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Help- identifying 1998 Corvette high side schrader valve

eric w on Tue June 28, 2011 9:34 PM User is offline

Year: 1998
Make: Chevrolet
Model: Corvette
Engine Size: 5.7L
Refrigerant Type: R134A
Ambient Temp: 85 deg
Pressure Low: low
Pressure High: low
Country of Origin: United States

I think I've come to the right place with my car HVAC issue. My high side schrader valve is leaking.

Cliff notes version:
Does anybody know the high side HVAC schrader valve on a USA based 5th generation (1998) Chevrolet Corvette?

I'm not a professional but a enthusiast working on my own car. I'm having trouble with my HVAC system Even worse it's going to be in the 90's (F) all week. I have some gauges that I used to recharge the system last year that display low and high pressure. I also have the Mastercool valve core remover that allows you to change the schrader valve without losing all the R134A.

It looks like this:

The only trouble is, it only worked on my low side. The high side has a much larger valve. I went to check the system pressure today and I could hear fizzling out of the high side HVAC, not to mention the charge is so low the meters don't even read (and no I have not been using the AC so I won't burn out the compressor). It's not totally empty as if I press on the valve it still makes sound.

Sooo, today I bought a universal double ended valve core tool from the local auto parts store, and tried to use the high sided schrader valves from a kit I had, and it was too small

I thought it may have been a "GM large bore" but then I read that was only used with R12s and in the 80s. Then I'm reading there's JRA (I think common in imports), EATON SSV (and apparently in different sizes too, 13 and 16mm) and some others. If I were to guess, I'd guess it's an EATON SSV 16mm like this:

or this one labeled as "GM R-12 & R-134a High Flow Schrader Valve Core (Primary Seal Type) W/ Neoprene Seal; OEM 5910609"

That way I can order the correct tool. The "stems" of the tool are (or just pay someone to change it out :lol: )

Any ideas?

Edited: Tue June 28, 2011 at 9:50 PM by eric w

mk378 on Wed June 29, 2011 10:23 AM User is offline

You don't need a fancy tool to change the valve now since the system is empty. Most shrader valves leak some, that's why there is an outer cap on the port. Most people who think their car's refrigerant is leaking out a shrader valve actually have a leak somewhere else. The GM compressors are prone to leak at the shaft seal. If it's a V5 or V7 compressor it's also common to leak at the case joints.

eric w on Wed June 29, 2011 12:20 PM User is offline

Makes sense- I now plan to put in some UV dye to recharge then get the UV kit. If I press the valve it does still "spirt" indicating there's a LITTLE left in the system, so the remaining positive pressure should keep the ambient air out (I would hope), so I don't have to get it vaccuumed. Either that or just take the car to a shop with the machine...

eric w on Wed June 29, 2011 8:42 PM User is offline

Alright it wasn't as serious as I had thought- I haven't used the meter tool in a while and forgot to screw down the valves that engage the schrader valve.. I did that and most of the readings checked OK although when running the high was kind of low. I went to the store, got a 12 oz can with the UV dye in it, then filled it up. The AC works great now! I ran it for a few minutes and couldn't find any leaks just yet with the UV light but I'll keep checking the next few days. I have a feeling it was just low from the car being 13 years old. If I have to charge it once every 13 years, I'm doing pretty good haha. Hope the fix holds...

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