The Detailed E30 R-134a Conversion Thread/DIY

[808ETA]

Thank you to glucklich21 for the original write up and Jeffinhiscars and everyone for the updates.

I have an 84 ETA. When I bought my car 2.5 years ago the A/C wasn’t cold. I took it to an A/C repair, and they changed the fittings and filled the car up with R134. They A/C was cold for about 9 months and then it started to get warm again. I usually had the system recharged every 9 months. The last time I had it recharged they put dye in the system to find the leak and it got warm after less than 6 months. When I took it in, they could not find a leak anywhere. We didn’t look at the evaporator and they said the leak could be there.

I was initially going to just change the O-rings and dryer however my good friend Victell had an extra evaporator and John (ForcedFireBird) gave me some expert advice. I said what the hell I might as well do everything while the system is evacuated. I put in a new evaporator, R134A expansion valve, parallel flow condenser and flushed the lines. I’m in Hawaii and it’s usually 75-85 degrees and rarely breaks 90 so I decided not to go with a Spal fan.

I bought a new pressure switch for the dryer however I was wondering if I could use my original low and high pressure switches. The new switch valve pin doesn't seem long enough, and I would prefer to not have to cut/splice any wiring.

[cory58]

Thanks for the heads up

Looks like Nissens' quality control is not great. Per post #602 above, my original fan bolted up to the new condenser with almost no hassle.

Cory

[digger]

Thanks for the heads up

[mjweimer]

Anyone tried the Nissens parallel flow condensor?

Yes. The core seems very nice but the mounting tabs for the fan seem to be haphazardly placed on the frame. I had to relocate two of the mounts to get the fan to fit properly.

Not a big deal but it takes some time to drill the rivets and carefully re-drill the holes. I have heard stories of others receiving the condenser with the top and bottom mounts flipped around backwards.

[digger]

Anyone tried the Nissens parallel flow condensor?

[mlytle]

follow up...screw finesse...just yank the %^&*( thing out and accept that the fins are going to get bent. interesting that the new one is slightly shorter than the original so it should go back in easier.

[mlytle]

great info in this thread. going through the conversion process on my 88 M3. hit a snag with evaporator. it does not just slide out to the right. top corner of evap hits metal ridge in body. rather not take entire center stack apart...is there some trick to getting the thing to clear out of there?

see yellow circle in pic below. misses by about a half inch. argh...

[cory58]

Thanks to the great info here, elsewhere on the internet and in Rob Siegel's "Just Needs a Recharge," I finally updated the AC system in my Touring. Many thanks to the OP of this thread and others who have posted.

My Touring had functional and surprisingly cold factory AC when I bough it in 2015. A few years later, an old R12 o-ring in one of the dryer connections failed. I replaced the o-ring and dryer then evacuated/refilled the system. A short time later the front seal on the Sieko compressor failed. I decided to update the system and started acquiring parts. The system was working great prior to the compressor seal failure, so I decided to not touch anything under the dash.

Here are the parts I replaced.

Sieko compressor rebuilt by by Discount Auto AC, Daytona Beach, FL ($170 plus shipping one way)
New Nissens' parallel flow condenser
All new OE under-hood hoses (4)
New receiver/dryer

The project was easy, the most difficult part being removing the front valance. I'd never done that before and it took a while to find all the mounting bolts. The other frustrating part was finding that my Harbor Freight vacuum pump had failed. I bought it when the o-ring failed a few years ago and only used it once. I charged the system with a little over one small can of 134a. The ambient temp was about 57 here. When the vent temp got down to 38, the compressor would cycle off, the vent temp would go up to 40 and the compressor would cycle back on. I think this means the evap temp sensor is working. At that point I decided to stop charging until a warmer day. Here are some pics.

Freshly rebuilt compressor. Discount Auto AC was great to work with and their rebuild service was fast, even over Christmas. They gave me the option of painting the compressor or just cleaning it (to maintain the factory look).

IMG_4226 by cory58f5, on Flickr

New hoses/lines. Note the updated hard line along the fender that clears the hood hinge. I could only find this part spec'd for a cabrio. I bought it anyway because I knew it would fit other models.

IMG_4228 by cory58f5, on Flickr

New Nissens' condenser. I've read that others had problems with the mounting brackets but they were fine. The angle of the top left fan bracket was off so I had to bend it a little.

IMG_4229 by cory58f5, on Flickr

Cory

[cory58]

Think I just answered my own questions. Found this info on an automotive AC forum.

"Gas is always on top of the can, so holding the can upright will charge gas, upside down, liquid."
"Simply turn the cylinder or can upside down to charge as a liquid or leave it upright to charge as a gas."
"But never charge as a liquid if the low pressure port is on or near the compressor because it can slug the compressor as they are not made to compress a liquid, only a gas."

[cory58]

Just received my rebuilt compressor back and this notice was in the box. Not sure what "Liquid Charge" means. Is that warning something I need to worry about? My understanding is that the refrigerant becomes a gas when it flows from the can through the gauges and into the system. Is that not correct? Are the refrigerant cans I buy from the auto parts store actually feeding the refrigerant in as a liquid? When I turn them sideways I do see a liquid in the site glass of the gauges, but I thought that was ok as long as you continue to rotate the can and not leave it sideways. All advice will be appreciated.

Thanks, Cory.

compressor rebuild warning by cory58f5, on Flickr

[jeffnhiscars]

It's the one change that will improve your idle performance since there's just not enough air flow at idle to dissipate enough heat. Booth high and low circuits use the same .5 wiring so that's fine but you'll want to use the fuse rated for high on the low circuit since it's now drawing more.

the SPAL is fine especially if you're using a 16. I run a 14 w curved blades

[Caperix]

I've got it wired to run 2 speed right now. I have jumped the high speed relay & tested & did not notice any improvement. Is the spal not efficient at lower speeds, or do you suggest wiring for high only just to get max air flow?

[jeffnhiscars]

That bracket looks great, I wish I had known about it a few years ago when I replaced the Seiko compressor on my 91. Used a "new" rock auto one so I could keep the old one to look into rebuilding. It works good when moving but at idle in 90 degree weather the temp creeps up even with a parallel flow condenser & 16" spal pushed.

Did you jump the resistor so the fan always runs on high ? The SPAL is fairly quiet so the sound shouldn't change much...just be sure to update the low speed fuse

[Caperix]

That bracket looks great, I wish I had known about it a few years ago when I replaced the Seiko compressor on my 91. Used a "new" rock auto one so I could keep the old one to look into rebuilding. It works good when moving but at idle in 90 degree weather the temp creeps up even with a parallel flow condenser & 16" spal pushed.

[cory58]

- LC Wylie M20 compressor bracket (facebook)

Wow - timing is everything! Finally broke down and sent out my Seiko for rebuild LAST WEEK, and now I find out LC Wylie is making M20 conversion brackets. I've always known about their M30 brackets but hadn't checked the FB page in a couple of years. Ugh!

Cory