Help to ck AC for leaks - Atlanta?? - Page 5 - PeachParts Mercedes-Benz Forum

tyl604 · #61 09-03-2016, 07:45 PM

I have three 1lb cans of Freon. A friend has a set of gauges. So you think I should put say a half can in, stop, then listen for a leak. Could the leak be loud enough that you could actually hear it over the sweet sounds of the diesel engine?

If you will reread the "history" post you will see that I filled it up completely about four years ago, drove it home. But it did not cool very well and mysteriously the engine got way hot - almost into the red - on the way home. So much that I had to turn on the heater and dump some heat. Has never happened even once before or since. Do not see what adding freon could have to do with it almost overheating.

Watching UGA play NC now so distracted.

leathermang · #62 09-03-2016, 09:56 PM

I have no idea why your car might have overheated that time... sometimes single random events do happen ... perhaps a thermostat stuck ... a wild guess..

On the ' hearing the leak '.. no ... certainly would not risk R12 on that kind of attempt.
The blower motor pushing air across the evaporator would drown out that small sound.

It did not cool very well on the way home..

but after that... did it do ok for a certain amount of time ?

If it did not ever cool properly in this amount of time... then it is even more important that you start with the basics and be sure everything it up to snuff as you go...

Since you are the original owner.... can you describe over the life of the car the periods which it did cool properly ? Have you ever cleaned the fins on the evaporator ?

tyl604 · #63 09-03-2016, 10:04 PM

Wow; let me think. AC went out and was replaced maybe 2000; I bought a unit and replaced it myself. Took it to the indy and he vac'd it out and put in freon. Worked for years perfectly just like new. Maybe 2010 it stopped putting out cold air and I saw bubbles in the sight glass. Went to a forum member who had gauges and freon. We installed the exact pressure of freon at the forum member's house but it did not cool nearly as much as it always did before. I decided not to have him add more freon even though we discussed it - considered a bit more because it was not really cooling much. Will take a look at the fins; have never thought about cleaning them.

As best I can remember it never cooled very well after I put in that freon and then about four months later came winter. Did not use the AC for a while. The next late spring probably it had run out of freon. I have not added any freon since.

leathermang · #64 09-03-2016, 10:14 PM

So, What exactly did you do or not do when you replaced that ' unit ' ?
did you flush the old oil out ?
Yall installed the exact amount according to pressures.... or you measured the amount of R12 installed ?
Excess oil can degrade the cooling of the system....
the fins on the evaporator usually get bad slowly over time ( do you have a dog ) ... but if they are dirty... and you should look at some of the latest pictures of how bad they can be... then if you got too much oil in the system... the combo can result in less than OK cooling...

tyl604 · #65 09-03-2016, 10:27 PM

Replaced the AC and the receiver dryer. No idea about oil; the indy charged the unit up and it cooled like new for years. Then it ran out of freon; over what period of time I do not remember. Waited some four years then...with the forum member, we put the gauges on and installed freon until the pressure came up to speed. We were running the AC (as I remember) on full blast and max cool and I was holding it at a fast idle. It just did not get very cool and we stopped adding freon per the gauges. Never added more oil after I put in the new AC in about 2000.

No dog.

leathermang · #66 09-03-2016, 10:32 PM

So you , as far as you know, did not address the oil in the system... one way or the other ?
Add new oil ? put new receiver on ? that sort of structural stuff ?
Stopped ' per the gauges ' ... do you remember what the pressures were ?

tyl604 · #67 09-03-2016, 10:45 PM

Do not remember pressures. Did nothing with oil. Replaced AC and receiver dryer 16 years ago.

I guess it is an R4 unit but was exactly what I had when I bought the diesel. It was a single unit that I just bolted in underneath the motor after dropping out the old AC; except for removing the belts, it was really easy. After that I thought I could do it again in about an hour or two - surprised how easy it was. Do not really remember where the receiver dryer went but I replaced it too as I remember. Worked for some ten years before freon ran out.

leathermang · #68 09-03-2016, 11:02 PM

Seems like in addition to finding that leak... that you need to do the usual ground up cleaning of the system...otherwise you do not have any way to determine how much oil you have in the inside.. the only way to fix that is to flush all the system and put in the correct type of new oil . I do not think from your questions that you were intending to do that.. but you have so may variables not known and the fact that it did not work well after the last R12 install...... I think you have more than just the R12 missing and a hole.
Have you read the AC thread in my signature ?

tyl604 · #69 09-03-2016, 11:15 PM

Yes, I have read most of it. Theoretical question - why would there not be the correct amount of oil if it ran ok for ten years and the only thing that has happened is that the freon leaked out?

So I am really back to post #1. Pressurize and look for a leak.

leathermang · #70 09-03-2016, 11:24 PM

One... .the leak could have taken oil out with it...
Two... you may have too much oil... since you did not blow up your compressor..
but have had deteriorated cooling performance...
yes... you are back to pressurize and find leak....
You could look at Funola's thread... he has been checking each item for leaks...
but rather than just replacing the leaking item... assuming it is a hose or something.... or the schraeder valve.... you should be looking at flushing the whole system AND replacing the receiver dryer... and adding freshly opened can of proper oil ... not just replacing the leaking item... as that would probably leave you in the exact same situation which you were in when the forum member helped you out ... I am assuming yall put the correct amount of R12 in...and it was there but not cooling properly.... and then you will have used your cans of R12 to boot..

AND any time you have a leak the standard procedure is to assume your refrigerant and the oil have been subjected to moisture.. thus even if your system has Exactly the correct amount of oil... it should be cleaned out at the same time the new receiver is installed..

tyl604 · #71 09-03-2016, 11:33 PM

Agree. Also all my AC hoses are original to 1981.

leathermang · #72 09-04-2016, 12:07 AM

LOL.....and YIKES.....

vstech · #73 09-04-2016, 02:11 PM

240... I'm sure you are very skilled. I am also sure your methods with ac work on many vehicles.

The original poster is requesting someone to perform a pressure leak test.

Please stop badgering him and everyone else with your insistance your way will work.

The 123/126 ac system is JUNK! Extremely undersized for the job in any us state with summer heat...

Doing ANYTHING to the system that even minutely reduces performance is a bad idea.

Dye will reduce performance.

134 will reduce performance.

Freeze12 is 134 plus additives...

R12 is the best choice for stock system performance of the ac system.

Nitrogen or CO2 is the best way to pressurize for a leak test.

vstech · #74 09-04-2016, 02:21 PM

I assure you... if you live in atlanta, drive a w126, and dont follow lmg's warnings... you will be disappointed in the performance of your ac!

Quote:

Originally Posted by funola

LG, it is tiring your insistence that the FSM, EPA and your way is the only way to do AC work. If I have this right, you learned what you know from a lot of reading and research 5 plus years ago, you do not work in HVAC/ MVAC. Things change and some of what you learned is outdated or not applicable anymore. This is a DIY forum and most of us are not mechanics or trained professionals. He is Tyler's mechanic with 30 years experience. I would like to hear what he has to say instead of you constantly bashing people down who has a different way/ idea than what you think is right. Guess who I will trust to work on my AC if I have a choice between you and him?

tyl604 · #75 09-04-2016, 03:52 PM

Agree. Entire SD is 100% stock. Do not want to change anything. (Except I am not running Michelins any longer.) The AC was always very good in Atlanta until it ran out of freon.

I am hoping that next week when the holiday goers come back to Atlanta, someone will help me out to pressurize and check the system.