91 deville ac problem

Ricklh · #1 (**permalink**) 01-06-09, 05:43 PM

Can a 1991 deville with climate control be converted from r12 to 134a. i converted one after installing a new compressor,orfice,accumulator and flushing system. i can,t get the f12 code (ac temp. switch lowside error) to clear. if it can be converted how much 134a will it hold nd where is this temp. sensor located that the f12 code is talking about.

**Ranger** · #2 (**permalink**) 01-06-09, 08:13 PM

Sure it can be converted. Just like you did the other. The low side temperature sensor should be on the passengers side of the orifice tube I believe. Look for a coupler in the A/C line along the firewall. The orifice is at the coupler. Low pressure is on the passengers side of that. What I am saying is what I remember from my '97, but I think yours should be similar.

bklynsoulja · #3 (**permalink**) 01-06-09, 08:25 PM

can a 89 cadillac deville use r134a? i changed my compressor and drained out all the old r12 i believe and added like 4 cans of r134a and 1 can of r134a with oil or w.e. it was but after a week it was gone am i doin sumthin wrong?

Ricklh · #4 (**permalink**) 01-06-09, 09:16 PM

hey ranger, the only switch on the low side on this 91 deville is screwed into the accumulator. it looks like a low pressure switch. i see another switch just before the orfice tube but thats not the lowside.

**Ranger** · #5 (**permalink**) 01-06-09, 10:39 PM

Rick.
Then I'm not sure what to tell you without a FSM. Been a long time since I have seen a 4.9.

Quote:

can a 89 cadillac deville use r134a? i changed my compressor and drained out all the old r12 i believe and added like 4 cans of r134a and 1 can of r134a with oil or w.e. it was but after a week it was gone am i doin sumthin wrong?

NO! R134a cannot be used as is in an '89. R134a was not used until about '96 I think. YES, you are doing something wrong. There is more to a conversion than removing the R12 and replacing it with R134a. You must flush the R12 (ester) oil from all the lines and compressor. You have to replace the accumulator and condenser (because it is almost impossible to flush). The you have to add the appropriate amount of PAG150 oil to each component (accumulator, compressor and condenser I think).

bklynsoulja · #6 (**permalink**) 01-06-09, 10:59 PM

so if i do all those process il be good? or you think i should just go back to r12? if so how would i go back to r12 if i alrdy up in r134a when i just changed my compressor

**Ranger** · #7 (**permalink**) 01-06-09, 11:10 PM

You could just evacuate the system. but since you added R134a WITH oil, you now have a mix of oils. I think the system needs to be flushed. Better talk to an A/C shop and tell them what you did.

bklynsoulja · #8 (**permalink**) 01-07-09, 12:37 AM

i know i got to replace the accumulator after you change the compressor too but if im doing the flush do i got to change the condenser too? and sorry for taking your thread Ricklh lol

**Ranger** · #9 (**permalink**) 01-07-09, 12:36 PM

Yes. Old condensers had tubes that where serpentine like a snake and could be easily flushed. The newer ones are like a ladder so it is almost impossible to flush all the lateral lines. Gotta replace them from my understanding.

noahsdad · #10 (**permalink**) 01-07-09, 11:22 PM

Okay - Ricklh: Since you have a hard F12 code, the diagnostic process can be largely done within the onboard system. First step is to enter diagnostics, wait for codes to run and the FDC display to show .7.0

Next, depress and release the OUTSIDE TEMP button to enter the BCM data series. The FDC will display F.8.0 . Advance through the output channels by pushing the HI button until you get to P.2.8. Write down the number displayed and let me know what it is.

Ricklh · #11 (**permalink**) 01-08-09, 10:35 PM

1991 deville 4.9 with climate control. This is what i had to do to get the ac working. i converted over to 134a. flushed system, replaced accumulator and orfice tube. added 3oz. of pag 150 to compressor. i charged system with 134a but could not get the f12 code (temp. switch low side) to clear. i replaced the temp switch and recieved another code. it was an f11 (temp. switch high side) that would not clear. i replaced the high side temp switch. pulled vaccum and recharged. all codes are clear and ac is working. these temp switch messages are miss leading. they are not located on the suction side of the compressor. they are located on either side of the orfice tube.

**Ranger** · #12 (**permalink**) 01-08-09, 10:56 PM

One side of the orifice tube is the low side and the other is the high side.

bklynsoulja · #13 (**permalink**) 01-09-09, 01:38 AM

how hard is to replace my condenser? and everytime i turn on my a/c i hear a big motor sounds and also i feel my car shaking or vibrating as i turn it on, if i turn it off it gone what can that mean? i was thinking blower motor but i dont know anymore any thoughts?

chubbyranger · #14 (**permalink**) 01-09-09, 07:47 AM

Quote:

Originally Posted by bklynsoulja

how hard is to replace my condenser? and everytime i turn on my a/c i hear a big motor sounds and also i feel my car shaking or vibrating as i turn it on, if i turn it off it gone what can that mean? i was thinking blower motor but i dont know anymore any thoughts?

Between this symptom and the rough idle it may be time to check the ISC motor. Does the shake/vibration caused by the AC only happen at idle? If so your ISC may not be compensating for the extra compressor load, although with a load of R-134 in an R-12 system its a tough call. I'd turn the ISC adjuster out a couple turns and see if anything changes.