ok it looks like i'll have to do the hot air from the ac. i know there are a million post about this and i know they will be very helpful. noticed it wasn't as cool as i thought it should be,just kept an eye on it for a while. had the dim light on the hvac and removed it and soldered the 8 resistors. everything went very good and it all works good. temp,fans mode,and auto seem to work good. started to get very warm but pass side was not as warm but still kinda warm. waiting on a couple adapters to show up for my ac manifold gauges then i'll start. meanwhile i checked a couple things. the compressor would not start until i jumped it.it would then run and the fans would run. had it serviced about a year and half ago. i always thought it should be cooler but the wife said it was good and that meant it was outstanding to me. i always thought ac work was black magic but it's time i learned something new. this is a 50k original mi and it looks like everything is oem. some of the post said to start with the DIC and look for codes. i'll do that first. tried the pull fuse trick but that did not work.when the adapters show up i'll get on the forum and start from scratch. also will have the vacuum tool. i just hope i don't have to remove the dash. i've done all my work on my hot rods in the garage for the last 55 years so i hope i have a few repairs left in me. all advice will be welcome. thanks Denny

 

From your description, it sounds like a loss of R134a charge. Was your system recharged when you had it serviced?

 

thanks for the reply. i think it was but then again i was not paying attention. it was 250.00 so it should have been.i know the mechanics and they are very good. when i learn how to use the gauges i'll check everything. when i took it in it was not very cool and when i left it was pretty cool.

 

Why does your gage set need adapters? Is it so old it’s set up for R12, or have the couplers just gone bad?
While the best option is a professional evaluation, a fairly easy and inexpensive driveway check can be done with a $40 recharge kit from WallyWorld or Autozone or similar — as long as it has a gage with pressure readings in PSI. With the engine off and the A/C system static the low pressure side should match ambient temperature. 90 degree day? 90 PSI. Again, with engine OFF, hook up to the low side — which is the only fitting a recharge kit will fit — and check static pressure. Bring it up to match ambient temperature, then start the engine and try the A/C. Don’t be surprised if it blows cold air, and, since all of the above would mean you have a leak, don’t be surprised if the fix doesn’t last until the leak is found and fixed.
Most common leaks I’ve read of on this forum are compressor case seals (ugh).

 

just bought it last week. it's new. hoses would not connect to ports on the car, had to get quick connectors for it. manifold did not come them. they should be here tuesday. ajso had to get a mto432 santech adaptor as i will be using the 16oz cans. can tap adaptor has 1/2 acme rh threads and the yellow hose would not screw onto it. santech adaptor will make it work. i'll start this project like you said and go from there. i have an advantage of a couple of good friends that are ac pros.and if things look strange i'll try to get some help. there also is some great help here. thanks for the reply

 

forgot to add that the compressor was not running when i looked at it saturday. friend showed me how to jump it. it ran and sounded ok. he mentioned i might have to jump it to add freon if needed.

 

If your system has lost all its charge, you should not force the compressor to run in order to pull in charge. Forcing charge into an empty system will contaminate the charge with air. Way back in the early days of R134a and the use of the first refirgerant recovery systems (the early 1990's), service techs were sometimes trapping air in the systems. This led to very high discharge pressures and failed compressors.

 

That your gage set is new but did not come with the appropriate couplers bothers me greatly. To my knowledge, all R134 cars have the same ports, one each low pressure and high pressure. This post from the past has much knowledge to share:
https://www.corvetteforum.com/forums...-ac-101-a.html

 

Take it a an A/C man. All shops with A/C gauges are not the same as a tech who does A/C work. 8/10 times...its not the compressor...or something super complicated. Its mostly low R134. These systems are designed to shutdown...and stay shutdown until levels and/or components are functioning properly. Much less compressor siezing and failures today in modern cars then once was in the past. I'm willing to bet a dollar that when you take it to the A/C...he tells you...yeah, it's low...we need to charge it. Then the compressor roars back to life and you roll away cool

 

thanks for the reply. we jumped it to see if it would turn on and that was all. have not put the gauges on yet so don't know where we stand. got a couple small projects going on now but should get to it this weekend. thanks again for the tip.

 

thanks for the reply. i hope you are right. that would be great if thats all it needed. we'll see this weekend

 

i have that post on my favorites. thats the one i'll go by. the hose ends will not hook up to the hi and low ports on the car.thats why i had to get the quick change adapters. at a quick glance the hose end is female thread and the port on the c5 is not a male thread but looks like a quick connection.

 

That’s what is so troubling. All cars, all of them, are quick disconnects. And all automotive gage sets come with the appropriate fittings. Are you using a home A/C gage set, set up for r410, r22, etc.?

 

no. the adapter male end goes into the hose and the other end is the quick. i noticed on e-bay that some of the other manifold sets come with the quick connect and are a few bucks more. had i known this i would have spent the few bucks more and got the set with with the quick connect. was looking at them earlier. same thing on the freon can adapter. was reading about the new freon cans that have a valve on them that seal. been a long time since i messed with ac. this will be a learning process as was the transmissions,engines,suspension in the muscle era. i'm 76 and consider myself very to go through that time with the old school mechanics that taught me well.

 

ok redzg i got the skinny on the hose adapters. when i started this project my ac friends said to get the manifold gauges. so i did. if you look at all the manifold gauges on e-bay and amazon the entry level ones don't come with the quick ends and the more expensive ones do. my friends probably should have said to get the set with the quick ends. so you have to order them separate, which i did. googled replacement auto ac hoses and the cheaper ones came with 1/4 female ends and the more costlier ones come with the quick with them. got some advice on here to grab a can of freon with the gauge attached to it and go at it. i have had success with that method and some not. asked my ac guy about that method and he ask me what the high side showed. he got me on that one and thats when i decided to do this project. that post you showed is a good one and thats where i'll start. it's on my favorites. thanks again for the response.

 

small up date. had a few minutes friday and my ac tools showed up so i hooked them up to get an initial check on whats going on. temp 86f humidity 64. nothing turned on and a static measurement. low and high barely 15. car running with ac turned up and fan on high and rpm 2000, nothing as in zero.on the way into town i stopped by the shop where my friends worked on it a couple years ago. they are up to their ears in ac work here now. Don said my next step should be to get an UV light and find the leak. when they do ac work as standard they use diy. had a truck in the shop they were doing and he showed me the leak in it with his light. one step at a time and next when i find the leak try to fix it. then evac. and vacuum. have some domestic stuff to do now so could be a while when i get back. all advice welcome.

 

Been there, done that. Thing or two to ponder: since you'll probably be adding refrigerant with dye to look for leak sources, adding enough to bring the static pressure up to match ambient temperature will allow the system to turn on and function -- assuming components are O.K., other than the low pressure. Vacuum is the tool to ensure water boils off and the system is dry, but pressure is better for determining whether there is a leak or not. All the seals more-or-less work both ways, but the primary seal purpose is keeping refrigerant in. Be sure to check the Schrader valve cores quite early in your leak path investigation. Total pain to go through evacuation and charging only to find out that all the good numbers go to heck when you disconnect the gage lines. And as a final note, my gage set disconnects have thumb screws to engage the Schrader valves. I pull back the outer ring on the disconnect to engage the fitting, then tighten the thumb screw to open the Schrader and observe pressure (or vacuum). If I tighten the thumb screw any further than necessary it can (and has...) bend the tip of the Shrader core, creating an all new leak.
On my '99 with a dead system, I used a can-with-gage to bring static pressure up to 90 PSI on a 90 degree day. Started the engine, hit the switch, and very quickly had wonderful cool air coming out of the vents. Lasted almost an hour before the leaking compressor had consumed all the R-134.

 

hey redzg. got a uv flashlight from the harbor and crawled under to see what i could see. lots of green from back of compressor at the tube manifold. also some on the low schrader valve. found my receipt from the last time it was serviced and was just two years ago to the month. was 180.00 not the 250.00 i thought it was. got a couple cans of r134 and i'll have to do the vacuum. nothing in the system now. i punched the schrader valves real quick and nothing. i now remember when i looked under the car for my weekly inspection early this year i remember that the compressor looked pretty gunked up. was going to check it again but forgot. receipt also showed new schrader valve on the low side.my guy says to use some dye when i recharge. not too sure about the pag oil,i forgot to ask about that. what do you think?. your advice is very well taken. your gauges seem better than mine. thanks, i'll keep going.

 

Perhaps you will be lucky and it is just the seal washers between the hose manifold and the rear of the compressor that are leaking. The large diameter body o-rings on my '99 are leaking a bit and one of these days, I will need to replace my compressor.

A small amount of oil seeping out with the refrigerant leak goes a long way towards making a visible mess. The system is charged with 8 ounces of oil. There are multiple factors that lead to GM/Delphi selecting that amount. The oil circulates with the refrigerant, an ounce or 2 is within the crankcase of the compressor, perhaps an ounce or 2 within the accumulator/dehydrator.. Within reason, the only downside to having too much oil is that it degrades the a/c performance. Since it circulates with the refrigerant, it basically takes the place of some of the R134a as it condenses to a liquid in the condenser and then expands through the orifice tube to flow through the evaporator. If you are nervous about the quantity of oil you may have lost from your leak, adding 1 ounce (to bring the total oil charge up to the factory 8 ounce plus the added 1 ounce minus the unknown loss that is gunking up your compressor and engine) will not make much of a difference in a/c performance.

 

thanks for the reply and info. yes i'm a little at a loss as to how much oil to add. although the system is empty i have not opened it up. i'm collecting all my supplies right now as i want to recharge the same day as vacuum. i have decided to replace the manifold line seals at the compressor,vacuum,add oil and freon and dye. i hate to be down in what i call the summer driving season. if all goes well i'll revisit this problem this winter season. got so hot this weekend i was afraid i would burn my hand on the t-handle shift ****. black interior gets hot. thanks again bookyoh