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'97 Seville SLS not pulling in refrigerant

gunbunny on Mon May 30, 2011 10:01 PM User is offline

Year: 1997
Make: Cadillac
Model: Seville SLS
Engine Size: V8
Refrigerant Type: R134a
Ambient Temp: 90°
Country of Origin: United States

My wife was complaining the other day that her a/c wasn't cooling effectively, and that her driver information center was flashing "LOW A/C PRESSURE. COMPRESSOR OFF".

So two days I grab my hose with gauge and a can of refrigerant. This is the first time I've worked on the A/C on this car, but I've done our others more than a few times before, so I figured "no big deal, I'll be done in half an hour."

I locate the low-side port and remove the cap, then connect the gauge to it. The needle barely budges, and I'm guessing it's about 5psi. I hook a can of R134 to it and pierce it (but don't release it), then I start the car and turn the A/C off and wait for it to warm up a little. It was about 80° out, so I didn't have to wait long. I then turn the needle to release the refrigerant and turn on the A/C. I hear the click of the compressor coming on, and it took some in, but not fast enough and the compressor shut off again. No big deal, I've been here before. I shut the car off, wait a minute and repeat the procedure. A few more times and the can is getting cold, and the compressor is staying on. I fill it till the needle hits 50psi, and disconnect everything. The A/C is blowing cooler but not cold, and there's still about half a can left, but I didn't want to over-pressure the system.

So she drove it today in 90° heat, and came home and said that it was blowing hot air... not even cool anymore. So I hook the gauge back up, and it's at about 10psi. So I turn on the A/C, open the valve on the can, and the needle all of a sudden jumps to 60psi. The can isn't getting cold and neither are the hoses. I wait a second and the needle jumps to 80psi. I close the valve on the can and disconnect the hose. Turn off the A/C and shut off the engine. Wait a few minutes and hook up the hose again, and it's showing 10-15psi. Start the car, hit the A/C, open the valve... and the needle buries in the red... 100psi+. I immediately disconnect it and the needle stays buried. Obviously a bum gauge, right?

So I dig around in my garage an unearth a couple cans of "Quick Cool" (the kind with the clear hose and built-in connector) that I got on an end-of-season clearance at Target. I had used them before on my old Saturn and they seemed to work without a problem. I hook it up, depress the button... I see the fluid fill the tube, some bubbles, and some of it blows back out through the button. A few more depresses of the button.... same behavior. I take the connector off, and go to re-seat it to make sure it's connecting correctly, and the damn thing won't connect at all now.

I try a different can, same thing: can't get it to connect. A little force and the connector on the hose with the now-broken gauge finally goes on. I pull it off, then try the "Quick Cool" again, same spray-all-over behavior. I take it off, go to re-seat it... and again, it won't go back on.

I'm wondering if the valve on the low-side pressure port is sticking or if there's something else I'm missing. Any and all advice welcome. I hope I was descriptive enough with the problem.

mk378 on Mon May 30, 2011 11:22 PM User is offline

There is a major leak. Pressures of 5 or 10 with the compressor off mean that practically all the refrigerant is gone. It's going to take much more than one can to restore operation, and then it is just going to leak out again.

Don't use the junky hoses with inline gauges. You need a manifold that shows both pressures. Also don't try any sort of "stop leak." None of them work to stop leaks, but they will clog up and ruin the whole system. Find the leak and replace the leaky part.

Edited: Mon May 30, 2011 at 11:27 PM by mk378

JJM on Wed June 01, 2011 12:14 AM User is offline

Is this meant to be a serious question?

If so, the way you're going about A/C repair is positively all wrong. You don't just go and grab a hose with a gauge and a can of refrigerant and start charging when you think there's a problem; a proper diagnosis needs to be made. The system is seriously low on refrigerant, probably a case leak on the HD6, with a significant corresponding oil loss. What do you think is going to happen if you keep adding refrigerant with no oil left in the system?

Do you even know what's in this "Quick Cool" stuff you're adding to the system? If there's sealer, you're looking at a total system replacement. The system is now beyond repair, since once the system is opened to repair the actual leak, the sealer will harden when exposed to the atmosphere, clogging up all the components.

As for fear of over-pressurizing the system, how would you know testing only the low side of the system. The low side can stay very low due to a restriction in the OT (likely if refrigerant with sealer is used) and the only way you'll find out the system is overcharged is when the shaft seal blows out or a hose bursts in your face.

In any event, it's your money, your vehicle, and your safety.


When considering your next auto A/C purchase, please consider the site that supports you:

NickD on Wed June 01, 2011 5:42 AM User is offline

What the immigration services and copyright laws of this country share in common, is its a 250,000 buck fine and a five year prison to marry an immigrant just to bring that person here or to copy a DVD.

In the case of immigration if fraud is found, the US citizen sponsor pays the fine and goes to jail, but if the immigrant can prove a hardship in going back to their home country, can stay here, but worse case is just being deported. In the case of copying a movie, okay to copy it off cable with sound surround and HDTV so you get high quality, but not okay to copy it off a DVD to watch later. But in the latter your quality will be far poorer.

EPA is a bit more lenient, same fine for bypassing a catalytic converter as is continuously topping off a leaking refrigerant, even with environmentally friendly R-134a, fine is only 25,000 bucks. But this brings up the question is why is the sale of these death kits legal?

I feel the logic is, the EPA wants to you wreck your vehicle so the repair cost will be more than what your vehicle is worth and that car will end up in he crusher so you buy a new vehicle with much tighter EPA regulations. Thus overall, the environment will be better.

Can walk into any mart store, pay cash, with no traceability to that purchase and play with it in the privacy of your garage. On the other hand, if a professional, purchase of refrigerants is traceable.

Looks like the EPA succeeded in getting yet another old vehicle off the road.

gunbunny on Wed June 01, 2011 9:04 PM User is offline

Yes, JJM, this is a serious question.

I'm your average "shade tree mechanic" that enjoys tinkering with his cars and fixing as much as he can on his own. And from AC recharges to replacing fuel injectors and radiators, I've done a little bit of everything.

For what it's worth, I've used the various "mart store" cans on a few different vehicles... successfully. But this is the first time I've had to charge the Caddy, and it's not behaving like the others. Which is why I'm here asking for help.

So here's my update, in case anyone feels like helping me out rather than taking me to task for not being a professional.

I chucked the hose with the in-line gauge that is now permanently stuck at the max peg, and bought a gauge only that connects to the low-side port. I also bought a pair of 12oz cans of R-134a (plain, no oil, no leak-stop. Identical to the original 12oz can that I had connected to the hose with in-line gauge that the Caddy only took half of, and is now sitting in my trash can still connected to the hose.) I came home and checked the pressure with the engine off: 100psi. So I bled it down to 60psi and turned the car on, turned on the AC to max cool, and its blowing hot.

So for all intents and purposes, the "Quick Cool" stuff with leak stop, referenced in the first post, never made it into the AC system... the system was already at 100psi, which is why the "Quick Cool" blew out the valve on the top of the can and wound up all over the engine cover. (Which is now all nice and shiny thanks to the oil in the stuff.) So the system went from 5psi (if the original bum gauge was to be believed) to 100psi on about 6oz of R134.

Any ideas what may be wrong and where I should start looking to fix this?

mk378 on Wed June 01, 2011 9:58 PM User is offline

Well you should be taken to task here since you are not using the proper tools, which is compounded by the apparent fact that you don't know much about what you are trying to do. Both of those conditions can be remedied though. It is necessary to at least own a proper gauge manifold that can measure both pressures at once in order to be considered even a novice A/C mechanic. They are not expensive compared to the parts you will destroy trying to do without.

A Cadillac typically has a complicated control system with at least one computer constantly measuring refrigerant pressures and temperatures, and it will "lock out" the compressor (and display message to the driver) if a problem such as lack of charge is detected.

Pressure of 100 with compressor stopped and 6 oz of R-134a is completely normal.

Edited: Wed June 01, 2011 at 10:01 PM by mk378

gunbunny on Thu June 02, 2011 9:16 AM User is offline

I know that the Caddy has a computer-controlled A/C system... As I stated in the original post, the Driver Information Center did display a message "LOW A/C PRESSURE. COMPRESSOR OFF" prior to me starting this. After the system took the half can, the error has stopped appearing.

So given that:

1) It's holding what you say is a normal charge


2) The compressor is coming on

care to hazard a guess why it's still blowing hot?

mk378 on Thu June 02, 2011 11:49 AM User is offline

I didn't say it was a normal charge. I said it was normal to see 100 psi with a 6 oz charge. If there is enough refrigerant to condense one drop of liquid in the system, the pressure with compressor off will be the same as with a full charge. One drop of liquid will not produce any cooling. The only way to absolutely know the charge amount is right is to start from empty (vacuum) and charge by weight.

JJM on Fri June 03, 2011 12:11 AM User is offline

A number of folks on these boards are not so-called "professionals", but they do have the requisite tools and knowledge to perform A/C system repairs as effectively as any professional. The methods you are describing to service a A/C system are not only incorrect and obviously not producing results (otherwise you wouldn't be having issues), but will cause damage to the vehicle and possibly even serious personal injury.

I can get the lights to work in my house with speaker wire, and hook up gas appliances using garden hose, but are either of these methods proper, much less safe? If I have hole in my exhaust, I'm sure I could wrap a Pepsi can around it and it'll work, as would some duct tape to hold up a window with a broken regulator, but that's not the way I would ride around.

The electronic systems on the Caddy have little do with why the system is not cooling. It's all just basic air conditioning (though the Caddy system is a bit trickier due to the location of the service ports) that can be easily diagnosed with the basic air conditioning tools. I can assure you the proper tools don't come from a clearance sale at Target.

But again, it's your money, your vehicle, and your safety. We can help with everything you need to know to get any system working properly, from a 1950s classic, to a brand new 2011 model that a dealer might be stumped on, but you need to get some basic tools first.


When considering your next auto A/C purchase, please consider the site that supports you:

dwhite5549 on Thu June 09, 2011 12:50 PM User is offline

Good morning Joe,

I have a question for you because you really seem to know your stuff.
I bought a peach of a 92 Cadillac Seville and the R12 A/C doesn't work.
I brought it in for a leak test and the tech told me that I needed to replace the condenser.
No problem, I'm going to replace it.
My problem comes in after I replace the condenser. That replacement is a fairly simple "mechanical" job.
After that I have no clue what tools I need and what steps I need to take in order to check and refill the oil in the compressor and recharge the system.
Would you be willing to help me out by listing the steps?
I know it sounds like a lot but you seem to care about people doing the job right and I would like to learn how to do it right in order to service my wife's and daughter's vehicle as well.

Thanks in advance,



JJM on Fri June 10, 2011 10:32 PM User is offline

You sure the condenser is leaking and not the evaporator? The reason I ask is a lot GM vehicles of that era had leaking evaporators.

Before you start throwing money at it, I would suggest an inexpensive UV dye leak test to confirm if it is indeed the condenser, or evaporator, or anything else:

Mastercool Professional UV leak Detection Kit

Best $61 you can spend.

Even without UV a condenser leak is pretty obvious since it's under so much pressure... black oily residue would be a telltale sign. Ditto on the evaporator, though it's often harder to see.

In any event, assuming it is the condenser leaking, it is a pretty straightforward job. Recover the refrigerant in the system (if there's anything left in there). Carefully undo the refrigerant lines, top radiator support, and remove the condenser from the vehicle.

Now that the system is open, you'll need to remove the OT, accumulator, and any lines with mufflers, and flush the system thoroughly. Given the car is nearly 20 years old, the accumulator must be replaced, and if you're sticking with R-12, I would definitely replace the hoses and compressor shaft seal - both inexpensive - you don't want to lose any of the valuable R-12. You'll also want to replace all the o-ring seals and OT (all inexpensive)

If sticking with R-12, 8 oz of 525 mineral oil would be added to system. Then vacuum the system down for a good 30 minutes or longer (if you have a micron gauge, try to get below 750). If vacuum holds, charge with 2.38 pounds for R-12. Your system will be like new (provided the compressor isn't damaged).


When considering your next auto A/C purchase, please consider the site that supports you:

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