Ssergio86

hello there. I recently bought a 92' SC400 in fairly good condition, but i am restoring or making those little things that don't work correctly, work.

my problem with the AC is, after converting to r134 the car will blow cold for only 5 minutes and then it will blow hot air.

So first I thought it was the AC compressor that was turning off so i bypassed it and made it work directly from the battery and it still hot air.

Also i checked the valve that switches from hot to cold air (water), i actuall plugged the hose that carries the hot water in to the dash to heat up the cabin...and nope!.

after a while i noticed the AC compressor would stop and go in like 30 second intervals and every time the compressor kicks in the RPM goes almost to the point of stalling the engine.....so my guess, and my question is.....is my compressor bad?...maybe it's jamming?...or is there another reason why this is happening?....please let me know...other wise I may have ot spend a ton of money on a new AC compressor that i don't know for sure is bad.

thanks again I hope to hear from u guys!!!..

1JZPWRD

iTrader: (59)

First, welcome to CL. I also have the same SC. I would say its the compressor. If you have bypassed everything and still only blows for 5 minutes, theres a problem. I would add some freon with some green dye, and whip out the ratard glasses and look for any leaks. Then go from there. If there seems to be no leaks, and still only blows for only a few minutes, then its in the dash. It was $$$ to have it replaced. If you find out its the compressor for sure, DO NOT buy a rebuilt or reman. compressor. Buy a new Nippo off of Ebay or from the dealer. It will save you headache. I know from experience. Good luck with your search and let us know what you find out.

Its also mandatory you post pictures of your SC, inside and out, since you just joined! J/K..

Again welcome to CL.

Photon440

iTrader: (3)

Are you sure there's the right amount of 134a in there? I had similar problems once with an overfilled system.

Ssergio86

Thanks for the welcoming message, I will post pictures of my SC400, and even the restoration process, when i have the time. to do so.

i am almost sure there is no leaks in the system because, it will blow really cold for 5 minutes, and then it will suddenly change. if it had a leak wouldn't it progressively start blowing hotter and hotter every time?. well mine doesn't

..do I have the right amount of R134?...well i have put 5 or 6 small containers, i started adding until I felt the temperature of the air was adequate.

so my problem may be in the dash? what do you mean? like the water radiator that is is in the dash or the climate controller?..i can get my hands on a complete dashboard and install it myself, but I would like to know in more detail what is the problem that normally comes from there....

thank you guys for the reply, i will keep you post it of the progress on my car. there is still a lot to be done to it. and since this is not the first automotive forum I've posted, I do love to keep a profile on my car.

where do I start that tread? here?

1JZPWRD

iTrader: (59)

I was talking about the evaporator core. If the leak is no where to be found, with dye, then it MAY BE in the dash behind the ABS system. This was where mine was leaking from. Once the mechanic removed the original one, he showed me in person the green dye seeping out of it. I also had to replace the receiver/dryer several times, due to having going through so many rebuilt/reman compressors. I would say its your compressor and/or your evaporator, and not your climate control.

Have you had a vaccum pull on it? How long did it stay?

lexdud

You added 5 or 6 small containers of R-134a to your system!?!?!?

Please report back on how many ounces of refrigerant these "small" containers had. An R-12 system will normally take approximately 80% of that capacity in R-134a. "Small" containers of R-134a are typically 12 ounces or so. If you added 5 to 6 cans ... you EASILY overfilled your system. 5/6 cans at 12 ounces each would mean you could have added 60 to 72 ounces of R-134a. That's WAYYYY too much. The R-12 capacity of the system is 2 pounds (32 ounces) so you should have added about 26 ounces of R-134a.

Also, please go into detail as to how you converted your R-12 system to R-134a as I may do this on my '93.

Thanks and report back ...

JustChill

iTrader: (9)

ooh..waaaaaay to much freon...you're overcharging ur system buddy

Ssergio86

ok i doubled checked an i put 4 containers each one 11 ounces so what I'm going to do is get some freon out until i can get the compressor to cease stopping.

question?...where is the evaporator core?

BiGEZ

iTrader: (24)

Too much freon as mentioned above. Evaproator core is behind the dash. Evacuate some of the freon.

Ssergio86

ok problem fixed. over filled. got the freon out until the compressor started working properly.!!!! ok so next in my to do list...

1. upper arms replcement
2 lower arms bushings