The Detailed E30 R-134a Conversion Thread/DIY

[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]

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.

[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?

[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]

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.

[bignslow]

I am in the process of converting mine over. Anyone know what the high side R134a conversion fitting needs to be used? I was under the assumption that all cars were the same but out of the 2 conversion fittings that I got only the low side fits. The high side is different.

[S.J.1981]

Thank you for this detailed write up, despite it being a 2012 thread.

My R12 system is empty, and my local Bosch service center is the only one, who is willing to convert to R134a for me. He gave me a quotation between €2.000 and 2.500, which does NOT include a new compressor or condenser fan (if needed).

Since the system is empty, i was interested to see, from the hardware side, what is required, thankfully you covered all of this.

You gave me the confidence to tackle this myself, then let the professionals correctly charge the system.

[jwest11]

Looks like this thread is still active so any help is appreciated. I just got to the point of tearing everything apart under my dash and would like to know if anyone thinks my evaporator is good or not. I'm trying am trying to get this done asap. Thank you!

Links to photos since it wont let me upload for some reason...

https://drive.google.com/open?id=1eL1QD7IL4cMVCnQxq_Ti_yrwTX4hyrcm

https://drive.google.com/open?id=1VBSBIUuEugk1L5opGNISmwFe9VUwO9Cg

[S.J.1981]

It may look "bad" but honestly only a professional with a leak detector machine can tell.

[330SMG]

Looks like this thread is still active so any help is appreciated. I just got to the point of tearing everything apart under my dash and would like to know if anyone thinks my evaporator is good or not. I'm trying am trying to get this done asap. Thank you!

Links to photos since it wont let me upload for some reason...

https://drive.google.com/open?id=1eL1QD7IL4cMVCnQxq_Ti_yrwTX4hyrcm

https://drive.google.com/open?id=1VB...ISmwFe9VUwO9Cg

If it is the original one just change it. Mine blew out late last year. They are not that expensive and you might as well just rebuild the whole system to ensure longevity.

[S.J.1981]

id like to ask, before ordering all the parts required. Is there any way i can actually test the compressor? in terms of proper function instead of just if the clutch engages or not?

I know the clutch engages, but the system is empty. Id like to safely test the compressor first. Any suggestions?

Update: Got a 510g can of R12 "replacement" gas, filled the system (i know there is a leak at the condenser and the dryer/receiver is the original 1990 one and rusted out), but i wanted to see if the system can still cool.

So the fan came on, clutch kicked in, and as long as the car was moving, there was 1/2 decent cooling from the vents. So i know the compressor and condenser fan work. I shall be getting a vacuum pump, new parallel flow condenser (Nissens brand), new receiver dryer (R134a) with correct pressure switch, new evap (R134a) and maybe even a new evap (still undecided if i should clean out the original or get a new one).

If someone can be specific with the o-rings linked on page 1, which seal goes where (realoem is not helpful) id appreciate that.

[325e '87]

Ok, i have read everything i can find and am doing the upgrade to the parallel flow condenser this week.

I went and got a vacuum pump and the harbor freight a/c service manifold (red, blue gauges and yellow fill/evac line).

My question is, when I go to refill with 134a do I just screw the yellow hose fitting onto the bottle of 134a? I don’t see if there is a prong in the center that will break that seal. The end of the yellow hose that is supposed to go on the manifold looks like it has some kind of Schroeder valve, or is that the prong that is supposed to break the seal on the refrigerant bottle?

Thanks

[The Dark Side of Will]

You'll need a "can tap"

The T-handle drives a spike which punctures the can seal.

https://www.amazon.com/Interdynamics.../dp/B000CO7Q6U

https://www.autozone.com/test-scan-a...n-tap/944974_0

[325e '87]

Thank You!! Ordered.

[325e '87]

Ok, I replace the condenser and the dryer, resealed and held 30” vacuum for about 12 hours.

I cant get my system to draw in more than about. 10oz. Of refrigerant. I’m getting kind of angry and considering pumping it back down to vacuum and trying again.

My pressures are nearly factory, 40psi low, hovering around 200psi high. I know the pressures need to go up from where they are but Ive been running my engine for an hour now, revving sometimes. When I rev it my low side drops to around 20psi, high side drops a little.