Automotive Air Conditioning Information Forum (Archives)

Old Codger on Tue August 12, 2008 6:41 PM

Year: 1995
Make: Toyota
Model: Camry
Engine Size: 4 cyl
Refrigerant Type: R134A
Ambient Temp: 97

I am beginning to get ready to fix the AC in my 1995 Toyota Camry 5SFE 4cyl. I bought the car used with the compressor chattering. I know that there are at least two different oils in the system. Initially the plastic cover of the magnetic clutch coil melted and it blew a fuse. I replaced it with a used coil, bearing and plate and it ran about another month before the same melt down occured. I am planning to replace the compressor with a new aftermarket compressor and clutch figuring the old compressor was dragging enough to build heat up in the clutch and melt the coil's plastic cover. I'm not sure what to expect when I open it up.

I envision pulling the evaporator and condenser out of the car and flushing them with lacquer thinner. I plan to fill them up and let them sit and then shake them up a bit while draining the thinner out of them and then trying to pop flush them with an air compressor and finally blowing each out with an air compressor (5 cfm at 40psi) for a period of time.

Does this sound feasible? I don’t have easy access to nitrogen but if it is important I might be able to finagle it.

Does anyone know if the 95 Camrys used serpentine units or parallel units? I understand that serpentine units can be flushed much more reliably.

When I open up the system and start flushing things out I anticipate that there won’t be any significant particles. I’m really just after the (possibly) incompatible oils and making sure that there is zero residual oil in the system. What might I see visually that might make me want to replace either the condenser or evaporator or the TXV (by the way, what does the “T” stand for in “expansion valve”???)

Is it important to follow the lacquer thinner flush with a made-for-ac-flush? I was going to try and get some flush from a near by NAPA store for the hoses, I guess that I could get more for the evaporator and condenser if it were important.

Is there any "recommended" time between flushing and pulling a vacuum? Here in Houston the humidity is generally 70% or higher so I have to believe that the system will be "wet" pretty quick.

The Toyota manual says to use “genuine Toyota R134a air conditioning oil ND-OIL 8”. Can someone translate this to what is sold at an auto parts store? Is this standard PAG oil? What “weight” is it?

I must admit that I am looking forward to this project. I have been reading many of the threads here and they have been very helpful. I hope that I don't wear out my welcome.


Thanks,
OC

johnboy123 on Tue August 12, 2008 8:55 PM

i prefer the pags instead of the esters - in your case pag46 - why remove the components from the vehicle- generally i flush from the compressor (in your case) through the line to where it would be disconnected from the receiver/drier. then through the line on the other side of the receiver/drier through the thermo expansion valve back through the line going to the compressor. by taking the receiver/drier out of the system you essentially have cut the system in half and flush each half at a time. the compressor will come with directions on the oil requirement - 2 oz for the condenser, 1 for the drier, 1 for the lines and 1 for the drier. good luck

Chick on Tue August 12, 2008 9:03 PM

This is the recommended flushing procedure, I would not flush thru an expansion device, you could flush junk into it causing problems down the line. Pag 46 is correct if it has a denso compressor.. Which I believe it does..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

TRB on Tue August 12, 2008 9:42 PM

In my opinion unless you have a closed loop flush system like the H1000. . You should never flush through an expansion valve. It's my belief you could leave behind traces of flushing agent which will break down the new oil and a compressor failure will follow. Best to flush each component separately. Hoses with filter or mufflers should not be flushed.

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Old Codger on Wed August 13, 2008 2:03 AM

Since I plan on removing the evaporator and condenser to flush them I figured on removing the TXV (thanks johnboy for providing the “Thermo”) and not flushing through it. I just don’t feel that I’ll get all the oil out from the bottom of either unit if I leave it in the car, even if the TXV wasn’t a concern.

I have been reading and re-reading the flushing procedure that you referenced Chick. That is what prompted several of my questions. I appreciate your points. I had come across a reference in FAQ section referring to the PAG 46 substitute but I wasn’t comfortable what the ND-OIL 8 actually was. From many of the other threads I guess I will go with a DEC PAG 46.

Tim, I definitely don’t have (and don’t foresee getting) an H1000. drool, I want to be first on the list if you need any DIY testers!). I am definitely trying to do a good job on a shoestring. I got half a dozen quotes for replacing my compressor and got estimates ranging from $700 to over $1000. I’m hoping that I can DIY for closer to $400 including a thorough flush (which was not in the other quotes).

The flushing procedure acknowledged either nitrogen or “dry” air which led to that question. My ignorance led to the “what might I see visually” residue question and the serpentine vs parallel questions as well as the acceptable delay between the flushing and pulling a vacuum question.

Thanks for the replies.
OC

Chick on Wed August 13, 2008 6:10 AM

"The flushing procedure acknowledged either nitrogen or “dry” air which led to that question. My ignorance led to the “what might I see visually” residue question and the serpentine vs parallel questions as well as the acceptable delay between the flushing and pulling a vacuum question. "
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Of course nitrogen is best, but not all DIY'ers have it, so air, and a LOT of it is usually needed. The most important thing would be to get all the flush out as any residual flush can degrade the new oil and lead to compressor failure down the road. So use a lot of air, dry as you can get it, but add back the drier last, and pull a deep vacuum, then pull it again, that will remove most of the moisture by boiling it off, any left the drier dissicant will take care of..Hope this helps..
PS: Check the parts listed for your car
right here... prices are right, and doing the work yourself will save you hundreds...Good luck

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

HECAT on Wed August 13, 2008 11:43 AM

Always late to the party...

Old, I think your plan is good; making sure the components are clean and dry is the goal. It may be more than required to remove them, but how can I question a plan to be this thorough.

Johnboy, I agree the system needs to be split in two and hoses can be used as part of the circuit to flush each heat exchanger circuit separately (rear air is another story). I also agree that you cannot flush through the compressor or the filter.

My testing has shown that the energy of a flushing process is negated when flushing through a TXV or Orifice, and solvent accumulates and becomes near impossible to remove with an air blow which is also negated by the orifice. Many of these devices also use a screen that will need to be cleaned and or removed for flushing.

The only product I have been able to show any success with is with a HFC refrigerant solvent that will suck up the oil like a sponge and can be recovered by vacuum, and even then we are still limiting the "velocity" component of the flushing process.

Tell me more (or come to the "automotive flushing forum" page) about the chemicals, methods, and procedures you use; and how you are addressing and overcoming the many other unique issues that come with flushing through the orifice.



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Old Codger on Wed August 13, 2008 12:23 PM

My bad, I had thought the Automotive Flushing Forum was for systems other than the AC system. I guess, that I will hop on over there next. There's just too much information on this gol darn internet! I would like to learn more about the HFC refrigerant solvent that you mentioned.

Thanks folks,
OC

HECAT on Wed August 13, 2008 1:04 PM

The product is Genesolv SF by Honeywell (HFC-245fa). We use this refrigerant in a closed loop flushing and recycling system called the H1000. There is a lot more info about these products at my web site (www.hecatinc.com) and it is available for purchase here at the forum sponsors site, just click on the AMA logo at the top of this page.

Many refrigerants of the past such as CFC-11, CFC-113, & HCFC-141b worked very well as an A/C system flush because of compatibility and evaporation. With the exception of some 141b stockpiles, they are all gone now.

Many OE's want to use the refrigerant that the system was designed for (R-134a or R-12) because this will eliminate residual and compatibility issues they do not want to deal with. However, the boiling point is too low, that makes these items difficult to keep as a liquid (gas will not flush out anything); and recovery equipment (can't just release these product can we) and their small orifice valves, will not allow for the kind of flow rates required to flood and produce effective results.

A lot more understanding of these principles can be read in the PDF attachment to the first post in the "Automotive Flushing Forum" page. As a matter of fact, if no one objects, I may just drag this entire flushing topic post over to that page.

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Old Codger on Wed August 13, 2008 6:49 PM

You are welcome to put this over to the new forum page from my perpesctive.

OC