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2.8V6 AC Compressor - all years the same? by Boostdreamer
Started on: 11-14-2012 10:46 AM
Replies: 19 (1938 views)
Last post by: sricka01 on 03-27-2014 02:13 AM
Boostdreamer
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Report this Post11-14-2012 10:46 AM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I just bought a beautiful '86 GT and one of the few things wrong with it is the AC doesn't blow cold. I know it won't be an issue any time soon but I definately want it fixed. This is my 5th Fiero and it will be the first one that has working AC.

I have a Formula parts car and as far as I know, the AC system is still closed. Would it be worth the effort to try to use the compressor from the parts car?

I don't know beans about a car's AC system. I've never worked on one but I'm not afraid to try. I'd rather buy tools than pay labor.

Also, do all 2.8 V6 Fieros have interchangeable AC compressors?

Thanks,

------------------
Jonathan
23K mile '85 notchie - Still under construction
http://www.fiero.nl/forum/Forum2/HTML/121056.html
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Report this Post11-14-2012 10:55 AM Click Here to See the Profile for RWDPLZClick Here to visit RWDPLZ's HomePageSend a Private Message to RWDPLZEdit/Delete MessageReply w/QuoteDirect Link to This Post
The V6 compressors are all interchangeable, but they're not all the same. Sometime around 1987, GM switched from the older DA6 compressor to the HR6 compressor, which is an improved version. Externally, they really are identical, which makes telling them apart nearly impossible if the original label isn't there or legible. The DA6 compressor is not rated for, or recommended be used in, R-134A conversions.

The 88 Formula, if it has the original compressor, would definitely have come with the HR6. It would definitely be worth a shot to use, if the system is sealed, and if you take out the orifice tube in the front compartment, and it's clean. There are several good threads on here now about AC repair, but the main points are

-new orifice tube and accumulator
-8 ounces of mineral oil for an R-12 system, or 8 ounces of PAG oil in an R-134A system. If reusing an old compressor, PAG150 viscosity.
-2.5lbs of R-12 or 80-90% of that for R-134A

[This message has been edited by RWDPLZ (edited 11-14-2012).]

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sardonyx247
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Report this Post11-14-2012 03:25 PM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
Also the 84' compressor is the same as the 85-87 V6 DA6 compressor. FYI
But if you are doing a 134a conversion as said above the better compressor is the 88 V6 HR6.

------------------
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Boostdreamer
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Report this Post11-14-2012 06:29 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Good info guys. Thanks. I guess I won't get to use it for a while but this will get me started.

Jonathan
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Marvin McInnis
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Report this Post11-15-2012 09:47 AM Click Here to See the Profile for Marvin McInnisClick Here to visit Marvin McInnis's HomePageSend a Private Message to Marvin McInnisEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

I just bought a beautiful '86 GT and one of the few things wrong with it is the AC doesn't blow cold. I know it won't be an issue any time soon but I definately want it fixed.



Why do you assume that the compressor is bad? "If it ain't broke, don't fix it."

[This message has been edited by Marvin McInnis (edited 11-15-2012).]

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Report this Post11-15-2012 12:52 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Marvin McInnis:


Why do you assume that the compressor is bad? "If it ain't broke, don't fix it."



I bought the car from a local used car dealer who had the car for about two years. He said he sent the car out to have the AC fixed and that is what he was told the problem was. I guess he didn't want to invest whatever money they were asking for the service. I have no reason to doubt this story. He used to be my father-in-law.

Jonathan

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Report this Post07-01-2013 03:30 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I started messing with the AC system. I worked on the Formula's compressor but it was almost impossible to remove the belt from it. The experience did teach me how to do it though. I bought a 15mm combination wrench from Advance for about $9. Could have gotten it cheaper at China Freight but it would have cost me about 2 hours and 50 miles. I cut the open end of it off so the box end and remaining handle was 6 inches long. That is the maximum length of wrench that can be used between the 2.8 and the firewall. Also, the box end will stay put better while trying to get leverage on it.



Then I cut a section of old garden hose and slid it on the handle and taped it to the wrench. This provided a brake for the ratchet strap that I used to pull the wrench to get the top pivot bolts loose. The hose kept the strap from sliding down the handle. The strap got better leverage out near the end, obviously.



Yes, the pivot bolts were that tight. In fact, that is the reason I believe the auto shop told the PO that the compressor was bad. I think they were too lazy to do the work necessary to put a belt on it and try it. That still could be true, though. This is the original compressor and it might be history.

With the wrench in place, I looped the ratchet strap over it and connected it to the 4-bolt plate that fits under the gas tank. I had to re-set it and pull it several times to get it loose but it worked. I had to loosen the pivot bolt that is closer to the driver's side from the top. I used a long 2x4 wedged near the battery against the fire wall. Then I looped the strap around the wrench and attached it to the far end of the 2x4. Then I used the scissors jack between the strap and the 2x4 to force that bolt loose. That worked also. With both pivot bolts loose, I was able to put a belt on.

After the belt was on and the compressor was tightened back up, I put the alternator belt back on and tightened it. The compressor isn't locked up but it also doesn't create cold air. I've decided to do the work myself on this AC system. When I'm done, I'll do a "How To" thread. This will be my first AC system that I've worked on. Stick with me! I'm going to need your help!

------------------
Jonathan

'68-69 GTO Nose - The Project has Begun!
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Report this Post07-01-2013 03:35 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post

Boostdreamer

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My next question is about the AC relay that is mounted beside the fuel pump relay on the firewall near the air cleaner. What is its function? How do I know if it is doing what it is supposed to do? Is there an easy test to see if it's working without taking it off and bench testing it?

------------------
Jonathan

'68-69 GTO Nose - The Project has Begun!
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Report this Post07-01-2013 04:50 PM Click Here to See the Profile for masospaghettiClick Here to Email masospaghettiSend a Private Message to masospaghettiEdit/Delete MessageReply w/QuoteDirect Link to This Post
Does the compressor cycle at all? If not, it's probably empty of refrigerant and would be a perfect time to put a new accumulator and orifice tube in.
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Report this Post07-01-2013 05:41 PM Click Here to See the Profile for infinitewillSend a Private Message to infinitewillEdit/Delete MessageReply w/QuoteDirect Link to This Post
.

[This message has been edited by infinitewill (edited 01-05-2016).]

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Report this Post07-01-2013 05:51 PM Click Here to See the Profile for RWDPLZClick Here to visit RWDPLZ's HomePageSend a Private Message to RWDPLZEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

My next question is about the AC relay that is mounted beside the fuel pump relay on the firewall near the air cleaner. What is its function? How do I know if it is doing what it is supposed to do? Is there an easy test to see if it's working without taking it off and bench testing it?



It's function is to energize the compressor clutch, and is controlled by the ECU or the pressure cycling switch on the accumulator. You know it's doing what it's supposed to do if the compressor cycles on and off, and you get cold air. It's easier to bench test off the car than on, you just have to unplug it and unbolt it. You can test it just like a conventional relay with a 9V battery and a multimeter.
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Report this Post07-01-2013 06:05 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by masospaghetti:

Does the compressor cycle at all? If not, it's probably empty of refrigerant and would be a perfect time to put a new accumulator and orifice tube in.


Not sure what you mean by cycling.

J

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Report this Post07-01-2013 06:23 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by RWDPLZ:

It's function is to energize the compressor clutch, and is controlled by the ECU or the pressure cycling switch on the accumulator. You know it's doing what it's supposed to do if the compressor cycles on and off, and you get cold air. It's easier to bench test off the car than on, you just have to unplug it and unbolt it. You can test it just like a conventional relay with a 9V battery and a multimeter.


Thanks! That helps a lot! I definately didn't get cold air. But I also am not sure what cycling is. I just went out and started it up to see if I could hear any fluctuations in idle, etc. I flipped from Max to Vent a few times but I can't tell that it does anything other than engage the radiator fan. It definately does that.

J
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Report this Post07-01-2013 06:43 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Easy AC relay test----swap it out with the fuel pump relay and see if the car starts. You should hear and can feel the relay click when the ignition is turned to the ON position.

The cycle switch up front on the accumulator should be replaced. Though they seldom go bad, it's a possible culprit for no AC. You can test the clutch and compressor by inserting a paper clip into the accumulator harness. I would only do it briefly with the engine running just in case the system is dry. Have someone watch the compressor clutch for activation.

If the system has been converted to 134a you should have the larger size schrader valve on the accumulator. If the PO filled the system with 30-32oz. of 134a then it could be over-pressured and will not cool. One of my cars was overcharged so I drained the refrigerant and added 2 12 oz. cans back to the system and it works great. 30 oz. x .8 = 24 oz.
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Report this Post07-02-2013 09:38 AM Click Here to See the Profile for masospaghettiClick Here to Email masospaghettiSend a Private Message to masospaghettiEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cycling is the compressor turning itself on and off. The compressor is either on or off - it doesn't run at partial load - it will turn on when the pressure in the system reaches a certain threshold (~50 psi?) on the low pressure side, and then turn off when the pressure drops to ~25 psi. The cycling is the compressor maintaining this range of pressure.

If the compressor cycles then the system is basically functioning and you know the a/c clutch, relays, and switches are all (or mostly) functioning as they should, and you probably are just low on refrigerant (but not completely empty, because the compressor will not cycle on an empty system). If the compressor doesn't cycle, you don't know if you're just out of refrigerant, or if you have some other system problem.

[This message has been edited by masospaghetti (edited 07-02-2013).]

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Report this Post07-02-2013 05:04 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for the description of cycling. I kinda figured that but it never hurts to confirm. My compressor did cycle a little bit when I jumped the cycle switch with a paperclip. I decided that that switch might be bad so I swapped it with one from my parts car. When I took it off, I heard a little hiss of a pressure release! That was great news to me! I decided to go get it checked. It only had a quarter of a pound of R-12. He pulled it all out and let it sit with a vacuum on it for about 5 minutes. It held 30 inches of pressure (if I'm saying it right), you know what I'm talking about. Anyway, he put 2.5 lbs back in (that's according to the sticker from the factory under the front hood. I told him I thought it was 3 lbs but he wanted to go by the book. It was working for about 5 minutes then my old crappy belt broke. I expected that. Not a problem. I've done it once now and I can do it again. I wanted to start with an old belt to begin with because the car has not had a belt for some time. I expected rust, etc to be harsh on the first belt. I've got a back up that I'll put on tomorrow. He put dye in for future reference if I develop a leak.

He was extremely nice and knowledgeable. Very up-front about prices, services, techniques, and machines. He even had Fiero experience! I didn't have to tell him anything. He knew where everything was. I'd recommend him for any auto AC service.

Brown's Auto and Air Conditioning.
Center St. Kingsport, TN

------------------
Jonathan

'68-69 GTO Nose - The Project has Begun!
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Report this Post07-02-2013 06:02 PM Click Here to See the Profile for RWDPLZClick Here to visit RWDPLZ's HomePageSend a Private Message to RWDPLZEdit/Delete MessageReply w/QuoteDirect Link to This Post
The factory R-12 capacity is 2.5lbs. Glad to hear a shop treating a Fiero well for once, especially on AC work.
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Report this Post07-02-2013 09:50 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
2.25 lbs of R-12, the dye, and the labor came to about $185. $130 for the R-12, $12 for the dye, $40 for the labor, plus tax.

He said that all R-12 systems leak a little bit and I shouldn't be surprised if I need another shot next summer. I may still have to decide if I want to change over to 134A. He told me that he fills 134A systems by evacuating the whole system and putting back what is required. He says that is the only correct way and that his equipment is very accurate. He says the 80% rule is close but not close enough for him. He said he has a formula for it or maybe the machine knows the conversions. Anyway, he doesn't want to slap a shot in there and roll the dice. I like that. I wish every mechanic was that meticulous about his work!

I will go to Home Depot tomorrow and buy a small turn buckle to make a spreader for between the pulleys. I doubt I got either of my belts tight enough. I wish there was a better way to measure the tightness of belts. I don't want to OVER do it!

Also, everyone who helped gets a plus unless I've already given it to you!

I'll post pics and updates if there's anything else to tell.

------------------
Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

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Report this Post07-04-2013 10:30 PM Click Here to See the Profile for BoostdreamerClick Here to Email BoostdreamerSend a Private Message to BoostdreamerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I made a spreader similar to what is seen on the Fierosails page. I encountered a problem with it, though. the fact that the blocks could pivot around the eye bolts made it possible for the spreader to expand diagonally instead of pushing directly against the two pulleys. I solved this problem by making wooden washers to hold everything square. I also had to cut the smaller block more narrow so it could also work with the alternator and not press against the belt giving a false sense of tightness.

I got my second belt on yesterday and all is well. It blows cold air almost instantly. I'm incredibly happy with the way it turned out. If it only lasts one summer, I'll consider it money well spent. At least I'll know my system is fully functioning even if it is aging. I don't expect it to last forever so I know an upgrade is in the future somewhere.

------------------
Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

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Report this Post03-27-2014 02:13 AM Click Here to See the Profile for sricka01Send a Private Message to sricka01Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Boostdreamer:

I just bought a beautiful '86 GT and one of the few things wrong with it is the AC doesn't blow cold. I know it won't be an issue any time soon but I definately want it fixed. This is my 5th Fiero and it will be the first one that has working AC.

I have a Formula parts car and as far as I know, the AC system is still closed. Would it be worth the effort to try to use the compressor from the parts car?

I don't know beans about a car's AC system. I've never worked on one but I'm not afraid to try. I'd rather buy tools than pay labor.

Also, do all 2.8 V6 Fieros have interchangeable AC compressors?


Thanks,




Use Randyes method of removal. Very simple but "why didnt I think of that?!" easy! Look at his pic for clarity. You simply stick the socket extension through the rear bracket, stick on the 15mm socket, and finish up the front bolt removal. Did two Fieros last summer.

http://www.fiero.nl/forum/A...120111-2-108922.html

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