Automotive Air Conditioning Information Forum

In 2017 I had a pinhole leak in the high pressure line of my 1998 Frontier; factory hoses were discontinued and aftermarket hose had different depth at one fitting; so I was able to cut to a shorter depth and make it work.


A month ago, I last traveled down to Phoenix, was 115F that day. I drove my 1998 Frontier to store to pick up Mrs. Cusser's Rx and noticed that the AC didn't seem to be working as well as it should be, but it was too hot to investigate those that day.

So I went back 2 weeks later, threw AC gauges on it - half expecting high side pressure to be low due to an R134a leak, but pressure was over 325psi at maybe 2000 rpm. I felt the low side schrader was leaking, and that maybe the cap was faulty too. I misted the AC condenser with water and high pressure dropped; so I rolled up some newspaper and checked the fan clutch, and the rolled newspaper easily stopped the fan. So I removed the fan clutch using my special ultra-long 10mm wrench and swapped it for a new fan clutch at O'Reilly, and installed that. The previous fan clutch lasted 47K miles. Next morning though, the AC was still performing sub-par, and previously had great AC.

Monday, there was still enough refrigerant in the system to engage the compressor, and low pressure line from evaporator wasn't even cold, and high pressure reading was lower due to new fan clutch. I hadn't added any refrigerant since 2017. Rather than spend time in 120F garage to evacuate the system to replace the leaking low side schraeder valve then pull good vacuum and refill from scratch (25 oz.), I chose to add 12 oz. of pure R134a (one can, the R134a capacity is listed at 25 oz.) and use a new low pressure valve cap (the real seal). AC looked good after that, good vent temperatures at least 45F leak checked the low side cap and found no leaks so calling it good.

So I'm figuring that the refrigerant leak was a bad low side schraeder coupled with a leaky low side cap. The cap is the real seal on auto AC systems. So I violated a cardinal rule of auto AC and just added refrigerant without knowing how much remained in the system, I know. But it worked assuming the replacement valve cap holds up.

Excellent, would love to know your hi and lo now after the 134 infusion.
Seems this hot-swap core tool has your name on it. It has come in darn handy here
https://www.google.com/search?client=fi ... rader+tool

Have to wonder what that allen hex is for in the pic

tbirdtbird wrote: ↑Wed Aug 10, 2022 1:09 pm Excellent, would love to know your hi and lo now after the 134 infusion.

Well my 1998 Frontier does not have a tachometer, so I had to guess what was about 2000 rpm to add R134a and take pressures. So low side was about 30-35psi and high side was about 180psi.

tbirdtbird wrote: ↑Wed Aug 10, 2022 1:09 pm Have to wonder what that allen hex is for in the pic

I did notice that hex, but didn't touch that. I think that is the high pressure relief valve; when I search Google, I see some that look like it. I seem to see a spring looking down at the new one in the photo.

I think I may still have that old line somewhere, may take apart if I find it.

Tbirdtbird, do you happen to know whether that Mastercool Schrader Valve Removal Tool will work with the larger diameter valves, like those that Toyota uses? From outward appearances, it doesn't seem so.

John, I am pretty sure it does not.
I have wondered if there is an equivalent tool for the larger schraders. A poster somewhere said he had to drill out the bore a smidge to have it accommodate a larger schrader. Not sure what car it was.
At some point I plan on doing a search to see if one exists

These gizmos started out for residential HVAC, was glad someone had the idea to cross it over to mobile.
Dave

EDIT:
OK, here is one that says good for 1/4" and 5/16"
Is the Toyota size 5/16?
https://www.amazon.com/Mudder-Remover-A ... 72&sr=8-61

For the price it is almost worth getting it and trying it

I just pulled a new Toyota Schrader out of my stock, and it measures 1/4" at its widest point using calipers.

OK, let me use a drill index to determine the bore on my gizmo
Might not post back until tomorrow

OK, JOhn, here are the numbers from my hot swap schrader tool (had to retrieve it from my nephew)
The ID of the adapters and the body is about .265....ie just a tad over .250

I just measured the diameter of a common so-called standard schrader core (designed for a standard 1/4 flare fitting) with dial calipers and I got .200
If you are at .250, I think this would work. This is Mastercool 81490. It states for 5mm valve cores only. 5 mm equals .196"

The passageway is a tad over .250, so I would think it would work.

The next size up in my assortment (after .200) is .235, and it fits the passageway. I do not have any .250 cores. The kit I have has some bizarre sizes that I have never needed, but you do more AC than I do.

Perhaps the only way to know for sure is to get one and try it. It is not expensive

Dave

Thank you, sir. I'll investigate this further.

Please share your findings