[retrofast]

Hi all

Long time viewer first time caller (poster).

I have a 2006 e92 335i and I'm having a hell of a time with my AC. Any advice is welcome.

My AC loses its charge after about 2 weeks and stops blowing cold air gradually.

I had B4BMW, an independent BMW specialist in Glasgow (UK) do a recharge and dye test. They found no trace of the dye anywhere. The concluded it must be the condenser. Had a second opinion from an independent AC specialist and he said the same.

So I had B4BMW replace the condenser...and....same issue.

When charged, it works perfectly for about 10-12 days.

However, there is one hose connected to the condenser that has oil all over it's the end that connects to the condenser, there is no source for the oil from above.

The garage dismissed it as they found no dye there..

Any thoughts on if this could be the issue?

Cheers in advance.

[e90yyc]

What about the evaporator? If anything that’s the common failure point in the system. Not saying condenser wouldn’t fail, but my understanding is that evaporator replacement on these cars is basically an inevitability…

[retrofast]

Originally Posted by e90yyc

What about the evaporator? If anything that’s the common failure point in the system. Not saying condenser wouldn’t fail, but my understanding is that evaporator replacement on these cars is basically an inevitability…

Thanks for the reply.

Let's explore everything before we conclude that horrible possibility

How about this hose? Anyone have thoughts on the hose?

Then I will try the schrader valves and caps. (https://www.bimmerfest.com/threads/e...points.779399/)

"If the evap is leaking you'll almost always get fluorescent condensate dripping from the evaporator drain. " - none was found.

[e90yyc]

Originally Posted by retrofast

Thanks for the reply.

Let's explore everything before we conclude that horrible possibility

How about this hose? Anyone have thoughts on the hose?

Then I will try the schrader valves and caps. (https://www.bimmerfest.com/threads/e...points.779399/)

"If the evap is leaking you'll almost always get fluorescent condensate dripping from the evaporator drain. " - none was found.

Haha fair enough! And agreed—I hope that’s not the case. That also makes sense about seeing the dye in the drain, I just wasn’t positive if that was explored.

I guess it’s possible that hose could be leaking. I’m a bit surprised at the lack of dye though, especially if there’s oil around it. Dead serious here: What does it taste like? Does it taste like PAG oil or maybe something else?

[alpinec1984]

check the evap drain again for UV dye, it can take quite a bit of time and material to coat out all those parts then drip out. Or you may have the dreaded external evaporator leak.

[gbalthrop]

Originally Posted by retrofast

... 2006 e92 335i... AC loses its charge after about 2 weeks and stops blowing cold air gradually.
I had B4BMW, an independent BMW specialist in Glasgow (UK) do a recharge and dye test. They found no trace of the dye anywhere. They concluded it must be the condenser... [?]
So I had B4BMW replace the condenser...and....same issue.[?]
When charged, it works perfectly for about 10-12 days.
However, there is one hose connected to the condenser that has oil all over it's the end that connects to the condenser, there is no source for the oil from above. The garage dismissed it as they found no dye there...[?]

Questions:
1) Do you know HOW the "Specialist" recharged the system? Did he evacuate and carefully follow the "Vaccum" in the system for at least 30 minutes to see if there was a pressure change? If recharged system loses charge in 10-12 days, that's a SIGNIFICANT leak. A small Change in Vacuum SHOULD have been noted in 30 minutes, BEFORE wasting R-134a & Dye, his time, YOUR MONEY.

2) WHEN & HOW did "Specialist" do "dye test"? What type of "dye" was used? UV (Ultra-Violet) Dye? How long AFTER charging with the dye was the "Test" conducted? Same Visit? Who inspected, and WHAT was inspected?

3) Do you have Blacklight" & UV glasses for seeing the "flourescent" UV Dye (assuming that is what was used)?
https://www.amazon.co.uk/s?k=uv+dye+...s_ts-doa-p_3_6

4) When "Specialist" changed the Condenser, were new O-rings used? HOW MUCH Refrigeration Oil (PAG Oil) was added to system when Condenser was replaced? When they evacuated the system prior to recharge AFTER changing Condenser, did they make sure Vacuum was retained for at least 30 minutes?

5) If "garage" dismisses the oil leak: (a) has anyone there examined the oil deposits? (b) Has anyone there suggested a plausible CAUSE for the oil deposits, other than refrigeration oils (PAG Oil) leaking from Condenser Fitting?

Opinions about A/C systems are like "belly-buttons": EVERYONE has one.
I've maintained my own A/C systems for 50 years. I'm NO Pro, but I understand the basics of the system, have the tools, and take my TIME. A shop can't afford to do the latter -- that's "piddling".

I've NEVER had a leak in an Evaporator Coil. I've had leaks in O-rings, Schrader Valves, & Compressor Seals. I had a leaking hose or two on older systems (with OIL DEPOSITS at the leak site ;-). I've kept vehicles with operating A/C systems until they were 20 or 30 years old (Jag XJ-S & XJ-6/XJ-40). So that is the basis for the following "Opinion".

Most common leak points are O-rings and Schrader valves. Easy to fix. NOT so easy to diagnose. Requires evacuation & Recharge (AFTER testing for 30 minutes or more to see that NO Vacuum is lost). Best way I know is use a UV Dye. Run the system for a week or more. Then inspect for dye leaks with UV glasses & Light. Naked vision in daylight shows NADA. Your location of Refrigeration Oil per your photo is clear evidence of a leak, but if UV Dye was used, you would need a "Blacklight" and Yellow Glasses to see the "Greenish-Yellow" flourescent dye around the leak point.

If you've lost at least TWO (2) full charges of refrigerant in a month or so, you don't really need the dye. Just look for the OIL, like it appears you have already DONE.

Every Line or Hose has a fitting at the end. There is usually an O-ring at every fitting to a component such as the Condenser Inlet & Outlet fittings, Refrigerant Pressure Sensor near Washer filler Tube, Expansion Valve, Evaporator Inlet & Outlet, Compressor lines (High & Low pressure). Also check High & Low Side Schrader Valves at Quick-Connect ports; Compressor shaft seal; & stone damage to FRONT of Condenser coil (the tubes).

NEVER let anyone tell you that you need to have the Evaporator replaced WITHOUT personally observing a pressure test of the Evaporator BEFORE anything but the fittings are removed (test it in place). The car is virtually built around the Evaporator and most everything from the front seats forward has to be removed to get the Evaporator out.

You sound like you know something about A/C systems. Given the time and thought required to identify a leak source, I would suggest investing ~ $50 US or less, and several hours of your time, to try to find the leak yourself. Stuff sold on Amazon UK (or US ;-) is fine for DIY. The Tools needed: One Can of R-134a with UV Dye; Can Tap with Gauge; UV Dye kit (glasses & light). If your system still has SOME pressure > 1 bar, then air & moisture have NOT entered, just R-134a (AND PAG Oil) Lost.

Once you find the leak, you can likely fix it yourself with new O-rings or Schrader Valves, and THEN you'll need to evacuate, Test for Vacuum retention for ~ 1 hour, and recharge. If you do NOT have a vacuum pump (the expensive A/C DIY tool, unless you use a $20 US Air Tool Vaccum pump, which I actually have used multiple times ;-), THEN you will need to have a shop pump vacuum and test for vacuum retention. At that point, might as well have shop charge it as well to avoid air ingress.
Please let us know how it goes,
George

[retrofast]

Originally Posted by gbalthrop

Questions:
1) Do you know HOW the "Specialist" recharged the system? Did he evacuate and carefully follow the "Vaccum" in the system for at least 30 minutes to see if there was a pressure change? If recharged system loses charge in 10-12 days, that's a SIGNIFICANT leak. A small Change in Vacuum SHOULD have been noted in 30 minutes, BEFORE wasting R-134a & Dye, his time, YOUR MONEY.

2) WHEN & HOW did "Specialist" do "dye test"? What type of "dye" was used? UV (Ultra-Violet) Dye? How long AFTER charging with the dye was the "Test" conducted? Same Visit? Who inspected, and WHAT was inspected?

3) Do you have Blacklight" & UV glasses for seeing the "flourescent" UV Dye (assuming that is what was used)?
https://www.amazon.co.uk/s?k=uv+dye+...s_ts-doa-p_3_6

4) When "Specialist" changed the Condenser, were new O-rings used? HOW MUCH Refrigeration Oil (PAG Oil) was added to system when Condenser was replaced? When they evacuated the system prior to recharge AFTER changing Condenser, did they make sure Vacuum was retained for at least 30 minutes?

5) If "garage" dismisses the oil leak: (a) has anyone there examined the oil deposits? (b) Has anyone there suggested a plausible CAUSE for the oil deposits, other than refrigeration oils (PAG Oil) leaking from Condenser Fitting?

Opinions about A/C systems are like "belly-buttons": EVERYONE has one.
I've maintained my own A/C systems for 50 years. I'm NO Pro, but I understand the basics of the system, have the tools, and take my TIME. A shop can't afford to do the latter -- that's "piddling".

I've NEVER had a leak in an Evaporator Coil. I've had leaks in O-rings, Schrader Valves, & Compressor Seals. I had a leaking hose or two on older systems (with OIL DEPOSITS at the leak site ;-). I've kept vehicles with operating A/C systems until they were 20 or 30 years old (Jag XJ-S & XJ-6/XJ-40). So that is the basis for the following "Opinion".

Most common leak points are O-rings and Schrader valves. Easy to fix. NOT so easy to diagnose. Requires evacuation & Recharge (AFTER testing for 30 minutes or more to see that NO Vacuum is lost). Best way I know is use a UV Dye. Run the system for a week or more. Then inspect for dye leaks with UV glasses & Light. Naked vision in daylight shows NADA. Your location of Refrigeration Oil per your photo is clear evidence of a leak, but if UV Dye was used, you would need a "Blacklight" and Yellow Glasses to see the "Greenish-Yellow" flourescent dye around the leak point.

If you've lost at least TWO (2) full charges of refrigerant in a month or so, you don't really need the dye. Just look for the OIL, like it appears you have already DONE.

Every Line or Hose has a fitting at the end. There is usually an O-ring at every fitting to a component such as the Condenser Inlet & Outlet fittings, Refrigerant Pressure Sensor near Washer filler Tube, Expansion Valve, Evaporator Inlet & Outlet, Compressor lines (High & Low pressure). Also check High & Low Side Schrader Valves at Quick-Connect ports; Compressor shaft seal; & stone damage to FRONT of Condenser coil (the tubes).

NEVER let anyone tell you that you need to have the Evaporator replaced WITHOUT personally observing a pressure test of the Evaporator BEFORE anything but the fittings are removed (test it in place). The car is virtually built around the Evaporator and most everything from the front seats forward has to be removed to get the Evaporator out.

You sound like you know something about A/C systems. Given the time and thought required to identify a leak source, I would suggest investing ~ $50 US or less, and several hours of your time, to try to find the leak yourself. Stuff sold on Amazon UK (or US ;-) is fine for DIY. The Tools needed: One Can of R-134a with UV Dye; Can Tap with Gauge; UV Dye kit (glasses & light). If your system still has SOME pressure > 1 bar, then air & moisture have NOT entered, just R-134a (AND PAG Oil) Lost.

Once you find the leak, you can likely fix it yourself with new O-rings or Schrader Valves, and THEN you'll need to evacuate, Test for Vacuum retention for ~ 1 hour, and recharge. If you do NOT have a vacuum pump (the expensive A/C DIY tool, unless you use a $20 US Air Tool Vaccum pump, which I actually have used multiple times ;-), THEN you will need to have a shop pump vacuum and test for vacuum retention. At that point, might as well have shop charge it as well to avoid air ingress.
Please let us know how it goes,
George

Thanks for that detailed response!

some answers to your questions

1) I have no idea what kinds of tests they did. It's quite a busy place, you leave your car there for a few days and then get a call with an update from someone who may not be close to the work...not ideal but a rock and a hard place situation here for us in Glasgow.

2) They said it was UV dye that they could find no trace of. They recharged the AC once with dye, once it was blowing warm air again I took it back and they searched for the dye. Said they found nothing.

3) I did buy the UV torch and glasses to search for the leak myself but couldn't see anything.. but I don't put much faith in my search.

4) I don't know... I didn't know to ask these things.

5) No. No explanation offered. My fault at this point for not asking for an explanation as they claimed to know it was the condenser at fault.

I am no mechanic but it seems like the Oil deposit should be investigated or addressed before we do anything else now.

I am happy to look into this myself but there is only so much I can do with street parking.

I will now be taking the car back to (B4BMW) the garage that fitted the condenser to ask them to investigate.

However, I think I now need to drive the conversation rather than rely on their expertise as I did before. Should I ask them to replace the hose or just the o-ring? is that hose likely to be an expensive fix?

Cheers

[retrofast]

I took a more recent picture of the pipe/hose covered in oil.

The picture in my original post was PRE condenser change and this is POST condenser change... the plastic part looks broken, unless it is meant to have this groove in it. Can anyone comment on that or perhaps upload a pic of this area on their e92 335i?

Also I have attached pictures of where (I believe) there is an AC pressure switch. From the undisturbed grime it would appear it has not been removed recently so, no one checked there for a leak..

[alpinec1984]

It needs to be truly absolutely dark to see the UV dye effectively, and some lights are better than others. Since my garage has 5 windows I do this after dark only, and use a big UV light that has something like a motorcycle battery for power. It lights up the while stinking area and aim isn't that important.
Amazing how bright the dye glows under this compared to a little UV flashlight with 3 AA cells.

[retrofast]

Originally Posted by alpinec1984

It needs to be truly absolutely dark to see the UV dye effectively, and some lights are better than others. Since my garage has 5 windows I do this after dark only, and use a big UV light that has something like a motorcycle battery for power. It lights up the while stinking area and aim isn't that important.
Amazing how bright the dye glows under this compared to a little UV flashlight with 3 AA cells.

Sadly I don't have anything like that.

I have the kind you describe, with 3 AAA batteries.

I will have another look tonight, weather permitting.

[Serf27]

That’s the power steering cooler line, nothing to do with the AC.
Plastic on the connector looks fine, but the o ring on the line looks like it’s leaking.

[F31B48]

Originally Posted by retrofast

Hi all

Long time viewer first time caller (poster).

I have a 2006 e92 335i and I'm having a hell of a time with my AC. Any advice is welcome.

My AC loses its charge after about 2 weeks and stops blowing cold air gradually.

I had B4BMW, an independent BMW specialist in Glasgow (UK) do a recharge and dye test. They found no trace of the dye anywhere. The concluded it must be the condenser. Had a second opinion from an independent AC specialist and he said the same.

So I had B4BMW replace the condenser...and....same issue.

When charged, it works perfectly for about 10-12 days.

However, there is one hose connected to the condenser that has oil all over it's the end that connects to the condenser, there is no source for the oil from above.

The garage dismissed it as they found no dye there..

Any thoughts on if this could be the issue?

Cheers in advance.

That pipe with the oil on it goes to the power steering oil cooler, not the condenser.

If you can't find any other leaks, then it's most likely the evaporator. The easiest way to inspect it is to remove the heater fan motor and put an endoscope camera up the heater box intake duct.

The other quite common cause of air con leaks is stone damage to the condenser. Have you checked that thoroughly for any signs of stone damage?

[retrofast]

thanks for that! Good to know! right I can stop worrying about that hose, I shall get a new o ring on my next visit.

Condenser has been changed.

One other area, I am told is behind the heat shield where the pressure switch is. I will pull that forward and check with a UV torch.

[eljay]

Originally Posted by EvaBmw

That pipe with the oil on it goes to the power steering oil cooler, not the condenser.

If you can't find any other leaks, then it's most likely the evaporator. The easiest way to inspect it is to remove the heater fan motor and put an endoscope camera up the heater box intake duct.

The other quite common cause of air con leaks is stone damage to the condenser. Have you checked that thoroughly for any signs of stone damage?

How does a leaking evaporator look like? That is, what to look for with an endoscope cam? Will there be physical damage or oil deposits?
I am just curious as I would like to inspect mine at some point.

[F31B48]

Originally Posted by eljay

How does a leaking evaporator look like? That is, what to look for with an endoscope cam? Will there be physical damage or oil deposits?
I am just curious as I would like to inspect mine at some point.

You will see an oily patch around the leak. It's easier to spot if there is green uv dye in the system.

[oVeRdOsE.]

I dont know your place, but here in north america, 90% of leaks are from the
Liquid Line (Condenser to Evaporator) line going in front of the wheel fender. There's a hole in the fender so the dirt/salt/gravel/water get onto it .

next to the last picture you've posted, near the coolant filling hose, remove the heat shield to see the line.

the super long line : part no : 64539151733

I wanted one, none available on rock auto ( huge issue here) when to the scrap yard, 12 e90, all of them got perforated because of the oxidation at the exact same spot.

got a new one, and put some resisto membrane in the fender. fixed

[retrofast]

Originally Posted by oVeRdOsE.

I dont know your place, but here in north america, 90% of leaks are from the
Liquid Line (Condenser to Evaporator) line going in front of the wheel fender. There's a hole in the fender so the dirt/salt/gravel/water get onto it .

next to the last picture you've posted, near the coolant filling hose, remove the heat shield to see the line.

the super long line : part no : 64539151733

I wanted one, none available on rock auto ( huge issue here) when to the scrap yard, 12 e90, all of them got perforated because of the oxidation at the exact same spot.

got a new one, and put some resisto membrane in the fender. fixed

Thanks for this, I was advised this very thing by a local AC expert. I have been too busy to look or go show him the car. I hope it is this as he advised it is a 30min fix!

[retrofast]

Originally Posted by oVeRdOsE.

I dont know your place, but here in north america, 90% of leaks are from the
Liquid Line (Condenser to Evaporator) line going in front of the wheel fender. There's a hole in the fender so the dirt/salt/gravel/water get onto it .

next to the last picture you've posted, near the coolant filling hose, remove the heat shield to see the line.

the super long line : part no : 64539151733

I wanted one, none available on rock auto ( huge issue here) when to the scrap yard, 12 e90, all of them got perforated because of the oxidation at the exact same spot.

got a new one, and put some resisto membrane in the fender. fixed

Using the attached picture of the part you specified. Could you possibly roughly say where this common failure point is?


For example you could say "point 1", "between point 1 and 2" or "to the left of point 1" etc

cheers!

[oVeRdOsE.]

your picture is very a good example, where it's dirty ! between 3-4 , 2-3in of each side on the pressure sensor .


in my case, between the rubber ring and the sensor connector, dirt get stuck there, wont dry, and the pipe get damaged by oxidation.

i know few people get the pipe welded, but its a 50-50 fail-success rate. Aluminum is hard to weld, and this pipe is super thin.

Since its a common issue here, parts are hard to find, dealer is 600$, US part shop is around 250$+150$ shipping. Then you have to install it, flush the system, and refill.

could turn into a 1k$ job.

[TheMidnightNarwhal]

Originally Posted by oVeRdOsE.

your picture is very a good example, where it's dirty ! between 3-4 , 2-3in of each side on the pressure sensor .


in my case, between the rubber ring and the sensor connector, dirt get stuck there, wont dry, and the pipe get damaged by oxidation.

i know few people get the pipe welded, but its a 50-50 fail-success rate. Aluminum is hard to weld, and this pipe is super thin.

Since its a common issue here, parts are hard to find, dealer is 600$, US part shop is around 250$+150$ shipping. Then you have to install it, flush the system, and refill.

could turn into a 1k$ job.

Are you talking about the part being 600$/250$ or job? Because the genuine part on FCP is about 175$ and their aftermarket is 165$.

https://www.fcpeuro.com/products/bmw...mw-64539151734

[retrofast]

Originally Posted by oVeRdOsE.

your picture is very a good example, where it's dirty ! between 3-4 , 2-3in of each side on the pressure sensor .


in my case, between the rubber ring and the sensor connector, dirt get stuck there, wont dry, and the pipe get damaged by oxidation.

i know few people get the pipe welded, but its a 50-50 fail-success rate. Aluminum is hard to weld, and this pipe is super thin.

Since its a common issue here, parts are hard to find, dealer is 600$, US part shop is around 250$+150$ shipping. Then you have to install it, flush the system, and refill.

could turn into a 1k$ job.

In the UK BMW parts are easy to get brand new direct from BMW. Never been an issue.

for reference, this part 2nd hand on ebay with delivery is 50GBP (approx $70)

new - https://www.autodoc.co.uk/car-parts/oem/64539151734
100GBP (approx $140)

AC flush/refil is 60GBP (approx $80).

install - not sure.

[oVeRdOsE.]

Originally Posted by TheMidnightNarwhal

Are you talking about the part being 600$/250$ or job? Because the genuine part on FCP is about 175$ and their aftermarket is 165$.

https://www.fcpeuro.com/products/bmw...mw-64539151734

got the car in 2019, looked for this part in 2019, US-CAD conversion was shit.

600$ was at the dealer.

Now, you can get this part on rockauto 59$ cad.

edit :but still 110$ to ship