waddisme

System has dye in again and will probably be out by today. 1st run with dye showed nothing with lines, condensor, evap or anything you can see from top or bottom. Where should I look next - pull intake and look at lines behind there or is it probably somewhere under dash? It doesn't leak under vacuum, just when recharged. Charged it Friday and ice cold, but this morning, I could tell it wasn't as cold and it will be all gone by this evening.

Bill Curlee

Your best bet is to beg borrow or acquire a haylon detector. You can set the fan to low and sniff the center vent to see if you have a evap leak.

Sniff the joints for all the lines in the engine compartment. Make sure that you check BOTH fill ports. You can use soap water and apply it to the opening under the caps. If they bubble, its leaking.

Here is how the lines are set up behind the engine:



This is a view from the inside of the cabin from a cut away C5 chassis:

Quicksilver Vert 01

Check closely around the area where the compressor clutch attaches to shaft on the compressor. Leaks at the compressor shaft seal are quite common on GM/Delphi compressors.

waddisme

Thanks for the pix. Done the soapy water test with both fill points and at all seals. Car has been up on lift 2x thinking it would be the compressor but nothing. Will try to get haylon detector before I start tearing things apart. So far this year, I have already had to repl both front wheel bearings, removed the dash for HUD repl, had coilovers off 2x for adjustments, accusump is currently apart due to bad pressure switch(?), got high trans temp at track last week (fluid change I hope), and have only had 4 track days this year. I think my car is getting old.

waddisme

OK, I have checked everything to keep from pulling dash to keep. I removed condensor and no leak there. Pulled all the hoses and nothing. Nothing on hoses behind block, so wherever its going, it is inside the car. Searching for evaporator removal thread.

Bill Curlee

If the evap is leaking,,, you will have R134 in the Air Box. Give her a SNIFF TEST. If its leaking at the evaporator the sniffer will detect it. Pulling the EVAP coil out is a ROYAL BITCH!

I would check first. Have you tried the florescent Die and the black light??

Bill

Roc87

This is where mine was leaking. I would charge it and it was great for a day, then the next day only the passenger side was cold, never would leak enough to make the low pressure switch keep the compressor from working though

X2

waddisme

2 times with 2 different mechanics. Cannot find anything in the engine compartment. All that is left is the evaporator. AC did have a stange odor when it was working. So if it is leaking, is that repairable or just replaceable? Any benefit from flushing it? AC works like normal until freon leaks out so I don't think it would be blocked. Just looking for any possibility before I pull the dash again.

Quicksilver Vert 01

The chances of the evaporator leaking is FAR LESS likely than a leak in the condenser, since the operating pressure of the condenser is about 3-4 times higher than the evaporator pressure, and the condenser is in a more vulnerable location for damage.

Please don't pull the dash apart, for the evaporator, until you leak test it again with a reliable Halogen leak detector. A good detector can sniff out a leak that's as small as .25 oz. of refrigerant per year!

If the system is charged, you can check for an evaporator leak by sniffing the center dash air outlet with a Halogen leak detector. Check with the A/C OFF, and the blower fan on LOW. The evaporator will have the greatest pressure in it with the A/C compressor not running.

waddisme

Wherever the leak is, it is not in the engine bay side. Condenser is completely out, no sign of dye. Car is up on stands, so I get a good look at compressor, no sign of dye. Pulled all the lines, no sign of dye and o-rings are all in place. Pulled line that goes by header that is wrapped just in case it had developed a hole, but no sign of dye. I get a good look at the lines behind the block and no sign of dye. Whatever is leaking, is beneath the dash. Don't know where the seals are, but under vacuum, the system will not leak, but under pressure it does. Couldn't find any pics of the installed evap or a removal thread. Guess I will do one for future searches. Thanks for the input.

Quicksilver Vert 01

I have a 2001 shop manual set, and would be more than happy to find the evap R&R procedure if you need it.

Just send a PM if that would help.

RayCE

Similar problem with a C5 that is at my friends shop right now......It was leaking at the evap...........pain in the a$$ to repair.
good luck

curtbriggs

I have the same exact problem. I have all the tools plus the sniffer and can't find the leak. I was told that the symptoms sounded like a compressor front seal leak. I installed a new 4 seasons compressor and the problem still exists except now it won't hold vaccum either. I used compressed air to run the system up to 120 PSI and used soapy water, no bubbles anywhere. I originally thought it was the evaporator because the sniffer gave a low warning at the center vent. Was told at Gene's GM parts that they never have problems with the evaporator and the sniffer wasn't that reliable. I read the hint to test with the compressor not pumping, will do that next. I now have a lift in my shop and it makes it easier especially with the right front wheel off.

Had mice in my AC fan, wonder if they chewed on the evaporator.

Please let me know what you find and I'll do likewise.

PS, the 4Seasons compressor is made in Chinia. Their 37mm guns/ammo shot me down over Son La, NV in 65, I don't buy any Chineese crap if I know before hand.

Thanks to all, Curt

K-Spaz

This thread is 5 months old, so it's not likely any of the posters are watching it.

After a recharge, let the system sit for a few minutes without the car running. Then, while checking the vents, turn the car on and start the blower on low. If it's the evaporator, a decent tool should detect it.

Outside of that, putting dye in and looking with a light is as simple as it's going to get. Sorry to say but if you don't find it in the engine compartment, odds are it's the evaporator. Not a fun job as maintenance jobs go.

curtbriggs

K-Spaz, thanks for the come back. I'm not looking forward to that job either.

Curt

K-Spaz

Many of the leaks can be sneaky. I had mine sniffed and it must have been difficult to find all the issues because the first shop didn't find the evaporator leak. I had lines leaking, actually had one rubbed open. Leaking compressor (seals at mid body of the compressor were bad), and the evaporator. When I was done, the condenser and one line to it were all that was left of the original a/c.

If it comes to it, the evaporator is a huge job, make no mistake about that. But, in hindsight, if you stay focused on the work and just keep plugging, and follow the service manual very closely, you'll have no trouble with it. Set aside 8-12 hours. If I had to do another one, I'm pretty sure I could do it in 6 or 7. It's mostly clean work. And, if you're going in there, I'd replace the heater core at the same time. You'll be there anyway, that extra $50 ain't gonna change your lifestyle.

Btw, when I was done replacing my evaporator, all leaks ceased. however, you'd expect that I'd have seen dye on the old evap... nope... Not a sign that it was leaking, other than the sniffer saying so. I'm not sure how that's possible, but, maybe if the leak is up high, oil never gets there, thus dye doesn't come out. Idk. But mine had a confirmed leak with no dye showing.

curtbriggs

Good idea about replacing the heater core. I do have the shop manuals and thanks again for the comeback.

Cheers, Curt

waddisme

Saw this thread is back to life. Switching out the evaporator is on my winter project list. I plan on doing the pics with write up, but if you start before I do, maybe you can do the full blown diy writeup. I talked to someone who had just done theirs, they said it took about 15hrs, but they could do it a lot quicker again. Good luck with yours.

The Mountain Kat

I don't know about anyone else's experiences but if your A/C leak is a slow one like mine then it is too small and too slow for either the dye or the sealant to escape and work.
It seems that the sealants, (Moisture activated epoxy dust), and the dyes cannot work without a fairly fast leak.

curtbriggs

Before I replaced the compressor it would hold max vaccum, but would lose a 134 charge within 2 days. With the new compressor installed, the system will not achieve max vaccum, goes to about -20psi. To not waste 134, I charge it with 120psi of air so I can do a soap bubble test and it will go to zero in a matter of hours.
I'm going to remove the intake manifold and check the fire wall lines going to the evaporator and then, I'll charge it with 134 and use the sniffer again for the evaporator. I don't want to put the water pump or supercharge back on until I know for sure that the new compressor is OK.

Thanks, Curt