BMW E24 AC upgrade(AS OF 2016)

[dcains]

As I understand it PAG is not compatible with R12. This site has more info about oils and it seems to be something about the oil not mixing with the refrigerant so it doesn't get circulated properly: http://www.autoactech.com/issues.htm.

This was interesting to learn:

"100% Compatibility with R12 or R134a and Residual Mineral Oil
Double “end-capped” PAG is compatible with both R12 and R134a and can be used in either application (even with residual oil).

[hakeem43020]

How would one flush the dual AC system with 2 expansion valves?

[hakeem43020]

Just found something that I thought should be worth mentioning. It may be obvious for some people but is still overlooked by many. PLEASE NOTE THAT THE CHARGES INDICATED ON THE STICKER INSIDE THE HOOD OF THE CAR IS CAPACITY THAT SHOULD BE USED WHEN RECHARGING WITH R12.

R12, R134 AND R152 require charging to a different capacity.

The amount of R12 that should be used is normally on the sticker inside the hood
R134 is 80% of the charge of R12
R152 is 62% of the charge of R12

These are the charges that I found online. I'll look into it more later.

WHEN RECHARGING PLEASE USE GAUGES. BUY OR RENT SOME. THEYRE WORTH THE INVESTMENT. DONT USE THOSE SQUEEZE TRIGGER THINGS THAT COME WITH THE CANS. IM SURE SOMEONE HAS POINTED THIS OUT ELSEWHERE BUT ITS WORTH MENTIONING AGAIN.

I now realize that my system has been overcharged for years and is probably why I ended up damaging my AC system in the long term. The low pressure valve on my car has been leaking and this was probably due to overcharging the system and building too much pressure up inside. The leak started small but ended up so bad that I could hear it from inside my car with the AC on. All my refrigerant has leaked out and I never understood how or why.

Quick summary, my car was converted to R134 a while back and who ever did it really half assed it since no hoses were changed and pretty much all parts are still stock. The system was never flushed, just vacuumed and refilled and since then when recharging the system with R134 it was charged to the R12 capacity. 100% instead of 80.

The low pressure valve is located on the voltage regulator so I'll be replacing that, the hoses, Orings, front and rear expansion valve since I have a rear AC. Still not quite sure how to flush the whole system since this has rear AC but I'll figure it out.

I'm a beginner to repairs but I've always been one to value my money and see why repair shops charge what that do and break down the costs. It's expensive to get anything done on these cars hence, my reason for learning. I do have help occasionally but I try to do these on my own since there may not be anyone else to help in the future. So thanks everyone for the help along the way. You all have been really helpful. I'll be documenting the whole process to help many who started as a beginner like me.

Hope everyone can learn from my mistake. Just thought this should be worth mentioning and as usual If I made any errors above please feel free to correct me below.

[88m53453]

remove expansion valve in rear, blow flush from disconnected line on right fender to open line at rear expanion valve. Remove rear evaporator and flush as well . Not impossible, just more work

[hakeem43020]

remove expansion valve in rear, blow flush from disconnected line on right fender to open line at rear expanion valve. Remove rear evaporator and flush as well . Not impossible, just more work

Thanks. Sounds a lot simpler than I imagined. Doesn't sound too hard. Definitely a lot easier than the front .

After being curious about conversion percentages that everyone was using I decided to go out and calculate it for myself.
Mass of
r12 - 120.91 g/mol
R134 - 102.03 g/mol
R152 - 66.05 g/mol

So with all this in mind R12 is the heaviest and R152 is the lightest.
Given the above 84.39%(approx. 84%) of the max capacity should be used when converting to R134 and 54.63%(approx. 54%) when converting to R152. R12 is the most dense and R152 is the least dense. According to the Wikipedia page R152 is said to have been approved for use as an alternative to R134(not sure when or if this part is accurate). As usual someone correct me below if I made an error. I think I got all the info now I just need to find time to get this all done.

[88m53453]

that front expansion valve is the real bear..... To "easily" replace, start at the back, which you will need to do anyway. Rear seats and center console, ,then shifter console and keep going forward. Screws are hidden everywhere, under E brake brushes etc

[slofut]

Just a heads up on the drier situation.
The dual air cars use a drier that is much larger than the single air cars ...to account for the larger volume of charge. Thus the larger price tag. The single air drier will bolt in the dual air cars but provide less capacity for the added charge, also as was mentioned the high pressure switch is a different thread and won't fit. So taking all into account, just buy the bigger drier and be done with it. Speaking from experience...

Also, I'm pretty sure I measured my '88 a while back for a 16x20 condenser using short 90 deg fittings. Haven't done it yet though so fwiw.

And for the side console grilles for the evap fan, has anyone tried the plastic grilles that snap onto the sides of the heater fan under the hood? Maybe let them in from the back side of the console?

BTW... this thread is really getting good now, thanks to everyone who has contributed.

[Mason Jones]

Yeah, this thread should be renamed Endless Summer.

I took a couple of shots of the center console and evaporator box together before I put the box back to get a visual for just how much space is (not) in there. My heater fan side grills seem a little too fragile to put down there.

I'd also like to figure out a way to add an air filter somewhere to keep the evaporator clean.

IMG_1205.jpg

IMG_1208.jpg

[hakeem43020]

Just a heads up on the drier situation.
The dual air cars use a drier that is much larger than the single air cars ...to account for the larger volume of charge. Thus the larger price tag. The single air drier will bolt in the dual air cars but provide less capacity for the added charge, also as was mentioned the high pressure switch is a different thread and won't fit. So taking all into account, just buy the bigger drier and be done with it. Speaking from experience...

Also, I'm pretty sure I measured my '88 a while back for a 16x20 condenser using short 90 deg fittings. Haven't done it yet though so fwiw.

And for the side console grilles for the evap fan, has anyone tried the plastic grilles that snap onto the sides of the heater fan under the hood? Maybe let them in from the back side of the console?

BTW... this thread is really getting good now, thanks to everyone who has contributed.

Thanks for clarifying. Good to know, Ill take your word and pick one up since I have no plans to mess with the AC after this lol. I'll just vacuum it down then get to flushing then pick up the drier after. AFAIK my system hasn't been flushed since I got it and has since been converted to 134 by someone else so it's in need of a flush.

[Mason Jones]

Speaking of air flow, while the evaporator box is out is a good time to check the flappers above the box. Mine were stuck half shut. These are not the same as the vent door controlled by the center slider on the dash that lets in fresh air. These are weighted flaps that are normally closed to block fresh air coming back through the evaporator housing. They open when the AC fan blows.

I’ll try to post some pictures as it’s definitely worth checking while the box is out. I didn't even know these existed until I started feeling around trying to figure out how the vents are hooked together.

- - - Updated - - -

Here you can see the flaps cockeyed the way I found them.

IMG_1260.jpg

And here's how they're supposed to look.

IMG_1261.jpg

I popped the little hinge pins back in place but every time I moved the flaps they fell out again. Ended up being a relatively simple fix. I drilled a tiny hole and attached a tiny clip to hold the hinge pins in place.

Before (you can see the hole I drilled for the screw):
IMG_1265.jpg

After:
IMG_1266.jpg

IMG_1255.jpg

[slofut]

Mason, I can't get the pics to open, get an invalid request error. I would like to see how you pinned the flaps in though. Also, for others that may me digging around in there, the flaps have very tiny plastic pins that are the axle/pivots on each edge. These are very easy to break off and sometimes break off just due to age, so finesse is in order. I have fixed them by gluing on a new axle cut from wire rod (smaller than coat hanger).

[Mason Jones]

Mason, I can't get the pics to open, get an invalid request error. I would like to see how you pinned the flaps in though. Also, for others that may me digging around in there, the flaps have very tiny plastic pins that are the axle/pivots on each edge. These are very easy to break off and sometimes break off just due to age, so finesse is in order. I have fixed them by gluing on a new axle cut from wire rod (smaller than coat hanger).

I uploaded the pics again. Let me know if they're still not showing up and I'll try again.

[slofut]

I uploaded the pics again. Let me know if they're still not showing up and I'll try again.

Got them ok now.

Here's a link for expansion valves. I know there's a generic replacement for the front e24 valve... Rear valve is common.

http://stores.ebay.com/R-Y-A-C-Compr...sub=5188904011

[hakeem43020]

I seem to have figured out my expansion valve problem. The dual AC cars use a different front expansion valve and the earlier ones are not compatible with it, hence why all the ones I ordered didnt fit. As I recall they both are different sizes. Autohauz, Autozone and ebay all recommended the valve for single AC cars and the latter aren't very easy to find. The P/N for the front expansion valve for dual AC cars is 64 50 1 380 658 .

The valve is close to the same price as the drier($110+). Is there a way to simply flush the valve and re-use it or will I have to replace it?

Got them ok now.

Here's a link for expansion valves. I know there's a generic replacement for the front e24 valve... Rear valve is common.

http://stores.ebay.com/R-Y-A-C-Compr...sub=5188904011

[slofut]

I seem to have figured out my expansion valve problem. The dual AC cars use a different front expansion valve and the earlier ones are not compatible with it, hence why all the ones I ordered didnt fit. As I recall they both are different sizes. Autohauz, Autozone and ebay all recommended the valve for single AC cars and the latter aren't very easy to find. The P/N for the front expansion valve for dual AC cars is 64 50 1 380 658 .

The valve is close to the same price as the drier($110+). Is there a way to simply flush the valve and re-use it or will I have to replace it?

I wish I had a used one in hand, I really think there's a possibility it can be matched to a current common valve. It's pretty much exactly like most others that cost 20 bucks! No need it should cost 100!
But, I wouldn't put all that back together unless I knew for 100% FACT that the valve was good!

- - - Updated - - -

I may be wrong...
http://bigcoupe.com/phpBB2/viewtopic.php?t=7578

[hakeem43020]

Thanks.I think this should solve my issue with air seeping through the vents even with the AC off while driving. I normally have to close the ac vents to remedy this. How did you get this off?

Speaking of air flow, while the evaporator box is out is a good time to check the flappers above the box. Mine were stuck half shut. These are not the same as the vent door controlled by the center slider on the dash that lets in fresh air. These are weighted flaps that are normally closed to block fresh air coming back through the evaporator housing. They open when the AC fan blows.

I’ll try to post some pictures as it’s definitely worth checking while the box is out. I didn't even know these existed until I started feeling around trying to figure out how the vents are hooked together.

- - - Updated - - -

Here you can see the flaps cockeyed the way I found them.

IMG_1260.jpg

And here's how they're supposed to look.

IMG_1261.jpg

I popped the little hinge pins back in place but every time I moved the flaps they fell out again. Ended up being a relatively simple fix. I drilled a tiny hole and attached a tiny clip to hold the hinge pins in place.

Before (you can see the hole I drilled for the screw):
IMG_1265.jpg

After:
IMG_1266.jpg

IMG_1255.jpg

Looking back I now remember that the expansion valves for later E24s with dual ac had different coil ends and while the fitting on the expansion valve looks the same they're a size different.

The later e24 expansion valves look something like this:
image.jpeg

Early e24 expansion valves look something like this:
image.jpeg

I found a generic expansion valve on eBay for $20 that looks similar to the one I have. I'll order it, test the fit and report back. If it doesn't fit I'll just clean my valve and reuse it.

I wish I had a used one in hand, I really think there's a possibility it can be matched to a current common valve. It's pretty much exactly like most others that cost 20 bucks! No need it should cost 100!
But, I wouldn't put all that back together unless I knew for 100% FACT that the valve was good!

- - - Updated - - -

I may be wrong...
http://bigcoupe.com/phpBB2/viewtopic.php?t=7578

[Mason Jones]

Thanks.I think this should solve my issue with air seeping through the vents even with the AC off while driving. I normally have to close the ac vents to remedy this. How did you get this off?

Yeah, I had noticed fresh air coming out of the intake vent in front of the ashtray. Now I know why. I'm hoping it will help open up AC air flow to the vents too.

That section with the flappers has 2 metal tabs on the sides that clip on where it attaches to the bottom of the vent section under the dash. Looks like you pull them outward to release. Whatever it clips to had broken off on mine so it basically just took some wiggling to get it off. I have a better photo of it from the top where you may be able to see the metal tabs better. I'll look for it when I get home.

Looking at other photos online I see that there is another type that has latches on the side rather than the tabs I have. Not sure which style you will have. If it's the tabs like I have it looks like you pull them outward to release. Whereas this kind (link below) you just unlatch...
https://www.ecstuning.com/b-genuine-...e/64501376016/

- - - Updated - - -

These flaps just keep fresh air from flowing back through the evaporator. If you have air coming through the vents when the fresh air slider on the dash is closed and AC is off that would mean the "other" flaps (controlled by the slider) that block fresh air from outside are not closing.

- - - Updated - - -

Found a pic that shows the tabs. Not sure if that's helpful at all.

IMG_1259.jpg

Amazing how much has to be in order with the controls/vents/fans/ductwork etc., etc. before the AC system will even have a chance of cooling the air down.

[hakeem43020]

Thanks I'll check it out once I get this apart. If I go around 60 or so I notice air coming through the vents above the radio if the slider is open. If I close the slider the air stops, not sure if thats how these cars are built but it wouldn't surprise me since ac seems to have not been a priority when building these cars.

Yeah, I had noticed fresh air coming out of the intake vent in front of the ashtray. Now I know why. I'm hoping it will help open up AC air flow to the vents too.

That section with the flappers has 2 metal tabs on the sides that clip on where it attaches to the bottom of the vent section under the dash. Looks like you pull them outward to release. Whatever it clips to had broken off on mine so it basically just took some wiggling to get it off. I have a better photo of it from the top where you may be able to see the metal tabs better. I'll look for it when I get home.

Looking at other photos online I see that there is another type that has latches on the side rather than the tabs I have. Not sure which style you will have. If it's the tabs like I have it looks like you pull them outward to release. Whereas this kind (link below) you just unlatch...
https://www.ecstuning.com/b-genuine-...e/64501376016/

- - - Updated - - -

These flaps just keep fresh air from flowing back through the evaporator. If you have air coming through the vents when the fresh air slider on the dash is closed and AC is off that would mean the "other" flaps (controlled by the slider) that block fresh air from outside are not closing.

- - - Updated - - -

Don't know why but that last image isn't showing up for me.

[demetk]

Thanks I'll check it out once I get this apart. If I go around 60 or so I notice air coming through the vents above the radio if the slider is open. If I close the slider the air stops, not sure if thats how these cars are built but it wouldn't surprise me since ac seems to have not been a priority when building these cars.

On the later cars with the electronic fresh air slider, the a/c switch sends a signal to the fresh air flapper controller which activates the stepper motor to close the fresh air flap. This is done automatically for you. On the earlier cars with the cable operated fresh air slider, you need to manually close the fresh air flap so the a/c can work.

[Mason Jones]

Thanks I'll check it out once I get this apart. If I go around 60 or so I notice air coming through the vents above the radio if the slider is open. If I close the slider the air stops, not sure if thats how these cars are built but it wouldn't surprise me since ac seems to have not been a priority when building these cars.

Yes, that sounds right if it's only when the slider is open. I believe on yours it should close automatically when you turn the AC switch on and then the slider does nothing.

Not sure what I'm doing wrong with the images, I uploaded it again.

- - - Updated - - -

On the later cars with the electronic fresh air slider, the a/c switch sends a signal to the fresh air flapper controller which activates the stepper motor to close the fresh air flap. This is done automatically for you. On the earlier cars with the cable operated fresh air slider, you need to manually close the fresh air flap so the a/c can work.

Ha ha, beat me to it! Hey, demetk where are you in CT? I'm originally from Norwalk. I still have family there and around Danbury.

[hakeem43020]

Thanks guys. Good to know that part works. I'll update again when I get my front and rear exp. valves

Yes, that sounds right if it's only when the slider is open. I believe on yours it should close automatically when you turn the AC switch on and then the slider does nothing.

Not sure what I'm doing wrong with the images, I uploaded it again.

- - - Updated - - -



Ha ha, beat me to it! Hey, demetk where are you in CT? I'm originally from Norwalk. I still have family there and around Danbury.

[demetk]

Ha ha, beat me to it! Hey, demetk where are you in CT? I'm originally from Norwalk. I still have family there and around Danbury.

I'm in the tiny little town of Guilford. It's pretty small compared to the Toronto and Montreal of my youth.

[slofut]

Hakeem,
Thanks for trying a couple valves and getting back to us. I do remember when I tackled my '87 AC years back, that the front x valve had the big end and small end positions swapped in comparison with the similar valves I got from the local parts houses. As there wasn't much internet back then I didn't have many sources to choose from. But if you'll notice in your pics, the big/little port orientation on the correct one looks opposite the one for the single ac. Am I correct?
I'm thinking I'll check some other dual air vehicles and see what they use.

This looks promising...

http://www.ebay.com/itm/A-C-Expansio...-/331846657765

Has 134a stamp, makes me wonder what parameters are different between gasses. I'm pretty sure I'm going with r152 when I address my ac.

[hakeem43020]

Hakeem,
Thanks for trying a couple valves and getting back to us. I do remember when I tackled my '87 AC years back, that the front x valve had the big end and small end positions swapped in comparison with the similar valves I got from the local parts houses. As there wasn't much internet back then I didn't have many sources to choose from. But if you'll notice in your pics, the big/little port orientation on the correct one looks opposite the one for the single ac. Am I correct?
I'm thinking I'll check some other dual air vehicles and see what they use.

This looks promising...

http://www.ebay.com/itm/A-C-Expansio...-/331846657765

Has 134a stamp, makes me wonder what parameters are different between gasses. I'm pretty sure I'm going with r152 when I address my ac.

No problem and Its possible. I really Didn't notice that until you pointed it out. I still have the old valves I ordered somewhere laying around, I'll be sure to try them and report back.

Found this image a while back. The compressor diagram below should come in handy, it says 85-86 635csi, not sure if it relates to the older/newer models but I'm guessing it'd be somewhat similar if not.



Also found some instructions.

Hopefully someone will find these useful

[tonym427]

How many ounces of refrigerant is required to refill? Also what did you use for the flush