The Detailed E30 R-134a Conversion Thread/DIY

[doctorx]

When I did the truck conversion, the ac hadn't worked in years. So there was no freon. Otherwise i would have had it vacuumed. My e30 does cool a little so i am guess there is still freon in there and want to do the responsible thing and not release it to atmosphere on purpose.

[The Dark Side of Will]

There's zero penalty for you as a private citizen to just blow out your entire freon charge into the atmosphere. Be careful, as it will carry oil with it. You'll get a lot of refrigerant oil out with the freon unless you blow it down very slowly.

I say this because HVAC work by a certified shop tends to be grossly overpriced, probably because the required license limits the number of these shops that can perform the service.

When R12 comes in contact with moisture, it becomes corrosive. This is why R12 systems need to be pulled down to a hard vacuum for several hours before being charged. The vacuum causes any moisture in the system to flash off and come out to the materials it's been absorbed into and be removed from the system.

R134 and R12 drop-in replacements are not nearly so sensitive to moisture, so the need to have excellent vacuum prep of the system prior to charging is not as great and basically limited to removing enough gas from the system that the remnant does not displace a noticeable amount of refrigerant.

That doesn't answer your question, but probably useful background info.

[doctorx]

just thought i would put my 2 cents in. My 92 GMC Sonoma was no longer cooling. It had r12 in it (funny since i read it was last used in 91). It no longer had any freon left so i used Interdynamics EZ Chill Recharge & Retrofit Kit and it has been great ever since. This has been almost 4 years now. I have not had to add any more since. I also converted from mechanical fan to electric fan 2 years ago.

My 87 325i is not that cool... so considering doing the same. How much is it usually to vacuum out the exiting freon?

[jeffnhiscars]

I recently took the front trim apart to replace the front apron. While there, I decided to replace the original accessory fan with a 14 inch 2400 CFM that was recommended in the original post.

My question, should I bypass the fan resistor so when it comes on with the AC it's at max power? Or will that somehow screw up the high temp circuit that forces the fan to max power?

The high temp circuit will work fine if the AC is off. Just bump your low speed fuse to match the high speed fuse. The wires are ide tidal so it will handle the load.

[tomstin]

I recently took the front trim apart to replace the front apron. While there, I decided to replace the original accessory fan with a 14 inch 2400 CFM that was recommended in the original post.

My question, should I bypass the fan resistor so when it comes on with the AC it's at max power? Or will that somehow screw up the high temp circuit that forces the fan to max power?

[jeffnhiscars]

What is the material around the expansion valve? mine is no longer reusable!

Any AC supply house will sell you a small roll of insulating tape. The original stuff appears to be a combination of butyl and some kind of foam bead. Either way it's just an insulator to limit condensation at the expansion valve.

[changyeamoon]

What is the material around the expansion valve? mine is no longer reusable!

[PDXPeter]

Did we ever figure out if other compressors would bolt on with little or no modification? My compressor crapped out so I need to get a new one. Im not adventurous enough to go all electric. If not Ill probably go on a hunt in the junk yard and see what I can find.

[Originale30]

A few thoughts. My HVAC box has three drains. One on each side then one in the middle near the ash tray.



For the leaking near the expansion valve, find some insulated tape, when that area is dry, and seal it all up.



I’ve rebuild my system and at idle the performance is poor. With my 325E and the low gear I’ve started staying in a gear lower than normal to keep the RPMs up.

I have a similar issue, all a/c components have been replaced with new r134a except the evaporator and the a/c compressor, all seals in the system have been updated with r134a seals including the a/c compressor, but my idle a/c performance is poor.... weak compressor? Any ideas? Thanks


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[jeffnhiscars]

A couple more notes.

The insulated tape isn't to seal but rather is to limit condensation at the expansion valve and connections.

Any AC will under perform at idle given the lack of air flow to help dissipate heat. My understanding of a swap is you delete the mechanical fan which would actually have a negative effect on air flow at idle.

There is no magic bullet. Clean tight system, evac to 500 microns, charge and go.

[Caperix]

A few thoughts. My HVAC box has three drains. One on each side then one in the middle near the ash tray.

For the leaking near the expansion valve, find some insulated tape, when that area is dry, and seal it all up.

I’ve rebuild my system and at idle the performance is poor. With my 325E and the low gear I’ve started staying in a gear lower than normal to keep the RPMs up.

I'll have to look into that 3rd drain & pick up some insulation tape. I guess the poor idle performance is just one more reason to look into a 24 valve swap.

[tomstin]

I blew air through both drains from the bottom, the pass side is pita to get at.

One other question on converting to r134a, is it normal for them to have poor performance at idle?

A few thoughts. My HVAC box has three drains. One on each side then one in the middle near the ash tray.

For the leaking near the expansion valve, find some insulated tape, when that area is dry, and seal it all up.

I’ve rebuild my system and at idle the performance is poor. With my 325E and the low gear I’ve started staying in a gear lower than normal to keep the RPMs up.

[Caperix]

That could be a cause but don't rule out a clogged drain

I blew air through both drains from the bottom, the pass side is pita to get at. Both drains do have water draining out of them, when I pulled back the corner of the center console it looked to be running down the side of the box from further up.
I do not know how long the a/c did not work in this car, I feel like it was probably a large number of years. I did not see anything obvious when I replaced the expansion valve, but the insulation was falling apart.
One other question on converting to r134a, is it normal for them to have poor performance at idle? I have replaced every part but the evaporator & have a spal 16" pusher installed. With some rpm it works great, but at idle in 90 degree heat with 90% humidity its a little warm. I need to hook some gauges to it and see what my pressures look like. I filled with 2 lbs but I don't know if the parallel flow condenser increases capacity.

[jeffnhiscars]

Does that help with moisture as well? I am getting water running down the pass side of my heater box with the AC on. I need to pull the glove box & find the source, but I suspect it is the expansion valve or lines.

That could be a cause but don't rule out a clogged drain

[Caperix]

I bought a roll of 2" insulating foam tape from an AC supply house.

Does that help with moisture as well? I am getting water running down the pass side of my heater box with the AC on. I need to pull the glove box & find the source, but I suspect it is the expansion valve or lines.