I've been working on a write-up for a while on the different o-ring sizes used on the Fiero, with pictures, diagrams, explanations, etc. Recently I started a new job, and have not had the time to work on it, so I thought I'd post the important information here so people could make use of it, now that it's getting hot outside.
-84 Fieros use different lines and o-ring sizes than the later years, hence the two different tables. -Use 525 Viscosity mineral oil designed for air conditioning systems to lubricate the o-rings, even if converting the system over to R-134A. NAPA sells a quart bottle, which is WAY more than enough, part # 209500
Thank you so much and this chart couldn't have arrived at a better time! Well maybe 5 hours ago. I guesstimated which orings to use from my assortment kit, pulled vacuum, and it's not holding!
When I was installing new Hi/Lo switches I was hesitating. The compressor had black rings already in the grooves. The Santech packages had green Orings and I couldnt decide whether to dig out the black rings from the reman'd compressor or just install the switches with these existing Orings.
Black o-rings CAN be HNBR material, not just the green ones . If your new switches came with o-rings, I'd pull the black ones, lube the new ones, and put those in.
I have not had to use any special "captured" O rings on a Fiero A/C system. All of them (except for the compressor outlet lines) use the standard variety A/C O rings. I use the green R-134a compatible rings. If you have a GM assortment kit with #6, #8 and no 12 A/C O rings you'll be set. Just watch the O ring thickness (material cross section diameter) and match accordingly.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I'm so confused right now. Everyone has varied opinions on what orings to use. To further complicate, I bought a SUPERCOOL tackle box set of o-rings contains 350 orings (part #OR350), and I cannot match it up some of them with the chart up above. It has a printout picture for each compartment but the sizes are all over the place but not specific. UGHHH!!
I made the same mistake and bought a large assortment like that. Basically useless, since the called out sizes don't correspond to what the manufacturers use. I even went as far as to take a set of digital calipers and start measuring them to see the sizes, but they were almost all odd-ball ones.
If you can wait until this weekend, I have in my notes the part number of a small kit that contains almost all the o-rings, for roughly $7, available at most auto parts stores. It's at my parent's house, and I'll be up there then. IIRC it contained all but two of the o-rings for the 84, don't remember on the 85+
Every accumulator I've bought so far has come with o-rings for the accumulator inlet and outlet connections, so that's a couple less to worry about.
I have not had to use any special "captured" O rings on a Fiero A/C system. All of them (except for the compressor outlet lines) use the standard variety A/C O rings. I use the green R-134a compatible rings. If you have a GM assortment kit with #6, #8 and no 12 A/C O rings you'll be set. Just watch the O ring thickness (material cross section diameter) and match accordingly.
You can tell if the connection requires a captured o-ring or not by looking at the line at that connection. A square shoulder means a standard o-ring, while a tapered cone-shaped one uses a captured.
Standard (evaporator to accumulator):
Captured (84 accumulator outlet):
[This message has been edited by RWDPLZ (edited 05-21-2013).]
I don't know about standard or captured but I just replaced all of the O rings on one of my A/C systems and just matched the sizes. No leaks so far. Perhaps you do need captured rings here and there but just matching them has worked. Maybe I'm just lucky!
I don't know about standard or captured but I just replaced all of the O rings on one of my A/C systems and just matched the sizes. No leaks so far. Perhaps you do need captured rings here and there but just matching them has worked. Maybe I'm just lucky!
That's where I've run into problems before, thickness. The condenser O-rings and apparently the manifold connection at the frame rail coming from the compressor may be an issue also. I'll have to check the vacuum on the system again today to make sure.
NAPA # 801745 O-ring kit
This kit appears to have all of the proper size O-rings in it for the 85 up. It's the only one out of the universal kits I purchased that had the proper O-ring for the condenser as matched to the original.
The condenser uses captured o-rings at the inlet and outlet, one being the oddball #6 size, the other #8. The manifold at the frame rail, at the rear of 85+ cars, uses standard o-rings, #8 and #12.
That's where I've run into problems before, thickness. The condenser O-rings and apparently the manifold connection at the frame rail coming from the compressor may be an issue also. I'll have to check the vacuum on the system again today to make sure.
NAPA # 801745 O-ring kit
This kit appears to have all of the proper size O-rings in it for the 85 up. It's the only one out of the universal kits I purchased that had the proper O-ring for the condenser as matched to the original.
is there an equivalent version of the NAPA kit at Autozone? the only reason i ask cause there is an 20% off coupon from AZ available, a penny save is a penny i can spend somewhere else.
Originally posted by Tom Slick: is there an equivalent version of the NAPA kit at Autozone? the only reason i ask cause there is an 20% off coupon from AZ available, a penny save is a penny i can spend somewhere else.
thanks...
That's a tough call because that's a NAPA specific part number in their packaging with no other numbers, so it's likely a NAPA specific kit. It turns out I did have the wrong O-ring at the exhaust end of the compressor hose at the frame rail as indicated by loss of most of the vacuum after 30 minutes. It appears I had a metric o-ring in place and on comparison the standard o-ring was thicker. The o-ring on it initially was incorrect also as it had been crimped on two sides where it stuck out from beneath the sealing surface but it held under pressure. Just make sure you get standard o-rings and measure them if you have to.
[This message has been edited by Joseph Upson (edited 05-25-2013).]
i went to AZ today to return a loaner tool i borrowed. while there i saw an O-ring kit but all the rings were in metric, i guess that is the wrong kit.
[This message has been edited by Tom Slick (edited 07-05-2013).]
Sorry, been busy with work. I just checked Autozone and NAPA's sites, and they don't sell them. Advance does, but none of the stores in my area have any in stock. As far as I know, there aren't any mom-and-pop type shops here downstate, I bet Thirlby's back in Traverse City would have it.
I'll stop by the local Advance and order one, and post the results later.
I stopped by O'Reilly's and they had the part number in their computer, but couldn't even order it. Went to Advance, and they claim it'll be here tomorrow by noon.
I just went through and took inventory of what comes in the 26735 o-ring kit, and it's almost identical, except it has one less #6 standard (not used on Fiero anyway) and DOES include the compressor suction and discharge port o-rings. Otherwise, still missing one #8 captured needed for a full set for a Fiero. It would be the most complete option we have now.
I just went through and took inventory of what comes in the 26735 o-ring kit, and it's almost identical, except it has one less #6 standard (not used on Fiero anyway) and DOES include the compressor suction and discharge port o-rings. Otherwise, still missing one #8 captured needed for a full set for a Fiero. It would be the most complete option we have now.
What is the true difference between standard and captured o-ring? Does them both have round profile, but captured is only thicker?
I chanced o-ring between evaporator and offrice tube, and have a doubt that it may be leaking. Old one had small profile, but I thought it was just formed like that over the years. I replaced it with proximately same size o-ring from FOUR SEASONS 26735 kit.
(I have used ~1300 $ to get A/C working and still I'm at this point. Damn.)
Originally posted by spad: What is the true difference between standard and captured o-ring? Does them both have round profile, but captured is only thicker?
I would like to know the answer to this as well.
in this chart, the Four Seasons shows the same part# for the #8 (standard & capture) o-ring (24131) but the AC Delco shows two different part number.
is this a mistake in Four Seasons or is it okay to use the same o-ring for both standard and capture o-rings?
thanks...
edit: should the #8 part numbers be: captured - 24131 standard - 24608 or vice versa?
[This message has been edited by Tom Slick (edited 07-06-2013).]
I just looked it up, and the #8 standard Four Seasons part number should be 24608, thanks for catching that. I'll edit the data later and re-post the corrected table. The AC Delco numbers are correct.
The difference between the standard and captured is basically the cross sectional area. Standard are thinner, and captured are fatter.
I know this is an old thread but I never saw it. The chart will come in handy. I do find it ironic though that every part number I looked up for these o-rings says "Does not fit your 1986 Fiero" But, I think on Amazon, unless it`s a vehicle specific part it will say that.
Still some great info here. I sometimes have trouble matching O rings but have a large assortment of them. If I am not sure I just measure them with a caliper both OD and cross section (thickness) and go from there. If the NAPA kit works as stated that should eliminate most of the matching problems. Its may not always be necessary to replace all of the old black O rings with the green compound rings when doing a conversion. We've done some where we left the old ones in place at non-critical locations and the system remained tight and leak free for years. What we have noticed is that the high and low side Schrader valve fittings, the switch port and fill port are often leak points.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by RWDPLZ: -Use 525 Viscosity mineral oil designed for air conditioning systems to lubricate the o-rings, even if converting the system over to R-134A. NAPA sells a quart bottle, which is WAY more than enough, part # 209500
Both are used as thread & seal sealer/lube for AC jobs of all kinds. Not aftermarket items to seal leaks in a close system. Google Amazon etc for them to find different sizes. (Leak Lock is no longer available thru Supercool as my cave said.)
Is a old thread but keeps refrigeration sealer/lubes w/ o-ring sizes...
------------------ 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)
