I know nothing about air-con, so looking for some advice/suggestions please, apart from remove it!

Car has been standing for a few months and when I eventually started it, I found the A/C only blowing either hot or ambient (no cold).

Checked the FSM and confused myself more, but I did follow the book and check for any DTC’s on the A/C control unit…. no errors showing. I did notice that there is some hard sticky residue that has been flung onto the hood support rod, this is inline with the A/C compressor. I’m wondering if the compressor has had a front seal leak at sometime?, but then surely I would get a DTC for low gas!

The compressor clutch appears to be capable of ‘pulling in’, because if I switch the A/C on the clutch engages for a few seconds and drives the compressor, but then disengages again and that’s the end of any more engagement.

Any ideas where I should start looking?

Oh as a side note, I read that these units can be converted from R12 fluid to something newer. Is this easy/cheap/worthwhile and is there anyway to tell if mine has been converted by a previous owner?

Thanks

first off, if you have R12 available in your area, use it.

It is the better coolant. The only problem is that it messes up the ozone layer when it leaks out.

I suspect you are out of coolant, really. I am surprised the system didn't tell you that.

Also, the mixing door could be screwed up. That is what brings cold in, however, if its closed, you will get heat, regardless.

So... what year?

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If the mixing door is stuck, wouldn't the clutch on the compressor still engage?. Where will I find the mixing door, this is starting to sound like dash/interior strip down

Sorry forgot to mention, it's a 93 LT1 with the auto A/C system.

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It's doubtful on the mix door if the compressor only spins for a few seconds.

Try disconnecting the battery for a few minutes to reset the A/C programmer.

I'd think that if the freon was low, the compressor would not engage at all and you would get a code 09.

Thers's a good recent thread on cleaning the A/C controler buttons/contacts.

Converting from R12 to 134 requires some seal changes and possibily other stuff, IIRC.

If the the battery was disconnected and reconnected with the key on, the programmer logic could be lost.

Also do a code check on the dash (see out tech section for a how to).
Look for codes 66,67,68,69 in module 4.1. These are for the compressor and A/C compressor control relay.

Compressor kicks on, binary switch senses the pressures are out of range and cuts power to the compressor clutch = low on refrigerant. It doesn't take much refrigerant loss to do this and a small leak is likely. Equally likely is that a 'top off charge' will fix it right up.

Thanks guys,

I did read about the possible problems if the battery was connected with the key on. It wasn’t but before I replaced the battery I tried to start the car and all the dash/courtesy lights went out so perhaps this replicated a ‘key on’ situation. Will try disconnecting/reconnecting battery as suggested. Also check out the tech section… is this looking for codes on the DIC instead of the A/C controller?

95vette, out of curiosity, would a small leak not give me a low refrigerant warning or does that code only kick in with a major fluid loss?. Also wondering if there is any way to check the pressures… I see a shraeder valve on the evap canister!

If I take it to the shop for a top-up, will they know if there has been a mod on the system and which type of fluid is currently in it and what type of fluid to use?

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I would expect a low ref warning, but everything else points to low ref. You can check pressures with a set of AC gauges. There are 2 'schrader valves', one hi side and one low side. Yes, the fittings are different between R12 and R134 so the shop would have no problem knowing what to use.

Codes on the DIC will look at the pressure sensor,clutch relay and clutch circuit.
You need to know how to do this anyway for all the other stuff, engine faults,etc.

Andy (95) has a point on it taking a couple seconds for the pressure sensor to react.

The only way to ckeck the pressure at the Shraeder is with a gauge set. It's probably better to take it to a shop and they should be able to tell if it's R12.

Thanks very much guys. I'll try the easy checks and if that doesn't point to anything it's off to the shop.

Much appreciated the help.

top off that freon like 95 sez..purty commin prolem,,ifn she stops werkin real fast then she ll need help ,,but might werk fer 1-2 -3 seasons like bog sez what ya have be 1st thang ta figure,,biggar connections will be 34 ...i hafta add a can once a spring fer my ol girl

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Yup will do pappy. I'll have to find a shop that won't baulk at a corvette, I suppose all a/c systems are much the same.

I'm a bit concerned that we might have banned R12 over here, so I might have to consider a conversion too

good luck bro..jus thunk of you this morn as drove my vet to werk...headlights werk slicker n snot on a bowlweevul..gonna hafta do that on my kids trans am,,

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Thanks pappy. Living in Spain, I need to find an a/c shop that speaks at least a bit of english, I still get lost with tech terms - I'll give you a shout if I get stuck with the lingo.... I absouletly love reading your messages

Hello,

Sounds to me like you already set the stage for a compressor leak. If you are able to get your hand on just one can of R-12 and a can of Dye Charge you can refill the system and resume checking for leaks. As already mentioned if your compressor has leaked out R-12 the pressure switch is sensing this and is shutting down the compressor. If the compressor is off, it doesn't matter what the position of the a/c doors are or how fast the engine is spinning because the R-12 is not circulating thought the system and is not removing heat/Cooling (what ever technical term you prefer) from the evaporator in your vehicle.

If available i would advice charging the system with just 1 can of R-12 and a nice shot of dye. Likely (since you mentioned the oil) your compressor will engage when the pressure increases,... the car will cool, and it will sling the dye all over your engine compartment in which case you will know the shaft seal on your compressor is bad and you will...

A. Need to purchase a new compressor
or
B. Replace the shaft seal

Your choice really.

If R-12 is no longer available (check EBAY) or you want to do a conversion... R134A is a good option and will cool just as good as R-12 if setup CORRECTLY... We can get into detail on that later. HOWEVER you must solve the leak issue... if I remember correctly molecules of R134A are smaller and will cause the system to leak out that much faster....

Hope some of this helps,

DG

Hi Dan and thanks for the info.,

If I’m understanding properly, there’s something I didn’t realize creeping in here, but I know nothing about a/c so perhaps I’m getting confused. Is it possible to buy cans of refrigerant (where available) and top-off the system yourself?. I was planning on it being a shop job.

The only dealing I’ve had with a/c is in the house where I get a guy to come around and top the system when required, never really taken much notice of what he does for his 100euros either.

What made me start to think leak, was this build up of crud on the hood support rod in line with the front of the compressor, it started slow and at first looked and felt almost like soft black rubber, so I initially thought the serpentine belt was shedding it, as this crud built up it eventually became hard and brittle where it was stuck on the hood support rod… is this how refrigerant acts?

I ‘think’ much of Europe, including Spain, signed up to the Kyoto treaty, so I’m likely to be stuffed for getting my hands on R12, so it could well be a case of repair plus conversion. Is there anywhere you know of that I can read up on the parts needed and the procedure?... I have the FSM and don’t mind wrenching it, but all the FSM ultimately seems to say is ‘a conversion is possible, by a dealer’

Thanks

You can check this out.

http://forums.corvetteforum.com/c4-te ... 2268864-r12-or-r134a.html

Well, I don't know about Spain, but in the U.S. you can still purchase R-12. It is illegal to produce R-12 but not to purchase it. In some states you need to be Certified to purchase (I am) however it is all over craigslist and ebay. I looked on Ebay.es, I don't read in Spanish so I am having a hard time finding a can but I do see recharge kits (don't know if its real R12 or junk).

In your situation you are probably going to end up at an A/C repair shop. BUT, if you can diagnose the problem, half the battle is won and you won't have to worry about a local shop pulling the wool over your eyes.

To recharge your system (top off) you will need...
A. A charging hose for R12
B. A can of R12

You can buy the charging hose on ebay.com and have it shipped to spain, but I highly doubt you can buy a can of R12 on ebay.com and have it shipped to Spain.

Here is what I suspect based on the information you gave me. The compressor front shaft seal is faulty... the Ester oil in the A/C system leaked through the seal along with some R12, caught the compressor clutch and that slung Oil all over your hood. Of course this is all speculation based on the info you gave me.

If you can top off the A/C system with a can of R12 and dye, in theory the system will engage... the vents will blow cold air and the compressor will push out some more R12, oil and dye. You will see the dye on the hood and will be able to diagnose it as a bad compressor. Then you will need to take it to a shop and have the compressor replaced and the system recharged.

Please do these tests before assuming its the compressor and taking it to a shop to have it replaced. It may very well be something else... I feel like its the compressor, but the only way to be sure is to Test it.

P.S. This is very unsafe but i do it. If you jump a lead to the a/c compressor and force it to engage while the engine is running technically with what is left it should blow cool air... but keep in mind this is unsafe because if the system has a blockage you are building pressure and could damage the system further, or hurt yourself. Also, oil probably has been leaking out in which case you could damage the compressor further (lack of lubrication). If you are going to try this do it for just a very short time.... 1-2 mins.

Good luck

DG

From your description of the crud under the hood I agree with DG, the compressor front seal is leaking. For the cost of R12 and oil you could have any AC shop put a leak detector (slang term is sniffer) on it and confirm it.

Thanks for the input Tommy, Dan and 95.

Tommy, I guess I'm in exactly the same position as the OP in that link, but it doesn't look as though he posted a solution... darn.

Dan, I found this ( http://cgi.ebay.co.uk/EZ-CHILL-DIY-AI ... ain_3&hash=item483a439ba7 ) on e-bay and it looks as though the guy is in the UK and will ship to Spain, but digging deeper into the FAQ/link ( http://www.id-usa.com/pdf/inst/RKR-7.pdf ) he sends you to, it seems I would still need to do a conversion of seals etc first (if I'm puuting the info from the FSM and his FAQ together correctly). So I'm still trying to find out what particular seals and other parts are needed.

I tried your suggestion and forced the compressor clutch to engage by putting 12v across it - the comprssor pipes and the vent air flow did get cooler, not as cold as normal because I got a bit panicky and didn't let it run for long.

I check with a couple of local garages and I've been told that R12 isn't used here anymore, unless I find a rouge who will do it illegally, so it looks as though the conversion of seals etc has got to be first on the list.

A bit more closer inspection and you and 95vette are right, I'm sure the compressor front seal is shot - there is more signs of grud/leakage across the inside of the hood, all in line with the front of the compressor.

I'm not too keen, or financially flushed, to want to buy a new/recon compressor, which seem to be around 400-500US plus shipping and import duties (which are a killer), so I'm looking to see if I can find parts to do the repair and conversion.... anyone ever done this and have any tips/suggestions and also a list of parts needed for the conversion - the net brings up a few hits on earlier models, but can't find anything for a 93.

Thanks again guys.

The main point I was trying to bring up was resetting the computer by disconnecting the battery at the negative terminal. Let it sit for a minute and reconnect it. Make sure your key is off. Then recheck the A/C control function. The most important next step is determining which gas is charging the system. R134A or R12. From there you can determine the next best course of action which in my opinion is to determine where the leak is by introduction of a dye. From that point you can either upgrade the system seals if needed or repair the compressor if conversion has already been accomplished. I'm sure that many cars in the UK and Spain are equipt with air conditioning today. A larger repair faciility should be able to determine your problem and your fix. If you decide you want to do it on your own. Leak and refridgerent deternmination are essential. A 134A coupler will not fit on a R12 valve and an R12 will not fit on a 134A. Most people reccommend this task be done by a professional because there may be gas in the system that has to be evacuated to do repairs on the lines or compressor. If there is no pressure in the system, everything could be disassembled easily but proper proceedures for purging the system and recharging should be followed. Most people don't have the needed equiptment lying around the house. Keep us posted Fluff.

link

http://www.freeze12.com/

From what I understand the R12 system has different size valves on the high and low side and they use a screw on type hose connection. The R134A uses the same size valves on both the high and low side and used a clamp on type connection at the valve. Once you know which one we'll go from there.

Thanks Tommy,

I think I didn’t explain properly – sorry.

From looking at pics on the web, I think I have already established that it is R12. It is as you say, a large screw fitting on the canister (t’ween engine and rad) and a smaller screw fitting on the low pressure (t’ween the chassis rail and power steering reservoir).

I’m also pretty confident that the compressor front seal is/has been leaking – all the indications and ‘fly-off’ splashes align directly with the front of the comp.

Looking at the link you posted, it seems that the conversion from R12 to 134 ‘could’ be just a case of changing the fittings, of course, as you say, once the system has been vacuumed/purged. Other info that I’ve read talks about seals needing swapping out, which I think Dan suggested. Another site say’s the drier canister should be replaced if it is ever disconnected!…. So I’m getting a tad lost.

I don’t mind wrenching on it, in fact I enjoy it, just need to get all the ducks in a row before I start.

Hello,

Glad I could be of assistance... its very rare on here, most of these guys like Tommy, Andy, Kevin, and Jeff are always bailing me out of some sort of mess. I enjoy A/C work though.

Seems like your pretty much convinced you need the R134A conversion which is fine. You will enjoy the same cooling capacity as R12 and increase the value of your vehicle so its not all bad. I have just been pressing you to get the R12 into the system so we can FACTUALLY identify the compressor as the MAIN PROBLEM, however I think we all agree it is very likely the culprit. Oil and junk built up in between the clutch and the compressor would signify a problem with the main shaft front seal... Your testing of the compressor also indicates that the system is functioning correctly but not cooling to its full potential because of the lack of refrigerant in the system due to leaking front seal. I am 90% sure you have the problem pinned.

Now, keep in mind this may not be the only leak in the system. You may find yourself fighting other leaks IF you move to 134A. This is because the molecule size of 134A particles are much smaller than R-12 and have a tendency to leak out of areas where R12 would normally not be able to leak out of......

BUT HAVE NO FEAR!... a shop the PROPERLY converts your system to 134A will replace all the o-rings in the system which is the main leaking points of an a/c system. If your barrier hoses are in good shape, and your condenser (the radiator looking thing.... in front of the actual radiator) are not leaking, cracked, or damaged... 99% chance you will never face a problem during your ownership of the vehicle.

What you will need... or should be aware of if taking your vehicle to a shop to have the conversion done:

1. All the O-rings in between where the tubes of the A/C system meet will have to be replaced. This is mandatory... you will change them from black R-12's to Green 134A's.
2. You will need port adapters for the high and low side of the system so you can charge it.
3. The oil in the system (Compressor, Accumulator/Receiver/Dryer, and Condenser) will need to be changed from Ester Oil to PAG 150. This is also mandatory and will result in ill effects if not done correctly. AND you don't want to overfill or under fill the system with oil.
4. The Accumulator/Receiver/Dryer will need to be replaced. DON'T FALL FOR THE RUN AROUND ON THIS ONE PLEASE. This is that silver canister located next to your passenger side fender well. It is not expensive even though it looks expensive. They go for about $20-50 here in the U.S.
5. Finally if your system is a Orifice Tube type setup as most corvettes post 1968 are, you will need to move from a Fixed Orifice Tube to a Variable Orifice Valve. THIS IS WHERE THE MAGIC IS!!!!!!!!!!!!!!!!!!!!!!!!!!!!! MANY SHOPS WILL LEAVE THE FIX ORIFICE TUBE AND ALTHOUGH THE A/C WILL BE COOL IT WILL NOT BE COLD!!! THIS IS WHY R134A CONVERSIONS HAVE A BAD REPUTATION BECAUSE PEOPLE LEAVE THE R12 ORIFICE TUBE IN THE SYSTEM WHEN THEY CONVERT TO 134A AND THE SYSTEM NEVER COOLS THE SAME AS THE R12 DID.

And of course you will need to either replace the shaft seal on your current compressor or get a new one... but you already knew that.

I think I got it all... if I missed anything i am sure one of the pro's will chime in.

Good Day,

Dan

Hi Dan and many thanks, you’ve covered just about everything I needed to know.

One last question if I may, does anyone know where I can find a list of part numbers for the conversion and also where I can get the parts?

One thing that was constant in your message Dan was – it all needs to be done properly. If I take it to a local/generic type a/c garage over here I can guarantee that it won’t be done right. It’s a sad fact, but I’ve been around this block many times with the quality of work in Spain, so I’d much prefer to get the system purged/vacuumed at an a/c shop, do the conversion and the comp repair myself, then get it gassed up again and tested at the shop.

To give an example of the faith I have in local garages, my old Chrysler is being transported 600km to Madrid this week for a ‘proper’ repair on the transmission.

I just know if I give the vette to a local shop for the a/c that these special seals/orifice etc., won’t get done and they’d have it stripped down for weeks!

Thanks again Dan, guys.

Honestly, I really couldn't tell you if they are going to be able to do it properly in Spain. I am a typical American, I know about the U.S. and the rest of the world doesn't exist. Not really, but my point is that I know nothing about Spain and couldn't even tell you if you are going to be able to get the parts you need there.


Your best bet is call around and look for the parts you need. If that doesn't turn up anything then you need to hit the internet (which I am thinking is focused on Spain in Spain?) and take a look there. If all else fails

www.ackits.com is the "people in the know" site. You can get everything you need there and have it shipped to Spain from Arizona. This is where most of the technicians and car restoration specialists order A/C parts from. There parts are very good quality and CHEAP! Closely followed by Vintage Air which also has very good parts but is VERY EXPENSIVE.

As for the local shop doing the work, I would pick their brain a little first and see what they know about A/C systems. It doesn't necessarily matter that it is a Corvette as much as the fact that it has a standard A/C system. You are armed with some decent info, a list of parts for the conversion, and are now aware of the places to get them. This should be enough to help you find the right shop.

A/C systems sound complicated but when you break it down they are really not that critical. Its important they take there time and do a quality job so you can have years of A/C enjoyment. Nothing sucks more than having to go through this every summer. However, don't fear them "screwing it up" because really, the worst thing that can happen is they cause another compressor failure, as that the only moving part in the system. A/C systems rarely explode, and usually the worst consequence of making a mistake is that the system cools mediocre.

Good Luck,

Dan

Hi Dan,

No, I wasn’t asking if you knew about Spain, I do and I can tell you we have more cowboys over here than you do in the Americas when it comes to car repairs and service in general. You take a car into a shop in Spain and you can get it back with more spare parts than you started with (they tend to think… why put two bolts back when one will do the job!).

Yesterday I sent an e-mail off to a company called acsource.net (the best I could google), I’ll follow that today with another e-mail to ackits that you mention (they sound good), then I’ll try Vintage Air if need be.

Dan, everyone, thanks very much for all the help and info, really appreciated and I don't feel I'm going into this so blind now.

I’ll update how I get on with it in the future.

Well sent off those e-mails to Ackits and Acsource over a week ago... no replies . Do you guys find companies to be like this?... perhaps it's because I'm e-mailing from Spain! It makes me feel like not dealing with them, but one the other hand I don't have a lot of options.

Anyway a question - I've looked though parts lists and pictures on ACkits site and the drier/accumulators they list don't look like the original vette item. Is it normal to put a different type/patent offering on a vette?

I'm considering taking a flyer and ordering parts without the suppliers advice, but don't know if I'll be ordering the right things.

Any thoughts?

fluff brutha ive read this a tad bit n id think you simply lost a lil freon..when i have one blow warm etc i 1st look ferleaks (a lil by the compressor is ok ifn you ain warshed her off in awhilst,,but i aways shoot a can in n see how long it lasts,,my vet takes a can er two a season n my truck takes a can every other summar,,still way cheaper then buyin compressor er parts etc..key werds to me is in 1st post (clutch will pull in breifly) thats jus a tad low on freon bro...whats the rules on shippin to spain anybody ? is there a way we kin send this ol bro a can of r12 heyhuh...
yo fluff check this out (hope linkie werks) yea thats wud we all say as age sets in http://www.freeze12.com/ this may be n idear too

Pappy, many thanks for the thoughts and words.

I'm sure your right about it being low on refrigerant, I reckon your right about topping it off to get it working again.

Problem is, it looks like it has had a pretty serious leak and the residue is showing on the inside of the hood (I'll see if I can post a pic later)... so eventually I'm going to have to do a permanent fix.

Thanks again Pappy

Although I have never done it I would join their A/C forum and re-ask your questions on there. It may turn up the answers your looking for. The line is located at the top left corner of ACKits.com's homepage.

Chances are the pictures differ from the item you are going to receive, but I wouldn't chance it, I would still find out for sure before purchasing. However I have order many things from them and have never gotten the wrong item... but that's me.

It will probably cost you a few buck but I would get a calling card and give them a call... the number is on there homepage. Just remember they are in PST (I think).

DG