The heat is on the way and im working on my AC - PeachParts Mercedes-Benz Forum

1981_300sd · #1 03-12-2009, 12:13 PM

Next week we are supposed to be in the 90's already, and I am working on improving the cooling ability of my 240d.

Last year I had a new compressor installed, and the guy I bought it from charged it with 134a. I had a leak last year at the low port fitting, the port itself was leaking.

I identified the leak, and then researched the recharging. I was told that when the 134a is lost, the oil stays in the system - no oil is lost.

So I got some no-oil-added refrigerant and filled to the correct pressures. The system ran ok (didnt cool as good as I need but worked) but whenever I turned off the AC the compressor made a harsh noise - so I thought there must not have enough oil in the system - I added 2 oz of oil and it still made the noise, but was much more quiet after the oil charge.

This year I am going to put the enviro-safe industrial refrigerant in the system. The instructions say to just evacuate the old charge and refill with enviro-safe. Does not mention adding any oil.

So, I guess I am lost - is oil lost when evacuating the system? (I do not mean flushing, just simply when you de-pressure the system).

Thanks for any clarification you guys can provide.

leathermang · #2 03-12-2009, 12:21 PM

What is enviro-safe composed of ?

Why do you think that would be better than 134a ?

Oil loss with a leak depends on where the leak is... if at a low point oil can be lost.

Normal depressurizing and refilling does not affect the oil amount in the system enough to worry about. But since you may well have had oil loss .... as evidenced by adding oil affecting the noise you heard... the only way to be sure you have the correct amount of oil ( that I know of ) is to flush and measure what you put in.

tankowner · #3 03-12-2009, 12:33 PM

Quote:

Originally Posted by leathermang

Oil loss with a leak depends on where the leak is... if at a low point oil can be lost.

Normal depressurizing and refilling does not affect the oil amount in the system enough to worry about. But since you may well have had oil loss .... as evidenced by adding oil affecting the noise you heard... the only way to be sure you have the correct amount of oil ( that I know of ) is to flush and measure what you put in.

---> x2

I would probably flush/drain it out and refill so you are sure you have the correct amount in there. It will also give you the oppurtunity to vacuum down the system. If you had a leak you might have gotten moisture in there and that will eventually kill your new compressor. You should also replace the dryer if that wasn't part of the new compressor installation.

leathermang · #4 03-12-2009, 12:57 PM

The pros assume that a leak means the system is corrupted... the cost of a new dryer/receiver is cheap insurance.
If the system is opened up at all a new receiver/dryer is called for. Also, it is the last thing to be put on the system before the vacuum is applied... and the cap should not be opened more than seconds before installation... it has moisture attracting stuff inside which is under oil.. so there is no way to take that out by vacuuming once it captures moisture....

tdelaurier · #5 03-12-2009, 02:45 PM

Quote:

Originally Posted by 1981_300sd

This year I am going to put the enviro-safe industrial refrigerant in the system. The instructions say to just evacuate the old charge and refill with enviro-safe. Does not mention adding any oil.

Be careful - some people will give you a hard time about using this stuff as a refrigerant.

To answer your question though - its hard to say how much oil you have in your system... You wont know if its the right amount unless you add it yourself. Which means a flush.

Im actually going to do the same thing this weekend - however Im going to flush the system, put on a new drier/receiver and a new expansion valve and then add the oil charge after I pull a vac on the system. Im hoping for snowballs out the vents when Im through. Its HOT here in Texas... well actually today its 40 but its gonna get hot soon...

leathermang · #6 03-12-2009, 03:16 PM

Quote:

Originally Posted by tdelaurier

Be careful - some people will give you a hard time about using this stuff as a refrigerant.

Like the POLICE ?

Hydrocarbon refrigerants are illegal in automobiles in Texas.

Like any local AC service people ?

If you are ever in need of someone else doing anything to your AC system and have a nonstandard ( not R12 or R134a ) in your system you may have trouble finding someone who has the equipment to do it.

Try calling locally and see what AC service people say...

Of course all us DIY guys think we can do all the stuff ourselves and will never get caught out on a trip needing someone else to get us cool enough to continue the adventure.

1981_300sd · #7 03-12-2009, 06:00 PM

I have been told very good things about enviro-safe. Yes it is a hydrocarbon, and it only requires about 1/3 the amount of r12.

The leak was because of a crack in the cap and the shrader valve (spelling?) was stuck down a little too. Finally found that when I got a new cap it stopped leaking, then replaced the valve. The system was never fully empty or exposed, it was a very slow leak.

I plan on charging with this stuff, tinting the windows as dark as legal, and see how that works. In the summer here, if I leave the car out in the sun for more than half an hour, its going to be a crappy ride - I hope to at least semi-fix this.

That makes sense with the responses I received. I bet some of the oil was lost when evacuated, and then I just added a can of 134 without oil, causing it to be a little low. Probably damaged the compressor some

Since my original post I went ahead and ordered some cans of the enviro-safe. With my order I got some cool oil testers - you just screw them into your low port, have your compressor running for 10 min, push this button, and it tests your oil. Tells you if you have enough or are low, and also tells you the condition of the oil... pretty cool!

What do you think?

http://www.es-refrigerants.com/products/w/id/166/t/pittstop-r134a-oil-checker/details.asp

leathermang · #8 03-12-2009, 06:20 PM

You say you are going to charge with enviro-safe...
but post an oil checker url calibrated for R134a ?
and ask what we think ?
Your whole situation is a recipe for disaster in my opinion. There are a huge number of threads concerning this subject. You did not say which state you live in... might want to check that before installing it... several states have made hydrocarbons illegal for automobiles.... why just automobiles in some states ? Because stationary units for buildings are not moving around at 70 mph with the hydrocarbon under pressure and up in front of the bumper...If you use it in a state where it is illegal ... and you have a fire which can be even vaguely attributed to it by some slick lawyer you are going to be liable for resultant damages... just not worth the small if any initial savings in charge cost... and this does not even address the oil miscibility issues which are so important on our type ( R4) compressors which have NO OIL SUMP ( unlike the old York, or newer swashplate type compressors )...meaning that all the lubrication for your compressor comes from the oil being carried in the refrigerant vapor....
I hope you go ahead and use the enviro-safe... I am writing this for others reading this thread....

tdelaurier · #9 03-12-2009, 07:21 PM

Oh please - illegal??? So is exceeding the speed limit - those who live in glass houses........!!! Like the cops are gonna bust you for envirosafe in your A/C system - I laugh in your general direction (to quote Monty Python) Like a cop would even know to check such a thing. How ridculous. If it cools use it. Plus show me the state law that says its illegal in Texas. Now back to the subject at hand....
Use the test strips and charge as necessary and ignore the people who say its illegal and talk about lawyers. Enjoy the cold air. Make sure you get legal tint - someone might bust you for it if you dont!

JimmyL · #10 03-12-2009, 09:31 PM

RLeo and Knightrider966 have installed the Envirosafe and are very pleased with the results. Others have also but I don't remember their forum ID's at the moment.
I have several cans myself out in the garage, and I imagine this is the summer that China goes from R134a to Envirosafe. I'm guessing I will do a flush of evap and condenser since I have no baseline on the oil situation. You don't have to worry about moisture with the Envirosafe as it doesn't "turn acidic" like other freons in the presence of moisture.
Nothing quite like the testimonials of folks who are currently using the product and are very pleased with the performance.

BTW Thomas, while Leathermang will I'm sure carpet bomb you with very correct facts, and is perfectly capable of taking up for himself, there was still very little if any reason for your condescending reply. He's forgot more than either of us will ever know and is just a stickler for propriety and factual data.
{now if we could just get him off dial-up, and get him to apply these AC principles to his 240D}

tdelaurier · #11 03-12-2009, 09:44 PM

Quote:

Originally Posted by JimmyL

BTW Thomas, while Leathermang will I'm sure carpet bomb you with very correct facts, and is perfectly capable of taking up for himself, there was still very little if any reason for your condescending reply. He's forgot more than either of us will ever know and is just a stickler for propriety and factual data.
{now if we could just get him off dial-up, and get him to apply these AC principles to his 240D}

Im sure he does - and I didnt intend to be condescending - I meant more to be a smart a** than anything. I've gained soooo much knowledge from people like you and leathemang I have the upmost respect for people who have paved the way for me. I just find it funny when people say things are illegal and therefore you should do it.. My bad - noted - JimmyL

tankowner · #12 03-12-2009, 09:47 PM

Enviro-safe, hmmmm . . . interesting website. Well, it's endorsed by GreenPeace so it must be good, right? And it smells like pine . . . for leak detection they say. Ah heck, I say put it in and see how well it works.

The PittStop oil testers look like they should be sold by Billy Mays.

You can use those if you like, but your taking a chance with your new compressor and from the sounds of it, it might already be suffering. If you really want to be on the safe side and not risk your compressor - do as suggested - flush your system, vacuum down, replace dryer, and then recharge with oil. Otherwise you just don't know and you'll be singing the blues with a bum compressor. On the up side, your bum compressor will smell like pine.

JimmyL · #13 03-12-2009, 09:53 PM

Quote:

Originally Posted by tdelaurier

I've gained soooo much knowledge from people like you and leathemang I have the upmost respect for people who have paved the way for me.

UH OH!!!

Now you've done it!!!

I don't deserve to be put into the same category as him as far as imparting knowledge. Now, when it comes to the finer points of sarcasm then I can more than hold my own.....

No worries Thomas. Good excuse for forum banter......

Matt L · #14 03-13-2009, 11:37 AM

It does sound like you have fulfilled the legal requirements for using hydrocarbons, unless it is locally prohibited. However, PLEASE label the system VERY well to indicate the contents. You could save a future serviceman a lot of headache and money.

What oil should you use with ES? If I recall correctly, it works with POE or PAG but prefers good old mineral oil. Thus the two-step conversion process is really bad for running hydrocarbons.

I would flush the system and replace the oil with mineral oil to use hydrocarbons. You will be a lot happier in the end. (Of course, I would stick with R12 or R134a though.)

leathermang · #15 03-13-2009, 12:10 PM

Matt L , Good post, Thanks.