Urgent Need Help On A/c System

[914lps]

My A/C is out. I have a leak in the system. It is small, but I need
to fix it.

After researching I have decided to convert to 134A. My research was reading
posts online, and calling about 6 repair places in major cities to see what
they recommended I'm in a rural area.

So first I convert the system. Fill with 134a and then look for the
hard to find leak.

I took the car to my “regular” mechanic.
He is a good guy and is honest.
But I am the only customer around with a Lexus. In fact to find a guy that “works” on Lexus
day in and day out, it is a 150 mile trip.

Anyway he is working on it. Or trying
to… His plane is to evacuate the system,
flush it, change the fittings, replace the dryer, etc, and then fill with 134a
and oil, and UV dye.

He is having a hard time figuring out how to get to the parts he needs to
get to as the Lexus routing of stuff is different. So I am looking for any diagrams or tutorials
I can find.

Anyone know of any????

If needed it is a1991 Lexus LS400.

I did some Googling and Bing'ing, and forum searches, but today just has not been my day.

In particular he needs any directions on retrofitting this A/C system, how
to get into the system. What of the four service ports are for what (which
ones does he connect to for charging, gauges flushing, and so on) , how to
flush the lines and drain compressor, best way to clean evaporator and dealing
with the expansion valve (replace it or clean it and how to clean) on the fire
wall.

As always I thank you folks.

Oh I told him I would take my time to research it etc.. My time is cheeper then his.... :P

[1990LS400]

A $15 2-day subscription to https://techinfo.toyota.com/ might provide some useful information. I don't think it will include information about the conversion which I would have thought would have come with the conversion kit like it did with the conversion kit for my 90 LS400 over 10 years.

Maybe you will also find some help at http://www.lexls.com/tutorials/air/

[914lps]

One of the first places I looked was over at Lexis.com. Good guy, but did not have what I needed. I will stop over at techinfo to see what I can see, but I believeI need more then diograms and parts ID. I need directions. Got to be on the web someplace.....

[landar]

My son just made the conversion from R12 on his 92 LS400 this Spring(should be the same as your 91). Did it all on his own with no help from me. He had to buy a new dryer, vacuum out the entire system(rent vacuum pump from Autozone), new R134 fittings, new O-ring seals (his was leaking at the compressor fittings). Installed a few cans of R134a, oil and thats it, I believe. It now works great. You could do it yourself I will bet. I will quiz him when he gets home about any sites he used or issues he had but I believe it was very simple.

[914lps]

I would love any info he can give. At one time I would have tried to do it myself, but these days my boddy does not like me doing those things...

I did do it myself when I had a 84 Saab. But that was a very long time ago, and a much simpler extreamly easy to get to system.

[914lps]

I went to https://techinfo.toyota.com/ and paid the 15.00 Nothing dead on for what I need. But printed outabout100 pages of stuff to take to the mechanic in the a.m.. If anyone has any info I would still appreciate it.

[landar]

I found out a bit more info about the conversion. You can google "How to convert R12 to R134a" and get a lot of similar advice.

Of course it stands to reason that if you have a leak, you should find and fix that soon, otherwise you will be forever adding refrigerant.

Remove the compressor fittings and unbolt the compressor because you are going to have to turn it upside down to allow any old oil to seep out. You do not have to remove the compressor from the engine bay but you will need to rotate it. New oil(several ounces) is added to the 'low' side and the compressor shaft rotated a few times to initially distribute inside.

After removing the old dryer and installing a new one(the new one has desiccant designed for R134), you pull a vacuum on the system for approx an hour or more. My son had gauges hooked up to the low and high side to monitor the vacuum. He removed the vacuum pump and left the gauges hooked up over night. In the morning, the vacuum was still there indicating that there was no leak (or very small). Thought that was a good test without wasting R134.

You will need fitting adapters to convert to the R134 standard and you can buy these at most auto stores.

Maybe yours is all done by now. Did your mechanic get it converted?

[914lps]

The issue "we" are having is flushing the system. Most ac systems you pull he compressor and drain the oil from the built in reserve. However Lexus uses a custom compressor that has no oil reserve in it.

"The system also has four pressure ports in it instead of two . Along with other unique to it things.

So "we" can not find information on how to properly flush the system correctly. And were the system has it's oil reserve, and the such.

I found directions from Lexus on how to do the conversion. However it simply says to flush the system. It does not say or give info on "how".

The system must be flushed of as much of the old oil as can be done. Leaving to much of the old iol is not a good thing.

[landar]

Well, you make a good point about flushing the system. It *should* be done thoroughly and I will bet that my son did not do everything 100% by the book. Even though the system is working well now, there could be complications down the road. Could be. But for now, he is enjoying cold air.

Having said that, it is also possible to lean too far toward the purist side and be frozen with fear that the conversion is not 100% correct. I would do the best you can at this time and call it a day. Just me. Do what you think is best.

[914lps]

I would say if it has been more then a month or two and he is having no issues then things should not be effected by the left over old oil.. But that is a guess on my part.