I can't figue out if this A/C compressor is a DA6 or an HR6
Can anyone help me identify it please?



I have a few more basic, (dumb), A/C questions that I'll post here in a little while...
Any expert help will be greatly appreciated, especially when I'm cruising around all comfy and cool this summer.

I have searched everywhere to find the red and white switches on the back end of this compressor.
All I am able to find are replacement switches that are 2 terminal rather than the single terminal ones shown here.
Where can I find the correct switches?



The plastic "mushroom" head on the white switch crumbled apart when I removed it from the compressor.
I inadvertantly crushed the round terminal post on the red switch, so I crimped spade connectors on each one in the event I can't find new ones and have to re-use them.
(I'll modify the harness connectors and put small rubber tubing over the connections to "weatherproof" them until I can do it properly)

[This message has been edited by randye (edited 03-08-2010).]

It looks like a V5 compressor. Is your car a 4-cylinder?

quote Originally posted by randye: I can't figue out if this A/C compressor is a DA6 or an HR6

They are virtually identical externally. The only significant difference I'm aware of is that the DA6 used an aluminum cylinder block while the HR6 cylinder block is ferrous. Have you tried a magnet on the cylinder block?

quote Where can I find the correct switches?

The two-terminal switches are just about all you can find these days. Just buy a mating connector, then splice one terminal into the existing harness and connect the other terminal to ground.

quote Does this [wire screen] absolutely need to be reinstalled?

Yes ... unless you don't mind water droplets spitting from the A/C vents most of the time. The screen is a simple way of catching any condensate that blows out of the evaporator.

quote Originally posted by TopNotch: It looks like a V5 compressor. Is your car a 4-cylinder?

I think it is a V5 also. If it is you can get the switches at NAPA, the connectors also were listed there if you need them. The red is the high presssure switch, and the white one is low pressure.

I'm fairly certain this isn't a V5 compressor.
To the best of my knowledge, and what I've researched, the V5 compressor has a pressure relief valve on the *side* of the case.
This one does not.
It is the original compressor out of my 87 GT. Both the DA6 and HR6 compressors were supposedly used in 87 GTs
I'm concerned about identifying it, as I am converting to 134a and I understand that the DA6 is a poor choice vs the HR6 for 134a, as the latter is better suited to the higher pressures with 134a refrigerant.
The compressor in the photo has an aluminum housing, but notably does not bear the "HR6" designation anywhere on it's label.
This photo was posted by someone else here on PFF and clearly shows the "HR6" designation on the compressor label:

I also note the different model number on my compressor vs. the one pictured above.

[This message has been edited by randye (edited 03-08-2010).]

A google search result:

DA6; 1st Design; OE #1131469; SINGLE GROOVE CLUTCH

This info is not verified but I would think it makes sense and it lends some credibility to the possibility that your compressor is in fact a DA6 and therefore undesirable.

When I first worked on my 86 A/C it must have already had a compressor change as it said "HR6" on the label just as the photo above does.

If it were mine, I would use your compressor as a core if it can be used for that. I bought my replacement high and low pressure switches from both AutoZone and Checker auto parts. good luck.
Charlie

[This message has been edited by cptsnoopy (edited 03-09-2010).]

quote Originally posted by Marvin McInnis: Yes ... unless you don't mind water droplets spitting from the A/C vents most of the time. The screen is a simple way of catching any condensate that blows out of the evaporator.

Thank You Marvin.

It looks like I may have to learn more about the available switches. There appear to be a plethora of them to choose from, in various color codes.
I'll need to determine which ones I need.
The 2 terminal problem seems easy enough to resolve.

Regarding my question about the "water trap" screen:
I understand the intent of the "water trap" and not to be argumentative, but;
As I have the front blower housing removed I was able to inspect, (and clean), some of the HVAC internal housing, at least around the mixer door and into the immediate duct behind the evaporator. What I noted is that the air blows through the heat exchanger and directly onto a flat inner wall of the housing before making at least (2) 90 degree turns inside the housing before even being directed to the vent ductwork. There is a small depression or "trough" in the floor of the HVAC housing that collects condensate and flows it to the drain tube. This "trough" extends well past the evaporator. My concern with reinstalling the wire screen was predicated on the fact that, upon disassembly, I discovered one corner of it bent where it was making contact with the mixer door which in turn had prevented the mixer door from fully closing off the heater core. (One of the reasons I wasn't previously able to get full A/C cooling and had warmer than ambient air when in "Vent" mode.)
I'm not certain, but I believe this is a design error by GM, as the mixer door edge swings *very* close to the evaporator face and looks like it actually rubs across the wire screen when it is in place, (at least in my 87 GT).

I was able to readjust the cable clip on the mixer door actuator arm and get the door to again fully close off the heater core. (as shown above)
My worry is that reinstalling the screen will again cause the same problem with the mixer door.

EDIT TO ADD:
It's sad that nearly 1/3 of the evaporator air flow is completely obscured by the housing and the metal baffle shown in the upper right hand corner of the photo above.
All the more reason for getting the best performance possible out of the system I suppose...

[This message has been edited by randye (edited 03-09-2010).]

quote Originally posted by randye: (I tested the case with a magnet...it's all aluminum)

It's possible that the cylinder block of the HR6 is aluminum with iron sleeves, but I don't think so. I'm pretty sure that the HR6 cylinder block is all iron/steel.

Here is a picture of a V5 compressor. The round port on the far left is where the compressor control valve goes. The other compressors do not have this. V5 is the only ones that do. If it has it you have a V5. 86's had a V belt, 87-88's had serpentine belts. They only came on 2.5's

[This message has been edited by josef644 (edited 03-09-2010).]

The V5 compressor also has a small oil sump and drain plug on the bottom of the case (as installed).

quote Originally posted by Marvin McInnis: The V5 compressor also has a small oil sump and drain plug on the bottom of the case (as installed).

You can see the drain plug in my photo above.

If the accumulator in the front has a low pressure cycling switch with two wires, it will not be a V5 vehicle.

[This message has been edited by josef644 (edited 03-09-2010).]

quote Originally posted by Marvin McInnis: The V5 compressor also has a small oil sump and drain plug on the bottom of the case (as installed).

The drain plug is not always on the bottom, as installed. It's on the side on my 88 duke. You have to unbolt and rotate the compressor to drain in in this case.

I vote DA-6 I had 4 of these and 3 did not have any designation on the tag. The one did say HR-6 and it was from a '87. The other 3 were from a '85, '86, and a January '87.

Mine needs new switches on the end, the one leaks and it's only thing stopping my system from working. Whats a good place to buy them? All the new ones I see have 2 wires.

[This message has been edited by 02greens10 (edited 03-09-2010).]

I also have to replace my ac system and running into problems finding correct parts, so I can't help at all. I have an '87GT 2.8liter same as you and I probably the same type of original ac compressor. I want to use all new parts and I was hoping to go to my local autozone and order an HR6 compressor and all the switches and valves, accumulator and everything, but if it is not the o-rings being captive or nor-captive, pressure switches on the rear being superseded with two terminal switches, no one seems to have the correct info. Dealer, parts stores, manufacturers all tell me different stories and they have the correct info not the other guy. So if anyone that has actually converted an '87 2.8l v6 ac system to R134a with new parts would list the part numbers and where they purchased it would be appreciated.

[This message has been edited by speed1 (edited 03-09-2010).]

quote Originally posted by speed1: I also have to replace my ac system and running into problems finding correct parts, so I can't help at all. I have an '87GT 2.8liter same as you and I probably the same type of original ac compressor. I want to use all new parts and I was hoping to go to my local autozone and order an HR6 compressor and all the switches and valves, accumulator and everything, but if it is not the o-rings being captive or nor-captive, pressure switches on the rear being superseded with two terminal switches, no one seems to have the correct info. Dealer, parts stores, manufacturers all tell me different stories and they have the correct info not the other guy. So if anyone that has actually converted an '87 2.8l v6 ac system to R134a with new parts would list the part numbers and where they purchased it would be appreciated.

I am NOT by any means an expert on this, but I'm treating this as a learning experience and I'm very happy to share whatever I learn in this thread.

The purpose of my A/C "overhaul" is the same as yours; to convert the system over from R12 to 134a using new parts.

A few things I think I've learned so far:

The DA6 compressor is NOT desirable for use with 134a

The Harrison HR6 compressor IS desirable for the conversion.

Sometime during the 1987 Fiero GT production series GM changed over from the DA6 to the HR6 compressor in 2.8L V6 cars.

The label on the Harrison HR6 compressor seems to usually have the actual designation "HR6" on it.
If it doesn't, it's suspicious, as DA6 and HR6 compressors are identical externally.

It is EXTREMELY difficult to sort out what switches to use for the compressor high cut-out and the low cut-out
Thus far I have found that "Factory Air / 4 Seasons" brand seems to have at least 4 different switches for both the high side and low side shown as applicable for the 1987 Fiero with 2.8L V6 engine
They are all 2 terminal switches now, (can't find single terminal switches unless you get lucky and find some NOS somewhere)
No description is offered as to *why* there are 4 different high pressure switches or 4 different low pressure switches.
None of the switches seem to have any manufacturer data available giving the opening and closing values of the various switches.
There is no descrition given as to why all the switches have different color coding.
One would assume that the color coding must relate to the operating values of the switchs, but I can find NO data anywhere.
I did purchase a "Factory Air 4 Seasons low pressure switch, P/N 35974
A small sticker on the body of the switch says:
"H10"
"OFF 30.0 Kg"
"ON 15.0Kg"
I'm assuming that this must be Kg / cm2, (it's supposed to be a PRESSURE switch ), but the 30.0 "off" and the 15.0 "on" values don't make sense to me.
The 1987 Factory Service manual , (section 8A-64-0), says that the low pressure switch OPENS below 8 PSI

More later...If I don't give up in frustration at this point

[This message has been edited by randye (edited 03-09-2010).]

I have not studied up on this lately. I learn it slow and forget it fast...

I can add that the v-5 compressor is considered a variable output compressor and therefor does not need or use a compressor cycling switch.

Charlie

The DA6 / HR6 compressor as used with V6 engines has two switches at the hose end of the compressor - one red and one white.
It is my understanding, that both are high pressure switches.

The red switch is a high pressure cut-off switch, used to cut power to clutch coil when the high-side pressure becomes too great.
open pressure: 430 psi +/- 20 psi. reclose pressure: 200 psi +/- 50 psi.

The white switch is used to turn on the radiator / condenser cooling fan.
The switch closes at pressure of 280 psi. Some have made comments that this is not required, as switching on the AC, the fan is switched on through the Heater / AC control. The white switch could just be a safety backup .

As you have found, single pin switches have been replaced by a new design using two pin connectors. The additional second pin is connected to ground. In the old, single pin switches, the ground connection is made by the outside body of the switch and the case of the compressor.
The 1988 Factory Service Manual has info on the switches for the stock AC systems using R12.

quote Originally posted by randye: Am I missing something here?

There are a total of three pressure switches in the CCOT (clutch cycling orifice tube) A/C system used in the V6 Fieros:

1) The "Pressure Cycling Switch" mounted on the accumulator serves two functions. It cycles the compressor clutch on and off to modulate cooling performance during normal A/C operation, and it also serves as a low pressure cutoff switch to protect the compressor in case of refrigerant loss.

2) The "Coolant Fan A/C Pressure Switch" is mounted on the rear head of the compressor. It is a normally-open (NO) switch that closes at pressures greater than 280 psi (according to the GM/Helm FSM), and it is intended as a backup to turn on the radiator fan if the refrigerant pressure goes significantly higher than normal, which also implies a refrigerant temperature much higher than normal.

3) The "A/C High Pressure Cut-Out Switch" is also mounted on the rear head of the compressor. It is a normally-closed (NC) switch that opens (and thus disengages the A/C clutch) at pressures greater than 425 psi (per GM/Helm). Its sole function is to protect the compressor (and probably the rest of the system) in case of a gross overpressure condition ... as might result from a blockage somewhere in the system.

So, you can see that both switches on the rear head of the DA6/HR6 compressor in a V6 Fiero are high-pressure limit switches, which explains why they share a common manifold and why either switch will function properly in either hole.

Incidentally, only the V5 compressor, as used in the 4-cylinder Fieros, uses a low-pressure cutoff switch mounted on the compressor itself. This is necessary simply because the V5 system doesn't have a Pressure Cycling Switch to provide the same functionality.


Edit: StockGT beat me to it. He posted the correct information while I was researching and typing my reply. I guess great minds do think alike.

[This message has been edited by Marvin McInnis (edited 03-10-2010).]

quote Originally posted by Marvin McInnis: There are three pressure switches in the CCOT A/C system in the V6 Fieros: 1) The "Pressure Cycling Switch" mounted on the accumulator serves two functions. It cycles the compressor clutch on and off to modulate cooling performance during normal A/C operation, and it also serves as a low pressure cutoff switch to protect the compressor in case of refrigerant loss. 2) The "Coolant Fan A/C Pressure Switch" is mounted on the rear head of the compressor. It is a normally-open (NO) switch that closes at pressures greater than 280 psi (according to the GM/Helm FSM), and it is intended as a backup to turn on the radiator fan if the refrigerant pressure goes significantly higher than normal, which also implies a refrigerant temperature much higher than normal. 3) The "A/C High Pressure Cut-Out Switch" is also mounted on the rear head of the compressor. It is a normally-closed (NC) switch that opens (and thus disengages the A/C clutch) at pressures greater than 425 psi (per GM/Helm). Its sole function is to protect the compressor (and probably the rest of the system) in case of a gross overpressure condition. So, you can see that both switches on the rear head of the DA6/HR6 compressor in a V6 Fiero are high-pressure limit switches, which explains why they share a common plenum and why either switch will function properly in either hole. Incidentally, only the V5 compressor as used in the 4-cylinder Fieros has a low-pressure switch mounted on the compressor itself. This is necessary because the V5 system doesn't use a Pressure Cycling Switch. Edit: StockGT beat me to it. He posted the correct information while I was researching and typing my reply. I guess great minds do think alike.

Thanks again to you Marvin and to StockGT!

My frustration with identifying and procuring the proper switches is apparent.
So much so that I'm obviously looking for a "work-around", if that's at all possible.

The good news is that I did manage to locate and purchase what appears to be the proper high pressure, (red) switch today.
It was found on the shelf of a local custom hose shop that stocks such older, odd items.
The bad news is that this switch *rattles* internally when you shake it gently which gives me pause about its operability.

As for the white switch, while I'm not particularly proud of the solution, I managed to salvage the old switch by crimping a male spade connector onto the brass terminal post on the switch and covering it partially with a short piece of heat shrink tubing. (see my earlier photos above)
The "mushroom" shaped portion of the plastic broke apart when I removed it from the old compressor.
I figure that I can modify the harness connections by removing the OE connector and replacing it with a female spade connector and covering the whole connection with more heat shrink tubing to "weatherproof" it.
In light of the new information from you and StockGT, I'll take another look at the 2 terminal switch I got to replace the white one. Perhaps those 30.0 Kg and 15.0 Kg close and open values will make some sense now.
I hate to guess at these switches are they are typically approx. $30 - $40 each now.

I forgot to mention that I found it is ok to disregard the color as long as the switch is correct for the application. On my quest, I found the correct switches but the colors were not the same as the old ones. I apologize that I do not have the part numbers any more...

Charlie

quote Originally posted by cptsnoopy: I forgot to mention that I found it is ok to disregard the color as long as the switch is correct for the application. On my quest, I found the correct switches but the colors were not the same as the old ones. I apologize that I do not have the part numbers any more... Charlie

Thanks Captain
If you manage to recall or find those part numbers and manufacturer, it would be very helpful.
At this point I'm seriously considering putting my old switches in the new compressor and keeping my fingers crossed!

quote Originally posted by randye: My frustration with identifying and procuring the proper switches is apparent.

A/C parts manufacturer 4 Seasons is probably the best source of information available today, their parts are widely available, and virtually everybody else will cross-reference to the 4 Seasons part numbers. Here is what their on-line eCatalog lists for your Fiero:

Condenser fan switch:

35969 ... 240 psi (on), 170 psi (off); gray; 2 terminal
35972 ... 283 psi (on), 210 psi (off); purple, 2 terminal

High-pressure cut-out switch:

35961 ... 430 psi (off), 200 psi (on); blue; 1 terminal; replaces flared red 1-terminal switch
35974 ... 430 psi (off), 200 psi (on); red, white, or blue; 2 terminal; replaces red, white, or blue switches with round connector

The 4 Seasons eCatalog also lists the proper connectors for each switch. Happy hunting.

[This message has been edited by Marvin McInnis (edited 03-10-2010).]

quote Originally posted by Marvin McInnis: A/C parts manufacturer 4 Seasons is probably the best source of information available today, their parts are widely available, and virtually everybody else will cross-reference to the 4 Seasons part numbers. Here is what their on-line eCatalog lists for your Fiero: Condenser fan switch: 35969 ... 240 psi (on), 170 psi (off); gray; 2 terminal 35972 ... 283 psi (on), 210 psi (off); purple, 2 terminal High-pressure cut-out switch: 35961 ... 430 psi (off), 200 psi (on); blue; 1 terminal; replaces flared red 1-terminal switch 35974 ... 430 psi (off), 200 psi (on); red, white, or blue; 2 terminal; replaces red, white, or blue switches with round connector The 4 Seasons eCatalog also lists the proper connectors for each switch. Happy hunting.

I wish I could give you another "+" Marvin.
You're an enormous help sir.
I did look at the 4 Seasons ecatalog yesterday, but did not find the pressure operating values.
THANK YOU.

My frustration with deciphering the switches is greatly eased.....now to actually *get* them.
Advance Auto Parts here in Florida carries Factory Air / 4 Seasons, but none of their stores within a 30 mile radius of me has them in stock.
All are special order.

My progress on the A/C rebuild thus far:

Remanufactured HR6 compressor from Factory Air / 4 Seasons, PART NUMBER: 57255 ($160.99)
Variable orifice tube, (normal climate) from Factory Air / 4 Seasons, PART NUMBER: 38902 ($20.99)
New accumulator, (receiver - dryer), from Factory Air / 4 Seasons, PART NUMBER: 33181 ($29.19)
2 terminal, high pressure cut-off switch from Factory Air / 4 Seasons, PART NUMBER: 35974 ($27.00)
2 terminal condenser fan switch from Factory Air / 4 Seasons, PART NUMBER: 35969, ($29.79)
134a o-ring conversion kit from Factory Air / 4 Seasons, PART NUMBER: 26735 ($5.49)
New A/C belt from Dayco, PART NUMBER 15370, (probably switch to Dayco, #13780 per a tip in this thread...) ($15.00)
8 ounce bottle of 100 viscosity Ester oil labeled to be approved for R12 to 134a conversion ($7.00)
A small bottle of UV dye, a small amount, (< 1oz.), of which is to be added to the Ester oil for leak checking later. ($4.00)

PARTS TOTAL, (excluding A/C flush chemicals) = $299.45

My evaporator core has been removed from the car, flushed and throughly cleaned inside and out.
All A/C lines have been throughly flushed, cleaned and blown out with high pressure air. (1 gallon each of commercial A/C flush solvent and denatured alcohol)
The condenser has been flushed and blown out with compressed air as throughly as possible without removing it from the car. (30 minutes of repeated solvent / alcohol and air through it until no evidence of oil coming out of it)
No evidence of "Black Death" in the system, only a lot of "goo" from improperly mixed oils and some A/C "stop leak" that had clogged the orifice tube screens.
The hot - cold mixer door in the blower housing has been readjusted and is operating properly now.
New 134a conversion o-rings are installed on all the line fittings.

I think I'm about ready to start reasssembling the system once I get the compressor switches.

[This message has been edited by randye (edited 03-11-2010).]

Don't use the recommended AC belt. Click here for more info.

quote Originally posted by randye: I did look at the 4 Seasons ecatalog yesterday, but did not find the pressure operating values.

For future reference, in the tabular (Application) listing just click on a part number to see the detailed specs for that item. From there, clicking on the Application tab will take you back to the tabular listing.

[This message has been edited by Marvin McInnis (edited 03-10-2010).]

Randye, I'm following the thread closely for the part numbers and where I can get the same switches. I had gathered most of the parts I need except the switches. I had contacted AC Delco, 4 Seasons, Ready Aire, and other ac vendors and none of them could give specific parts numbers or even how to install the two terminal switch. Since you are actually doing this on the same type of car I have, I can see what I actually available to purchase.

quote Originally posted by TopNotch: Don't use the recommended AC belt. Click here for more info.

Fantastic!
Thanks for the tip. I'll swap out belts for the Dayco 17380 or 17390.
A "+" for you sir.

The a/c compressor is shot on my 1987 gt 2.8L , it's a 1131469 Harrison, I guess from what i read that makes it a DA6 model. so if i'm looking for a HR6 to replace it, what would i search for.? all the reman ones i see on Ebay are listed for the 2.5L engines.. are they the same? any thoughts? sorry I didnt mean to hijack your thread.

Hi Randye

Seeing that the DA6 is not a good compressor for the conversion, should I replace mine that has been working for the last 10 years+ with no problem?

quote Originally posted by LT188GT: Hi Randye Seeing that the DA6 is not a good compressor for the conversion, should I replace mine that has been working for the last 10 years+ with no problem?

Yes.
It's going to explode any moment now!

Seriously though Clem, I'm only going on what I've read here on PFF and some brief studying.
I haven't seen where anyone has specifically said that the DA6 is a *good* choice for a 134a conversion.
As an engineer I tend more toward empirical data than anecdotal evidence. What I do know is that the HR6 is an improved design iteration from the DA6.
With that in mind, and since I don't want to reuse any old parts that I think might be questionable, I went with the HR6
I'm sure the DA6 probably would work ok, and yours is at least some evidence that it does.

[This message has been edited by randye (edited 05-09-2011).]

quote Originally posted by jsketcham: The a/c compressor is shot on my 1987 gt 2.8L , it's a 1131469 Harrison, I guess from what i read that makes it a DA6 model. so if i'm looking for a HR6 to replace it, what would i search for.? all the reman ones i see on Ebay are listed for the 2.5L engines.. are they the same? any thoughts? sorry I didnt mean to hijack your thread.

Yours is the same model number as my old one, so yep, that makes it a DA6!
If you want an HR6 I would forget the Ebay stuff and just find a distributor or auto parts store in your area that can order you a remanufactured Factory Air / 4 Seasons HR6.
It's impossible to tell what you'll get off Ebay when it comes to A/C parts and from all the confusion and misinformation I've gotten from parts suppliers, I can only imagine what horrors you might get into with Ebay A/C parts.

The parts list and numbers I have in this thread should help you.
Our resident A/C experts here have been very patient with my ignorance and helped me compile the list.
It's one of the reasons I started this thread.
I couldn't find all the definitive info in one place searching the archives here on PFF, and I have no problem asking dumb questions.

My compressor, (original) has the Harrison decal on it, it Says Model # 1131469, but doesn't say hr6, vr5 or anything like that only has a place for the 2 switches on the end, none in the side.(1986-2.8 , "V" groove) So, What is it I've got? What to ask for ? Thanks