E30 + R134 = not impressed

[Falconer]

Bumping this thread to see if I can get some help.

I opened up the A/C system to change out the receiver/dryer, change the expansion valve along with the o-rings and a few of lines that looked a bit corroded.

I filled the system up with a can of this: http://www.canadiantire.ca/AST/brows....jsp?locale=en

R12a. I put in one can (6oz's), and the instructions said to not allow the pressure to exceed 38psi. Should I be filling the e30's system with this stuff by weight or just by the pressure? The A/C doesn't seem to want to blow really cold at idle/city speeds.

[nrubenstein]

just replaced my low side hose after it burst and shot oil all over my hot header....thought my engine was on fire!! new line was already r134a ready (no converters needed), but also cost way more than the r12 line cost me just a few years ago.

anyways, i put in 2lbs to start, but pulled that back to ~1.9. at idle in the shop today with the hood open, blower on 4, and recirc off, i was seeing 46* at the center vents. roughly a 30* drop from ambient. a few weeks ago when i charged the system w/ a little less, i was seeing slightly higher temps at highway speed. i'll have to see how it does when highway cruising w/ recirc on.

don't know if i'll see the same vent temps that you are nick, but i sure hope so!

Today, driving around, I'm staying in the 30s with recirc off. Of course, I'm also between fan speed 1 and 2 since it's so nice out. (Tinted the glass on Friday, so no windows down.) K's car blows about 2 degrees warmer than mine. I don't know if that's a random variance or compressor difference as my car *does* have an E36 compressor.

[jht3]

just replaced my low side hose after it burst and shot oil all over my hot header....thought my engine was on fire!! new line was already r134a ready (no converters needed), but also cost way more than the r12 line cost me just a few years ago.

anyways, i put in 2lbs to start, but pulled that back to ~1.9. at idle in the shop today with the hood open, blower on 4, and recirc off, i was seeing 46* at the center vents. roughly a 30* drop from ambient. a few weeks ago when i charged the system w/ a little less, i was seeing slightly higher temps at highway speed. i'll have to see how it does when highway cruising w/ recirc on.

don't know if i'll see the same vent temps that you are nick, but i sure hope so!

[immajackuup]

my r12 a/c sucks against texas heat:(

[jw 325ic]

just did the r134 conversion a couple of weeks ago...in texas with no complaints. it's cold and thats what matters. if i hit the recirculate button it gets even colder to where i have to turn it down a peg...

[BMWManiac]

I have never been in an e30 with working AC, but I will put out there that BMW AC is nothing like US car AC by any standards. I have always thought my wifes E46 since new sucked compared to my old Chevy truck. have it charged and deal with it I guess....

The AC in my Z4M and in my e36 M3 is awesome.....I have no complaints.

[nrubenstein]

The only time the sight glass is untrustworthy is when you've got contaminants in the system.

I understand fully what you guys are saying, you want a definitive fill weight. If BMW's got one, use it. I must say though that I've successfully retrofitted a lot of different equipment with a lot of different gasses- 502>408a, 502>402a, r12>414b, r12>401b... all using the sight glass. I've had my scale batteries die in the middle of a charge, aaaaaaaaahhhhhhhhh what ever will I do?? Use the sight glass. It is as easy and reliable as watching the digits on a scale.

Yes, but there is a key difference between you and me when it comes to HVAC: Competence. :)

[Ryann]

the sight glass is not a reliable way to fill unless you are starting with a completely fresh or fairly young system using the original gas.

The only time the sight glass is untrustworthy is when you've got contaminants in the system.

I understand fully what you guys are saying, you want a definitive fill weight. If BMW's got one, use it. I must say though that I've successfully retrofitted a lot of different equipment with a lot of different gasses- 502>408a, 502>402a, r12>414b, r12>401b... all using the sight glass. I've had my scale batteries die in the middle of a charge, aaaaaaaaahhhhhhhhh what ever will I do?? Use the sight glass. It is as easy and reliable as watching the digits on a scale.

[nrubenstein]

^ is that on r134?

Yes.

I must emphasize that at those temperature and at 60-70% humidity, it is critical to use recirc to get acceptable performance, though.

Not that I'm complaining.

[LJ851]

^ is that on r134?

[nrubenstein]

Oh yes, and here is why I advocate filling by weight:

On the highway, fan speed 4:


After idling for 5 minutes, fan speed 4:


Note that you DO need to cheat and use recirc to get this sort of performance. Sucking in really hot, humid outside air will hurt performance a lot.

[bloodshot-e30]

My E46es have always had perfectly good a/c, but the GM systems seem to be pretty thoroughly overspecced in my experience.

meh im not real sure on american cars. all i work on is german cars and i can usually get any audi, mercedes, bmw, porsche, VW,etc etc down below 34* from vents.the jetta i finished today was literally too cold and i had to turn it off while test driving it lol

[nrubenstein]

im gonna dissagree... i kno how to work on AC and i got an E46 to blow out 27* from the center vents and 31 on the out side vents at full blast ;)

just gotta get the pressures on high and low correct ;)

My E46es have always had perfectly good a/c, but the GM systems seem to be pretty thoroughly overspecced in my experience.

[bloodshot-e30]

I have never been in an e30 with working AC, but I will put out there that BMW AC is nothing like US car AC by any standards. I have always thought my wifes E46 since new sucked compared to my old Chevy truck. have it charged and deal with it I guess....

im gonna dissagree... i kno how to work on AC and i got an E46 to blow out 27* from the center vents and 31 on the out side vents at full blast ;)

just gotta get the pressures on high and low correct ;)

[csermonet47]

Fill that sombitch till it won't fill no more.

That is what I have been doing anyways. Replaced my A/C belt today and it blows pretty cold and it was 90 something out.