A/C troubleshooting advice

[clydeyb]

As you can tell from all the threads I've posted I have a lot of free time on my hands. :L

I have one more issue with the car I recently purchased that eventually I will have to resolve. The A/C doesn't blow cold. Well its winter and not really needed right now but I would like to troubleshoot it if I can over this holiday period while I have off. I am hoping it it just low on Freon. The Owners Manual says that if the control button blinks when engine is first turned on there's a problem with the system. Well it blinks. Any tips on how to determine if its just low freon?

 

[Rabbit]

try the diagnostics outlined on this site.

Corvette C4 Diagnostic Codes

 

[clydeyb]

try the diagnostics outlined on this site.

Corvette C4 Diagnostic Codes

Thanks so much!!! Code indicates low freon!!!

 

[toptechx6]

Note that even after recharging with R12 you will need to disconnect the battery for one minute to reset the climate control computer or the compressor will not engage.

 

[Tobben]

Remember, the A/C isn't supposed to work below 4-5 degree celsius+. If it does, the A/C may freeze to ice. Or at least on modern cars (90-00+), and the c4 is modern .

 

[clydeyb]

Thanks for the tips. I did not know you had to disconnect the battery after recharging. I think I did read that you have to pull the radio fuse? and some other fuse maybe A/C, Ill have to re-investigate. But right now I'm trying to locate R12 freon and am have a problem. I still have a couple of places to check.

 

[doublefoxed]

Personally I would just convert to 134. This way you can go ahead and
put new seals orifice tube and receiver dryer in. But before you do charge
and that's a big if you can get your hands on some r12 I would find where
it leaked from.R12 is like gold... I have two 25# pots and I can tell you if you
find some it will cost you more than a retro fit would.

One more thing... Most gm products had 134a from factory 92 and above...
Though I haven't serviced many a/c systems on vettes... and it may be 94 for
them... insert my foot in mouth here...

 

[toptechx6]

Thanks for the tips. I did not know you had to disconnect the battery after recharging. I think I did read that you have to pull the radio fuse? and some other fuse maybe A/C, Ill have to re-investigate. But right now I'm trying to locate R12 freon and am have a problem. I still have a couple of places to check.

Disconnecting the battery accomplishes the same thing as pulling the fuses and saves you the trouble of locating the correct ones to pull.
R12 is available on E-bay if you can't find it locally, current price is about $25 per lb.and you will need EPA 609 certification to purchase it. The test (very easy) for certification can be done online, a Google search should find several who offer it.
While R12 is now quite expensive, conversion is not always the best solution, normally A/C performance is diminished by doing so. The system should be flushed of all existing oil and refilled with a 134A compatible replacement, it is advisable to replace the accumulator and all seals as well, if you do not replace the compressor and the seals are not compatible it may leak. Some suggest replacement of applicable pressure switches as well since 134A operating pressures differ from R12.


doublefoxed:
First year for 134A in Corvettes was 1994

 

[clydeyb]

Thanks all,
I was hoping it is just low on freon after 16 years. Isn't it possible that it just needs a small boost after all those years and not really a leak in the system?? What are your thoughts. Again I was hoping to just "top it off". Just wishful thinking on my part???

 

[doublefoxed]

While R12 is now quite expensive, conversion is not always the best solution, normally A/C performance is diminished by doing so. The system should be flushed of all existing oil and refilled with a 134A compatible replacement, it is advisable to replace the accumulator and all seals as well, if you do not replace the compressor and the seals are not compatible it may leak. Some suggest replacement of applicable pressure switches as well since 134A operating pressures differ from R12.


doublefoxed:
First year for 134A in Corvettes was 1994

Thanks on the year I wasn't sure...

I am ASE cert in a/c... when I was in the body shop not to many vettes
came in the Found on Road Dealership... otfl but As I mentioned changing
the seals and the dryer is what he would need to do.. Changing the high
pressure cutoff switch would be the only pressure I would change if any.
New seals for all lines come in all retro kits.. You can pop the line off the
back of the compressor and bingo.. change them and re tourqe.
But don't forget the orifice tube.

Now in my honest opinion if you can get some r12 and not break the bank
doing so and going to do this yourself then go for it with either way. Personally
I feel 134 is just like synthetic oil... it's great if all the gaskets and seals are good
but if not it will leak....

R12 to me is colder to boot.... I have a 93 astor van dual a/c and it still
has the factory r12 never serviced freeze you out of the van a/c i have
have ever felt.


one more side note... Have you put a good set of manifold gauges on the
a/c? Reason being a large amount of people go to autozone by these stupid
quick charge cans and over charge the heck out of a system. They think more
is better but it's NOT! When the air was on was the electric fans pulling air thru
the condesor?... if not you will have hot air out the vents and a shot compressor before long.

 

[toptechx6]

Thanks all,
I was hoping it is just low on freon after 16 years. Isn't it possible that it just needs a small boost after all those years and not really a leak in the system?? What are your thoughts. Again I was hoping to just "top it off". Just wishful thinking on my part???

Not at all, and I would agree with your theory even though it might not be approved by the EPA. :L All systems do lose freon over time, usually past the front compressor seal and especially if the car is not a daily driver.

 

[not4spd]

a/c should never leak as the system is sealed. If it's low on freon you have a leak somewhere. If anything I would at least do a leak check with some dye. The chemicals that make up r12 make for a colder a/c. That's why you will find people saying their old A/C systems always blew colder. However technology is amazing, I had a buddy that did a recharge on a Maxima that was R134 and was able to get the a/c to blow 32 degrees f. Freon should really only be handled by proffesionals. If you decide to do this task on your own I wish you the best of luck.

Btw r12 recharge in the dfw area costs around this
$39.99 to hook up
69.99 to 79.99 per pound of r12
And that's just for a recharge and does not include labor or parts when repairing. Not looking forward to having mine done.

R134 runs 19.99 per pound

Again good luck and let us know how it goes.