1999 Jeep Grand Cherokee A/C Problem

Compressor seal?

I'm not an a.c. expert, but I would think two weeks to leak down is not considered that slow a leak (i.e., should be detectable by normal means). Have them put refrigerant laced with UV dye so that the leaked residue can be spotted at the source of the leak. You can DIY, or take it to an a.c. shop.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

It takes practice to use a refrigerant sniffer properly to catch slow leaks. Before I finally started doing my own A/C the usual process I saw the corner mechanics doing is to park the car in the lot, idling with A/C running. That will only get the obvious ones. The way to catch the small ones is to park the car engine off inside a garage with the door closed, and clear everyone out except the person with the sniffer, and make sure there's absolutely no air movement. Then with the sensitivity at max, ever so slowly sweep the system, all hard and flex lines and all components, and make sure the probe is under the line, not above it, since refrigerant is heavier than air. The engine and ac system should be hot. And also sweep the evaporator inside the passenger compartment. This should only be done with slow leaks since refrigerant in an enclosed space can be dangerous - it displaces air and you can suffocate.

This process can easily take an hour or two to narrow it down, and might also require pressurizing the system with extra refrigerant (which should be removed before the compressor is started, of course) All in all not something most garages are willing to do unless you push them, since it's costly. And it's worthless unless the leak detector is really sensitive, which the cheapie ones are not.

I have never been a fan of the dye. Dye wicks along the outside of the pipe and is worthless to pinpoint exactly where the leak is, unless you look for the dye right after you put it in the system. And once you catch the leak you have to clean the dye off the outside in order to make sure there aren't 2 leaks really close to each other.

Dye never was that popular until they started putting out UV dye, because then the customers couldn't see what a mess it made of the pipes and such inside their engine compartment.

Your probably losing an ounce a day, which isn't a slow leak. A slow leak is something like an ounce a month.

Ted

what a crock !!!!!!!!!!!!!!! it's obvious you have really never used one i also did not trust one at first but i use it now as part of a 2 step checkout and i never miss a leak i turn on the ac and stick it the vent with ac full on. then i place it on the floor, and then shut off the engine and insert the tip into the drain it it leaks it will let you know the mac one we have is the best one i have used i used the dye to find the big leaks but it also hides leaks at the service valves were the sniffer doesn't oh ya in this hot weatheri don't even shut off my bench fan thats pointing at me

Ted Mittelstaedt wrote:

I own one, a Robinair. I know how it works and have had plenty of practice. And years before, back in the early 80's when the only electronic probes you ever used were in your sex toy drawer, and before the idiots in the auto industry figured it out, I was using electronic gas detectors very similar in construction to the modern ones to sniff out gas leaks in production of high voltage power equipment.

checkout and i never miss a leak i turn on the ac and

shut off the engine and insert the tip into the drain

I told him that you have to check the evap. But the evap isn't were most of the leaks are - or at least, not in most other cars that don't have evaps made out of paper mache like Chrysler's apparently are. I never heard of an evap leaking until I bought a Chrysler. It's asinine - the evap is the worst to remove part of the AC there is, anyone with half a brain would have designed it with extra thick piping and such. All the other automakers figured this one out.

Every part of the refrigerant circuit in an A/C is a potential leak. I've seen a leak in a 2 year old condensor right smack in the middle of a piece of tubing. Manufacturing defect that was - a quick bit of work with a welding torch and that condensor has lasted for 25 years now - and this wasn't no hairline crack, this was a true metal flaw about the size of a pinpoint. It took a jewelers loupe to see it and the leak was so small that the system took 2 years to leak down to nothing. Your not going to find that sort of thing by jamming your probe up the condensate drain.

service valves were the sniffer doesn't

Like I said, what your doing will only get the obvious ones. So your missing the small ones and your customers are too bonehead to understand that it isn't normal for an A/C system to have to be recharged every year, so they aren't coming back and jamming your probe up your ass for doing a half-assed job checking out their cars.

Ted

Oh yeah, I forgot that the foundrys that manufacture tubing figured out how to make absolutely perfect metal products with zero defects back in 1996, me bad...NOT!!!

R134a systems are just as suceptable to leaks as R12. There is nothing in Freon that isn't in R134a that hastens system deterioration. Vehicles subject the tubing and other parts of the refrigerant system to vibration, and over time that will shake free weaknesses. Joint seals can also fail. Flexible refrigerant lines have always been a problem - why do you think it is so rare to have a refrigerant leak in something like a home refrigerator that just sits there, as compared to an automobile? Or a home A/C system that uses copper braized fittings throughout except in a few places where there's large compression fittings? Geeze, they use the same refrigerant!

Sounds to me kind of like your working in a dealership. So, OK I can understand - your allotted only a few hours to make a repair and you aren't allowed to spend the time to really throughly check out the system. Slap it together quick and nail down the big leaks and let the seepers go out the door, the factory isn't paying you to really do a through job. Just don't be an idiot and assume that just because you don't have the time to do it right that what your doing is the proper way to do things.

Sure, statistically most NEW systems won't have slow leaks since those are more a factor of age deterioration rather than some gross failure. So you can get away with ignoring most of the system. But that only means that a smaller percentage of seepers will go out the door on your watch - they will still be going out the door, though, and if you checked all of the cars going out the way you should be, you would catch them.

Ted

just so *u* know, You're not impressing anyone with your exploits. [PREDICTION] See assenine knee-jerk reply below. [/PREDICTION]

Ain't that a wonderful law? Let's see, who is required by law not to let a leaking car out of his garage YOU ARE. Who is charged with determining whether a car is leaking or not YOU ARE. Do you see a problem here?

How about we rewrite the speed limit laws so that the person charged with following the speed limit - the driver - is also the person who types in the speed limit he was travelling into the cop's radar gun. I'd go for it!!

When are you going to understand a lot of these EPA regs have no teeth in them and are just to make the tree-huggers happy?

It's like the law mandating recovery of R134a. So, tell me, the refrigerant industry spends years and millions developing a refrigerant that is safe for the environment - then they pass a law saying that this safe refrigerant can't be released into the environment since it's unsafe?!?! Then they go ahead and let the industry sell it in 12 ounce cans over the counter at auto parts stores to shadetree mechanics who do not have the expensive recovery gear?

Do you see a problem here?

Ted