Air conditioning hoses & oil

[Kep]

I have been reading up on flushing AC systems. Several sources mention not to flush AC hoses that have mufflers in them. A) Does anyone know if a 95 5SFE AC system has mufflers in its hoses? B) Just what is a "muffler" doing in a hose anyway???

Also, the Toyota manual is very specific that only "Toyota R134a air conditioning oil ND-OIL 8" be used. Can someone tell me why they are so picky and if this must be bought at Toyota?

Thanks,
Kep

[toyomoho]

????

ND-8 and Freon R134A are industry product names not Toyota specific products although no doubt Toyota sells them under their brand name.

The ND-oil 8 is a replacement for the oil used with Freon R12 in older systems. R134A replaced this in later systems as being more ozone friendly. Both the oil and the Freon should be available at auto parts stores.

[Eye8Pussies]

out of curiosity...what is a "flush"? I know that a/c systems are vacuumed....but flushed? is it with freon??

[toyomoho]

Flushing is supposed flush out all the debris in the system lines, etc. There are some actually flushing products but often R134A is used. A well equipped AC shop should have a flushing machine basically a machine having hoses that attach to each end of the system or item being flushed.

The issues is a compressor that has frozen often leaves debris in the system, typically where it builds up in at the expansion valve, condenser, receiver and in the lines. The components would be disconnected from their lines and replaced or flushed then connected.

Flushing is also a good idea when changing over from R12 to R134A as the lubricants are not compatible with each other.

[Kep]

It seems that flushing helps to remove debris like toyomoho mentioned and to dissolve and help remove any remaining oil. In my case I know that there are at least two kinds of oil in the system of the used Camry that I bought. I intend to remove both the evaporator and the condenser to flush/rinse them out. I haven't disconnected anything yet but I am hoping that there isn't any significant debris. I'll know later. Right now I'm just trying to prepare for the job. I'm not looking forward to pulling the evaporator (? the one in the cabin?) in the heat down here.

So is the ND8 oil different from the PAG oil that is typically recommended by r134a suppliers?

Once more, anyone know what a muffler is inside an air conditioning hose and whether or not a Camry has one?

Thanks toyomoho!

Kep

[toyomoho]

Apparently ND8 is PAG 46 oil. The oil tends to be referred to as just PAG.

Not sure if you can't just take out the expansion valve and clean or replace. Getting to the evaporator on a 1995 might be a pain and thought requrired taking out the dash.

There is flush solvent sold on the internet (autobarn) but it is very expensive.

Be sure to change the receiver/dryer as the desicent will be exhausted by all the moisture getting into the system once it is opened.

[Stillrunning]

Kep,I agree with toyomoho that removing the evaporator is not only difficult but probably not necessary. The two flanged a/c lines on the firewall look very difficult to get to not to mention the evaporator itself. There are two more flanged connections for the evaporator along the inner fender on the passenger side just behind the rad. I would break those if you want to flush. Also make sure you back flush. I doubt the evaporator received any compressor debris of significance and I would not pull it unless you are sure it needs service. Search the internet for flushing kits that are already pressurized and be careful what you flush with. I would also suggest you replace any o-rings in the connections that you can get access to as this would be a good time to make sure the the system is tight and stays leak free.

[Kep]

All good points. I need to get out and buy some parts. I should have a vacuum pump arranged today and I am fixing my air compressor tonight. (Ever notice how nothing works when you finally start a job that needs them?) I'll start reviewing my manuals and then dive in. I'll try to get some pictures along the way.

I believe that I am stuck with either cleaning or replacing the evaporator. I am certain that there are at least two oils in the system and I want them out before I put in a new compressor. Everything that I've read so far says that you can't flush through the expansion valve. I figure if I'm going ahead and removing the expansion valve then I may as well pull the evaporator so I can move it around while I clean it so I can get any residual oil out of the bottom. I may change my mind after I get to the expansion valve! Same goes for the condenser though it looks a lot easier to access.

I'm not really looking forward to this but the AC shops around here want about $1,000 just to replace the compressor and drier and that doesn't include thoroughly flushing the system, just blowing out the hoses. I just hope that when I open up the system that there isn't any debris in the system.

I've noticed than no one took me up on my inquiry about hose mufflers so I "presume" that we don't have them in a Toyota. I still can't quite conceive what they are.

Wish me luck,
Kep