dnwong

I bought a can of PAG 46 oil.

http://shop.advanceautoparts.com/p/i...2Fc+oil+pag+46

I tried using the manifold gauges and the system does not suck it in after running for 20 mins.

Am I missing something?

Noahs944

Usually when the system is in vacuum mode then apply to the hi pressure side. In a shop environment with shop tools anyhow.

harveyf

There are a ton of posts regarding A/C systems that you should review. Not sure why you are adding just oil but that's your call.

I made the following mistake once and share this with you. Study your various connections. There will be the ones on the car with Schrader valves (little stems in the middle of the connector) that must be depressed to "open" the connection. The R134 hose connectors have a dual function. The first is that the outer sleeve is slid back, then you 2 hand it over the fitting on the car, and release the sleeve. This locks the fitting from the hose onto the fitting of the car. (Little spring loaded ***** on the connector engage a groove on the fitting on the car). This action can sometimes be a bitch to achieve and you must verify that you got the thing fully attached or the next step won't work right. The next step: There is a **** on the hose fitting that you must rotate clockwise (righty tighty, lefty loosie!) which depresses the Schrader valve inside the fitting and thus opens the circuit to pass through the R134 or the oil. If you forget this step, nothing happens. This might be your problem. Under normal circumstances, the can should empty in minutes, if not seconds.

If you are using a set of manifold guages, make sure you understand how the valves work on the guages. Not complicated but there will be at least one valve on the guage that needs to be opened.

FYI, the above assumes your car has the R134 fittings, based on the link to the oil that you provided. The orginal R12 fittings are different and simpler. On these the Schrader valve is depressed when you screw the hose fitting down tight.

dnwong

Yep. done all that. I had vacuum the system out and added new Freon. Pressures are fine. 20-30 on the low and 150 on the high. My concern was since I vac the system, it might be low on oil, so I wanted to put an 1oz back in just in case. But the oil does not seem to get sucked into the system like way the freon did. When I open the can, the pressure on the low side gauge went to 80. So, there should be enough to get it into the low side at 30.

CO951

It should be the exact process you used to add the Freon. I assume you are using a standard manifold, you hook the can to the center hose and you have to open the low side valve for that to get to the low side gauge. If the low side gauge goes to 80 when you open the can and it stays there that says the low side manifold gauge is open, but it's not able to get to the low side. (To me this sounds like the Schrader valve at the connecter isn't opening.) When you first connect the manifold (before opening the low side manifold valve) did you see the 20-30 on the low side gauge, so that you know it is properly connected.

harveyf

Well, now I understand a little better why you want to add oil. I am just going through all this on my 928 and there are some good discussions on that forum about when and how to add oil. For instance, on a brand new 928 system you add 12 oz of oil. That value gets reduced depending on the nature of the various repairs, as the oil is contained/distributed throughout the various parts of the system. Sounds like you are adding the 1 oz as a precaution. No problem there. I agree with CO951, it should be the same process as adding the freon so nothing is jumping out at me to offer any further advice. Just the obivous physics stuff: The pressure in the can has to be greater than that in the system and all the various valves need to be open. It's just a fluid transfer problem