very sensitive leak detector.
have them park it overnight, then shove the detector in the vents and start the car.
instant results.

[whyzee125]

Thanks guys! I'll call around and see which shops can do a sniffer test or I'll just buy one. May try the valve trick too to release a little and see if the smell matches up.

[whyzee125]

I purchased a sniffer on eBay and it confirmed my suspicions.

I tried it on my Dodge truck first and couldn't get it to siren anywhere inside the truck or under the hood. On my e90, it didn't pick anything up under the hood but putting it close to the vents immediately made it go crazy. I also put the AC on recirculate just to be sure it's not drawing any outside air but any time you put it within 6 inches of the vents, it goes off like crazy so it must be a leaking evaporator or one of the fittings.

[whyzee125]

Wow, just realized it's literally been 2 years since I started this thread. I can't believe it's been that long.

Funny thing is, the AC is still ice cold but the refrigerant does read that it's quite low.

[lowrydr310]

When I acquired my 330i three years ago, there was always a smell when I first turned the blower fan on which smelled like band aids. My understanding is this is the distinct smell of PAG oil. Three years later and running the AC compressor every day, it still blows ice cold so if there is any leak it must be very minor.

[whyzee125]

Originally Posted by lowrydr310

When I acquired my 330i three years ago, there was always a smell when I first turned the blower fan on which smelled like band aids. My understanding is this is the distinct smell of PAG oil. Three years later and running the AC compressor every day, it still blows ice cold so if there is any leak it must be very minor.

Sounds like exactly my issue! I'm going to put some UV dye in it to be sure whether it's the evaporator or a fitting then fix it.

I'm very sensitive to exposure to chemicals, mold, etc. so I don't want to be breathing anything in that can be avoided.

I'll update with the results after the the repair.

[mainbearing]

Glad you FINALLY pinpointed what the problem may be.

Anyway, the few pictures others posted seem to suggest Valeo evaporator is the problematic one (because they were all Valeo evaps). I do not know, maybe Denso is bad as well, or maybe Denso is the Gold Standard for AC systems. Let us know what your shop finds.

They will have to disconnect the expansion valve in the engine bay. Maybe have them put in a new one and new o-rings there too. Not sure if that model year has a replaceable condenser desiccant bag, if so replace that as well.

A member's problem Valeo evap:

https://www.e90post.com/forums/showthread.php?t=1125895