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What about the SIght Glass???? Is he installing one of those???? They're only about $6 to $15. The site glass will GIVE YOU some VERY EZ diagnostics capability.

Yes, keep us posted on yuour prgress when ever u feel like it.

Edit: If the mechanic gives u some static over the site glass and u win then make sure that the site glass is mounted in a REASONABLE location for viewing. i.e. NOT mounted in some location that is not REASONABLY easily accessible for viewing.

I was told that sight glass units are not used for R134. Indeed, vintage air does not offer them. We have not installed as yet, so could add it if it really is viable.

Does anyone have one on a 134 system....and does it help?

There are differing opinions on the sight glass. For R12, they are useful but on R134 it's a question.http://www.refrigeration-engineer.com/forums/archive/index.php/t-6617.html It won't hurt to add one if it's available and some come built into the receiver/drier. That is probably about the only relatively easy way to do it today but that type drier doesn't typically come with the kits. I don't recall seeing sight glass units at the usual sites that can add inline using the typical beadlock and Oring barrier hose fittings used by most aftermarket systems. Undoubtedly, they are around somewhere. For myself, I don't think I would trust the older flare type fittings on most units that would be more commonly available. I'd be concerned those would leak long term with R134 and it's smaller molecules.

quote:
"I was told that sight glass units are not used for R134."

Oh yeah. Ok BUT WHY NOT!!!! I can imagine the double talk u'll get for an answer. Such as: "because no production vehicle currently uses them".

Bottom line: What kind of PROBLEMS will a site glass cause when used with the R134????? Need A SPECIFIC TECHNICAL answer in terms of any problem the site glass mite cause.

I read the link that HH56 provided above. Note that there is a split opinion on the site glass issue but the opposition gives no technical reasons other than charging/service issue which is even to some degree argued with by the other side. If that doesn;t mean anything to anyone then just get out there w/broken down AC unit on the side of the hiway 100 miles from home with the house mouse in 100 degree weather and find out what it means. Usualy u can find some 'buy-here pay here' car lot that will put a can in it for u watching the site glass for about $20 and be on your merry way. Get the picture??? There is lot i could say about this but i won't bore anyone anymore with it.

I recommend the site glass not necessarily (but also possibly) for charging and service final decisions but rather for PRELIMINARY EASY diagnostics.

THE IDEA is to watch the site glass on various conveninet occasions when the system is operating in an optimal manner.
Watch the site glass and become familiar with how it looks when it is operation to satisfaction. THEN if problems begin to arise the site glass in most cases (tho not necessarily) will an indication of the problem.

The idea is to use the site glass as, at the very least, diagnostics.

quote:
"Does anyone have one on a 134 system....and does it help?"

Yes. I do. on 3hree diferent vehicles.
The 56 Executive is an R12 system converted to R134. The site glass was on the reciever (usual place) and i charged it according to the site glass.It has ran fine for over 8 years. However, i had to change the reciever about 5 years ago and the replacement did not have a site glass. I sure bitched about that to the parts store. In my haste (house mouse bitching at me) i did not install an independent site glass and have kicked myself numerous times ever since.

Car2: 88 Ranger wit hdealer installed AC. I have owned and driven this truck DAILY every year for the last TWENTY TWO years and 180K+ miles. Original R12 with site glass BUT USING R134A for over 10 years now.. THis is a FACTORY SUPPLIED dealer installed system that has NEVER been opened except once to replace a service port core. I diagnose and charge by SITE GLASS. It sure keeps my 190 pound ass cool all summer. I've ran everything in it, R12,R134a and Freeze12. R134A and Freeze12 are sold here in Tn at local dollar stores, walmart etc.

Car 3. 73 impala (sold in 2008) owned and driven almost daily for 35 years. Had factory R12 sytem wit hsite glass and later used r134a and freeze12 using site glass for diagnostics and charging.

I'm tired of typing.

The sight glass units may be more extinct than I thought. I didn't find any at the usual sites I buy from except this one flare fitting from Old Air.http://www.oldairproducts.com/catalog/hoses-tubes-fittings/91-2670/sightglass-p-3914.html Even the built in receiver units have somewhat dried up. Used to find several sight glass receivers in various sizes and at least a weld-on sight glass at each place- Limited availability and maybe special order things now.

For myself, I am not adding one to the system I am building because I didn't find any with Oring connections. I probably would if I could since there was one originally, the controversy over whether they work well with R134 aside. I just don't trust the flare to O ring adapters but that is me and those are available. PV8 probably has flare fittings and no difficulties on his cars so that is an option.

Had thought about using the original Packard sight glass since I had it but that requires soldering to copper and copper Oring fittings appear not available. I am using a combination of pre-made length aluminum tubing with end fittings and hoses so will not be able to attach it.

O-rings:
My 56 Exec has a gerry rigged AC system composed of ca. 1958 Mark IV evap, 84'ish (R12) toyota pump and condensor and lines and one or two home grown line connexions.

SO it definately has o-rings and i remeber buying new o-rings upon assembly. That was some 8 or more like 10 years ago maybe. Upon intial charging i used a R134 'conversion kit' and have ran the R134a ever since except for one time topping off with 1 canof freeze 12. I've checked it twice about 5 years ago with two different leak detector systems borrowed from AZO and AAP. NO line leaks. Therefore, in my case, i can not find any reason to fault o-rings used with R134A.

edit: Ditto for the 88 ranger and the 73 chevy on the o-ring/R134A compatability.

Therefore, in my case, i can not find any reason to fault o-rings used with R134A.

Agreed. That is why I am trying to stick with O rings. The rubber adds a bit of surface and works with imperfections. Even the early versions of O rings. My issue is with the flare fittings that was still used and common up until the 90's and beyond. One microscopic flaw or bit of something on a surface and you have a leak. 134 is much more prone to leak than 12 because of the smaller molecule.

eBay search "sight glass" 515 results. I didn't look at them real close. There is one very intersting manifold gauge WITH a site glass.

Site glass 'not needed for R134A' Hmmmmmmm. well just check this out:

http://cgi.ebay.com/Single-Manifold-Ball-Valve-Type-Gauge-Sight-Glass-/300533982306?pt=LH_DefaultDomain_0&hash=item45f938a462