Converting 86 fiero to r134a (Page 1/1)
chrislayton AUG 16, 10:26 AM
Can anyone tell me what I need to do to convert my 86 fiero to r134a?

There isn't enough r-12 in the system to run it anymore though there is a very little when I check it at the schrader valve

Do I have to completely remove the compressor pump to dump the oil out and change the oil?
steve308 AUG 16, 10:59 AM
Save yourself a bunch of time and go straight to YouTube. Plenty of how to and what u will need info...... It's an easy conversion and it works just fine.
Fastfiero1 AUG 16, 11:46 AM
I converted the 91 S10 Blazer I used to have from R12 to R134a. I am also an experienced auto tech so it was an easy process but it is not too difficult for the avg person to do. At some point a shop will have to be involved to assist with part or all of the process if you don't know anyone that has the right tools and equipment.

The first step is to prep the system.
--If there is still some R12 in there you will have to head to a shop and have the remaining R12 evacuated.
--Once completely empty of R12 you will remove the compressor and drain out any of the oil you can from the compressor (R12 uses a mineral oil that is mot compatible with R134a so it cannot be reused) and then reinstall it. The evacuation process will remove some oil from a lot of the lines as well.
--You will want to replace any o-rings you can easily access with ones suited for 134. (On my Blazer I disconnected all the lines and components and replaced every o-ring and seal I could get to with new ones for R134a).
--You will want to replace the accumulator / receiver drier (The silver thing in front by the spare). The drier / accumulator removes moisture from the system and will absorb some of the R12. replacing this prevents you from contaminating the new system.
Next you can start the retrofit.
--You will want to install you new R134a fittings (these screw right over the existing R12 fittings and usually come with new caps.
--You will want to get the system pulled under a vacuum (This can be done at a shop or done by anyone with a set of A/C gauges and a vacuum pump) to 30in and it should hold that vacuum for at least 15 minutes. this will boil out any remaining moisture that got into the system while components were disconnected.
--After that you can charge the system with the new R134a oil (usually provided in the retrofit kits) and the R134a refrigerant. Keep in mine the charge amounts are different due to the molecule size difference of the 2 refrigerants. you can find conversion charts online via a google search.

Hope this helps you some. Good luck!

Fiero's Owned:

1987 Coupe 2.5 5spd May 99 - June 03
1987 GT V6 5spd July 30 2012 - Current

[This message has been edited by Fastfiero1 (edited 08-16-2016).]

hercimer01 JUL 17, 10:28 PM
What about the orifice tube?

Is the Fiero Store conversion kit any good? Is it complete?

I am getting ready to do some conversions for the first time.

Project Genisis Lo Budget 3800SC swap
12.840@104.8 MPH Intense-Racing 1.9 rockers, 3" exhaust, 3.4 pulley, ZZP tune and 18 year old tires.

88 Coupe under construction SOLD

88 formula 3.4L 4t60 swap SOLD

88GT resurrection in progress.

theogre JUL 18, 02:14 PM
Sadly converting is Not as simple as most YT videos and other claim. Oh You often can do this but not under $50 to $100.

For one thing, Most R12 hoses and seals have problems after ~ 5 to 10 years let alone 30+ years.
Worse, Most old R12 and R134a compressors have bad seals/gaskets and not just main drive shaft seal buried under the clutch. GM V5 and other compressors are well known to leak thru case seems because "rust" on cases stops sealing them.
Either or more likely both are Why you have no R12 now.
If you leak R12 then you will leak R134a and faster because of size of R134 molecules. This is why R134 systems have "Barrier hoses" to prevent R134 going thru the hose material.

Many AC Shop Will Not work on R12 cars now and Many won't work on R12 cars converted to R134a either. Or worse R12 Systems loaded w/ Propane, "Freeze12" and other BS.
Many shops do not have equipment to Legally handle R12 now. Each refrigerate needs a complete set of recover/recharge machines, tanks, etc, to meet state and fed laws/rules.
Takes to much shop time to fix all the things wrong w/ R12 systems or system converting to R134.
Car AC shops Do Not have tools or Insurance to work on cars w/ Illegal refrigerants. EPA may approve X for their SNAP program but USDOT/NHTSA only allows R12 R134a and R1234yf but for only for cars made for R1234yf.

Most DIY "Conversion kits" Do Not have good service valves or no valves at all. Just very simple adapters to fit R134a gauges and tools.
Most DIY do not install even these crap kits right and worse contaminate the system w/ leak stop and other BS that can wreck recover machines.
Than add GM R12 high side valve is Not a simple Schrader valve and have issues right from the factory but old R12 hard valve covers stop or majorly reduce leaks there. Convert to R134 then often that valve leak bad unless you install an adapter w/ a primary valve in it that most Kits Do Not Have and even then they often leak.

TFS and others love to take your money but buying these "conversion kits" and car parts from them is not a good plan more so when they have a Core Charge.
AZ, Advance, and some others you can buy online and local stores take Cores, Returns and Warranty Returns so you don't pay shipping back to X.
Returns because new and rebuild units can be bad right out of the box.

Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

wgpierce JUL 18, 11:39 PM
I used the Fiero store kit, it is complete as far as having adpaters, orings and oil. I didn't use many of the orings, but did use their adapter fittings. Remove schrader valve from existing fitting first. They are bigger than car/bicycle valves and need a special tool. I used a brake line tube with a slot cut in the end to take mine out.
FX JUL 19, 01:56 PM
I have converted many older cars including my 86 Fiero GT over to 134 with no problems, or having to replace the orifice, and they all worked well...Just buy the conversion kit, auto parts store or Walmart etc.. You have to replace the valves, evacuate the system, then just put the oil charge in, then the 134 (use a gauge, some kits come with them). If you don't have the means to evacuate the system, any place that works on them should do it for you (put the 134 replacement valves in first). It won't get as cold as it would if you change the orifice, but quite adequate...The conversion kits come with good instructions...
Old Lar JUL 19, 08:43 PM
I've had both my 87 and 88 GTs converted to 134. Easy to do.. take it to a shop and have a professional do it.