Should I be adding compressor oil with my refrigerant?
 

Starting to get warm outside here and doing my summer tasks.

My low side cap was a little loose, so I tightened it - and it snapped off. The little plug from the cap was stuck inside pushing down on the valve, slowly leaking my r-134 out. Not much I could do because the plastic piece was stuck inside the valve, and could not remove the r-12 to r-134 conversion piece.

It was a very slow leak, and once out I put a new adapter right back on. I could not see any traces of oil leaking anywhere.

So now when I refill, should I put just plain r-134 in since it was a slow leak out and no oil appears lost, or does oil somehow get carried out of the system when leaking?

Thanks for your input!

It all depends, as the oil does leak out with the freon. Without knowing how much you lost it can be a gamble. You also need to know which oil is in in there, IIRC there are two types, PAG and Ester. Oil charges do come in 2 oz shots, and you can buy freon/oil mixes. Do not use the stop leak or freon w/stop leak.

Have you guys tried using the "oil checker things"? I saw some for sale online somewhere recently. It was a little piece that screws on to the fitting and based on the color, you add oil.

I was wondering how reliable they are since there is no way to really tell exactly how much is in there.

I have never seen anything mentioned in any AC forum or book which would suggest that the color of the oil in the AC system might correlate to the amount of oil... or the need for oil in the system...
The only way I have ever seen anyone say the correct amount of oil in an AC system could be determined was to flush the system and measure the amount put into it.
A PAIN, YES, but the only reliable method I have ever heard of.
And you do NOT want to over fill any more than you want to be low...
If the leak was at a high point in the system...and you saw no oil smudge at that location and you know you had the correct amount before the incident I would not add any.

Ok...... I should have been more specific. Here you go:

http://www.autorefrigerants.us/PITTSTOP.htm

They have these for R12 and R143a.

Looks like it may only apply to ' Enviro-Safe' junk refrigerant.

Another link:

http://cgi.ebay.com/ebaymotors/R12-A-C-Refrigerant-Freon-Oil-Checker-Tester-10-pack_W0QQcmdZViewItemQQhashZitem5190a6be33QQitemZ350319197747QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories

Seems to me that this would be better than either not knowing or having to drain and fill from scratch. Especially for those that are automotive A/C challenged.

I'm curious if anyone has used them?

People who are ' automotive A/C challenged' should be taking their automobiles to experienced A/C mechanics to get their work done...
Using a bogus piece of test equipment to potentially give them a false sense of security is the last thing a person needs.

IT ' Seems better to you' because you have not done enough automotive or general HVAC research to make an informed opinion.

In a perfect world that would be great. I'm sure the reason most people try to work on the own A/C is for fear of being ripped off.

So, with your vast knowledge, you are familiar with and have had bad luck with this product? Do you have the proof to back up your claims?



I have been servicing A/C systems for over 25 years and have never had a problem. Maybe you should read the above post a little closer. Looks like you are the one that needs to do the research!:D

I agree with this.
Whether or not a test strip or device can tell what oil is in there is not my fight. I'd want to knnow what oil is in there, and then how much of it is in there. No worries on topping it up, I'd still want to know how much is in there, so Im not under or over-filled.

Regardless, I'd take it to a shop to recover what is left and then pull a vacuum on the system for a long time. If it is completely flat, with an open valve, and has been for a while, id actually replace the receiver dryer as it may be saturated.

Then you can meter the right weight of refrigerant in, and be all correct...

With you suggesting you have 25 years experience with AC stuff... you tell us what chemical or physics rule you think would cause the COLOR of the oil in the AC system to accurately indicate the relative charge condition.

Ever seen ANYONE who is not SELLING these things suggest they might work ?

Did they do blind test with random cars, and after the test, did they open the systems and recover the oil amd measure the quantity, and compare it with the results obtained by "tester"?

I do not have many years of A/C experience but I have yet to fail to fix/convert an A/C system on all the cars I had/have. If it were my car, I would just go and buy the 'high mileage' R134a and be done with it. They have oil in the can. Alternately, one can buy a 2 oz can and charge it, then follow by the normal plain r134a.

Unless it is a brand new car or new system, how can one maintain a precise mix? Or what is a correct mix for that matter? It will always be a best effort approach IMHO.

He already has 134a in his system so we are not talking about converting back as far as I have read.

I do not know what you mean by ' high mileage' R134a .

They do not have oil in the can automatically. You can buy the cans either way.

Keeping the system from leaking if you already have it correct is the only way to maintain the mix and charge in the correct range.

The correct " MIX" is not the criteria we have to work with.

Each system has a total volume of refrigerant and needs a certain ratio of oil to keep the system lubricating the compressor... Both the total refrigerant and the number of ounces of oil information will be provided by the automobile manufacturer.

If you were making up your own system then you would use the working pressures for the refrigerant charge and then add an amount of oil which was used on other systems of about the same amount of refrigerant as you wound up putting into yours ( a little at a time until the pressures were in the correct range)
Warning.... doing the refrigerant by working pressures means going slow... adding a few ounces at a time when guessing you are getting close to the final amount...
AND MAKING SURE YOU HAVE THE TEST SITUATION CORRECT... WHICH IN MY RESEARCH WILL MOST LIKELY REQUIRE A SQUIRREL CAGE FAN MOUNTED IN FRONT OF THE CONDENSOR WHILE YOU ARE slowly ( stabilizing for 15 minutes per few ounces of charge increase ).. INCHING UP THE CHARGE...
Do this outside of course so the CARBON MONOXIDE does not kill you.

Some shops, Walmart included, sells a r134a can for 'high mileage' car. Basically, oil is mixed into the r134a already.