A/C wizards! Need help with Denso system, receiver drier switches

[boy412]

My '88 'vert has a Denso compressor and the system was converted to R134a at some point prior to my ownership. I am in the midst of getting the system operational again and am struggling with finding information and part numbers for many of the components of this system.

RealOEM part diagrams show parts that look NOTHING like what is on my car. ECS Tuning and Pelican also do not list parts that look like they belong in my car. The Denso compressor is very different from the Bosch and Seiko units. Just take a look at how the refrigerant lines connect:



The drive belt for this compressor is also not the same as the part listed for my car. THIS compressor takes a 13x825 belt (p/n 64551722990), as opposed to the 13x810 belt that came with the "kit" I bought from Pelican.

The receiver drier I bought is also not the same as the one that is currently on the car, which has two pressure switches incorporated into it. Here's a photo of the old one next to the new one. As you can see there are no bungs on the new unit for two switches:


Does this mean I have to buy the $$$$ "Genuine BMW" part (64538391025)? This is literally 6X the price of the OEM Behr part. I also see another part listed @ Pelican (64531466051) but their photo does not show this side of the drier.

I'd like to track down a diagram and some part numbers for everything, but my immediate concern is finding the correct O-rings for the compressor-side connections (there are four and the size does not correlate to anything I've found in the parts catalog) and the hex socket cap screws that hold these connections onto the compressor. I started to strip one when I was removing them and I'd like to just replace all four with new fasteners. I could just figure out the size and order them elsewhere but it would be a lot simpler if I could just find the BMW part number.



So...little help please? I don't know why this car's climate control system is so different from the standard E30 spec but its making this project a lot more difficult than it needs to be!

[nrubenstein]

You bridge the connections on the sensor you can't connect (genuine BMW will be like this too).

The compressor should have adapter blocks on it. If they are missing, it's probably easier to just get another compressor.

[boy412]

The "adapter blocks" as you refer to them are actually still attached to the refrigerant lines. So that's not an issue.

:)

I think I've found the correct O-rings. 4 Seasons p/n 24613. We'll see whats what once they arrive.

Interesting about that switch. Really just bridge the connector? I thought it was weird that the drier I pulled off the car has TWO switches on it. You can still buy both of those parts but none of the receivers I've seen are provisioned for them both.

I see you're in DC as well! Howdy neighbor! :)

[boy412]

So I'm learning a bit more about this. Looks like later model E30's moved to a single pressure switch instead of the high/low switches on the earlier cars. If I am correct it looks like you need to replace the two switches with a single switch that handles both low and high pressure. This switch has a slightly different connector so along with the switch itself (64538390971) you also need this new connector (61131378400).

This would explain why all the new receiver driers I've seen only have the provision for a single sensor, although SOME of the aftermarket driers (iRO brand for instance) look like they still have provisions for both.

[cabriodster87]

The Detailed E30 R-134a Conversion Thread/DIY is an excellent place to find tons of info.

[jeffnhiscars]

I just received 2 brand new Behr dryers and both came w o rings and have 3 plugs that can be removed to install switches. I got them from autohausaz az and think they were about $14@.
Note they are vacuum sealed to keep humidity out so best not to bust the seal til you are ready to install them...and yes..all quality parts are made in China :-)

[boy412]

The Detailed E30 R-134a Conversion Thread/DIY is an excellent place to find tons of info.

Oh you mean THIS one? I had found that a year ago when I first got the car. Lots of good info for sure! Although I don't recall seeing anything in there about the two switch vs one switch thing. Admittedly I did not read all 7 pages though.

I just received 2 brand new Behr dryers and both came w o rings and have 3 plugs that can be removed to install switches. I got them from autohausaz az and think they were about $14@.
Note they are vacuum sealed to keep humidity out so best not to bust the seal til you are ready to install them...and yes..all quality parts are made in China :-)

Interesting. Mine came with O-rings but doesn't have as many bungs for switches as the ones you got.

I already have the drier so I'll just get a new (single) switch and updated connector. I was going to buy new switches anyway.

Any advantage to running the two switches as opposed to a single one? I will assume not since all the later model cars went to a one switch design.

EDIT: Jeff...just read through your thread and was wondering why you didn't just convert to a one switch system? That was an awesome writeup by the way. :up:

[jeffnhiscars]

EDIT: Jeff...just read through your thread and was wondering why you didn't just convert to a one switch system? That was an awesome writeup by the way. :up:

I was already wired for 2 switches so I replaced the low pressure switch and reused the high pressure switch as it was back ordered everywhere.

[Tom.]

I've ran into a lot of the same issues as you, and I've come to the conclusion that someone swapped in early model A/C components to my late model e30. The late model compressors have some sort of elbow built in that one of the lines connects to. The early model compressor doesn't , so I had a really hard time getting the stock late model line to mate up to the compressor. I have no idea if this is why you're asking about orings, but that stage had me confused for all of last summer before I realized it wasn't the stock compressor. (I think?)
I also have a useless 13x810 belt and I also have a strange assortment of pressure switches.

I'm not really 100% though, because all of this I've just gathered from staring at RealOEM or looking at junkyards.

[jeffnhiscars]

I believe my 87 sedan has that same compressors would some pics help ?

[boy412]

Pics ALWAYS help. :)

I think I've got all the information I need for my project, but if you wanted to post some pictures I'm sure others would find that helpful. My major concern was not finding anything in RealOEM that corresponded to the setup on my car. Just finding the correct sized O-rings was a challenge (hopefully I've ordered the correct ones!).

Jeff...this was the switch that was out of stock when you replaced your drier, yes? And am I correct in assuming that this handles both low and high pressure switching?

[jeffnhiscars]

That switch doesnt look familiar but I was not looking to convert to a single hi/lo switch. I started with 2 and finished up that way.

I believe this is a denso so hope the pic helps

[boy412]

Parts started arriving today...and I'm still unsure about these two different types of switch setups. I got one of these:



...along with one of these:



So now the problem is the connectors are obviously quite different. Once I jumper one of the connectors like shown here (photo credit goes to Pennyw1se on BimmerForums).



...I'm left with the connector for THIS switch:



I'm starting to think I'm chasing my tail around by trying to work with the new drier I bought. Might be easier to just stick with a two switch setup! Although I am curious how other people convert to a single switch setup.

[jd_e30]

Subscribed. I can snap some pics if it helps....

[boy412]

Pics of what? :D

Nice coupe you have there jd_e30!