Automotive Air Conditioning Information Forum

This morning already, before I depart for Prescott, I used aerosol brake cleaner and brushes to clean up the top of the compressor and the fittings, then washed that off with water. Then I took the truck to Home Depot and used the AC. When I returned, I saw a small ring of dye around the bolt securing the high pressure line (the one I replaced in 2017). So pretty sure my small leak is from the O-ring on the high side fitting to the compressor.

I see you list a new discharge line for my truck https://www.ackits.com/1998/nissan-1424 ... -24l-12234 but wonder if I'd need to cut its fitting depth shorter like I did in 2017; anyway, that's not expensive.

Tim wrote: Sat Sep 13, 2025 7:09 am If you can fit it over the pipe and still connect, try a same-size captured o-ring.

I assume that a "captured O-ring" is just one that fits into a groove. I do have an assortment of new green NBR O-rings already.

As I do not have a recovery machine, I'll likely wait until the R134a leaks out, then fix. Capacity is like 2 cans.

Captured o-rings are just a little thicker. Think of it like an old A6 compressor. There are #12 o-rings for the hose connections. And #12 for the back of the compressor, which are thicker, "captured".

Tim wrote: Sat Sep 13, 2025 9:22 am Captured o-rings are just a little thicker. Think of it like an old A6 compressor. There are #12 o-rings for the hose connections. And #12 for the back of the compressor, which are thicker, "captured".

So I may need an O-ring WIDER than the green one shown in this photo that I used, where the factory black one is wider? Or did time just cause the black one to become wider. Because I'm a little confused about thicker and wider here.


1. If so: where do I obtain one without buying the entire hose from you?

2. If I did buy the hose from you and the fitting depth was too long, I'd simply shorten it, and let you know; I wouldn't return it.

I don't know the size of the o-ring off-hand. I always just matched them up in my Master kit. Autozine and Napa are suppliers of Santech, which is one of the big companies where I still do catalog stuff. The issue is that you can't go by my year, make, or model. Kind of have to match it up. The Santech kit for this vehicle is an MT2571. Might look if it has a better-fitting o-ring.

Maybe:
MT0236-4
MT0244-10

Tim wrote: Sat Sep 13, 2025 9:37 am I don't know the size of the o-ring off-hand. I always just matched them up in my Master kit. Autozine and Napa are suppliers of Santech, which is one of the big companies where I still do catalog stuff. The issue is that you can't go by my year, make, or model. Kind of have to match it up. The Santech kit for this vehicle is an MT2571. Might look if it has a better-fitting o-ring.
Maybe:
MT0236-4
MT0244-10

This morning I tried to look up on official Nissan parts sites for the 1998 Frontier O-ring, and it doesn't appear when searching for a 1998. When I search for my 2004 Frontier, one does show. These two Frontiers use the same AC compressor 14-3138NEW/DKV14C1GR, but have different discharge lines. The 1998 is leaking from O-rings at both ends, was replaced in 2017 due to a pinhole; ackits.com shows discharge line 57-0135 with O-rings on it, is that true?

2004 is leaking from both ports on the compressor but not at the discharge line to condenser connector; I replaced its condenser, compressor, drier and backflushed with solvent in 2018 due to compressor seizure.

I have Santech MT2571, used O-rings from that. I also have another AC O-ring "kit" for Nissan, and an assortment of green refrigeration O-rings from Harbor Freight.

Even though the 2004 does have leakage, the rate of leak is significantly slower than on the 1998, so maybe the 2004 should be treated as "touch up" with 6 oz. R134a where the 1998 should get new O-rings.
Photos of the 1998 leaks

Most likely that hose will come with o-rings. For sure, if I ship from the Texas location. I can check NV on Monday. Spoke with some top brass at the NV site. Says it should have the o-rings as well.

Tim wrote: Sun Oct 26, 2025 1:04 pm Most likely that hose will come with o-rings. For sure, if I ship from the Texas location. I can check NV on Monday. Spoke with some top brass at the NV site. Says it should have the o-rings as well.

Please also check the "depth" of the cylindrical part of the 1998 discharge line that goes into the compressor. The cylindrical fitting on the original Nissan unit extends just 9.5mm but the cylindrical fitting on the aftermarket fitting I purchased in 2019 extended 14mm and I had to try to shorten that up to try to match. See photo.

So it would need to come with 2 O-rings and have that depth into the compressor be about 9.5mm or I won't order as I'd need to return it.

Is that a UAC hose?

It was Murray Climate Control AC Hose - 56134, what I could get the next day up near Prescott. I even called Murray about the different "depths", and sent them a photo, said no one had ever had that issue before, sure.....

Factory compressor still, at 290K miles.

Seeing if I can get someone to check the NV stock. Back when we had the shop and got a fitting like that. I would place a spacer on the end and use a cutting wheel to remove a little of the end. Take off my spacer, used to cut straight and depth. Clean up the end, and always seemed to work out okay.