A/c r12 and r134a system questions
 

This is jus a general question:

On a nippondenso a/c r12 compressor,there is a "relief valve" on the top of the compressor...now,just that ,it releases excessive pressure on the system so ur o-rings or other stuff doesnt blow,but if it releases freon...out into the atmosphere it goes and corrodes my ozone area!!! Right???..now, if it was plugged up and the system was over pressurized it would blow ur o-rings...so basically it prevents blowing of o-rings and lines..correct???

Nippondenso r134a compressor system...no relief valve on top of the compressor..so no failsafe here ...alias...blow my system and replace the o-rings and or lines,...sorry for the retarded questions..but is this it in a nut shell..thanks

:think:


I'm lost...

lol


my AC experience goes as far as checking the pressure in my already converted to 134a system in my 91

I added a can of freon Monday, and it blows ice cold again :D 1st time I've have to touch it in 2 1/2 years



:cheers:

I guess i jus wanted to understand the purpose of this relief valve on the r12 compressor,and the purpose of not having one on the newer r134a compressor

My friend has a 92 runner and it's not the 134A. I was gonna charge his system for him til I noticed the charge port was different. So I looked at oriellys to check prices on the r12 (equivalent) refrigerant and found they also have r22.
So my question is are these trucks r12 or r22 and what's the difference?
Also the charging port is the one with the black cap (lower pipe) and not the red cap (upper pipe) right?

There is no presure relief valve on any a/c compressor, the a/c system is a sealed system and the only possible way for freon to escape the system is through a leak some were in the a/c system.

the two ports are for high and low pressure. these ports are for connecting a manifold gauge set to check both pressures and for adding freon. you can get a kit to change from r 12 to 134a. i think r22 is for home use.

R22 is more for commercial use, older car and home refrigerators used R12, but all newer vehicles and home refrigerators now use 134A. You can convert older cars from R12 to 134A, but you have to completely flush the R12 system and remove the oil and replace it with a new type of oil that will work with the 134A. Your better off with the R12 freon that originally came in the a/c system, it gets colder than the 134A freon.

not sure of the answer to the op but there definately are pressure relief devices on a/c compressors. It allows pressure to be discharged if the system goes over a set value.For example your ac clutch relay gets stuck closed and your comp is running continuously without your interior fan running the pressure in the system will eventually exceed this value and blow out all of your freon to the atmosphere. The reliefs that i have seen are one time use and must be replaced if they blow. My 90 3vze r12 comp does have the relief , I haven't worked on a toyota r134a system but other car makers r134a comps have reliefs.

Ive seen many toyota a/c compressors and they don`t have a presure relief valve on them. If your a/c clutch was to get stuck closed and the compressor is running continuously with out the interior fan on, nothing would happen, you just wouldn`t have any cold air blowing on you because the fan is off, there is no way the system could exceed any presure above the normal range is the interior was not running.

the example i gave was a situation that happened to me and while sitting at a stop light smoke started pouring out from under the hood then no more a/c. This is how i learned about this relief device.this was what happened to me and replacing the relay and the relief device then recharge fixed the prob here is a picture with it circled in red

Do you have a better picture of the part you have circled ?, what did that a/c compressor come off of ?.

sorry that was just a quick reference picture I grabbed off ebay that was for a 3vze. I will try to take a better picture of my spare 3vze comp tommorrow.

The more I try to learn about a/c systems the less I know. Not bashing anyone, lord knows that I appreciate all the help that this community has given me over the past couple of years. Saved me tons of money and saved my little honey of a truck from the Obama rolling turd program. But, when in comes to a/c systems, I have heard so many conflicting reports that my head in now spinning.

As I would say to my students tring to understand Kirchoff's Law, Be strong little camper, it will all become clear someday, I hope.