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Caddy blowing hot Pages: 12

infj23 on Sun March 08, 2009 5:35 PM User is offline

Year: 1997
Make: Cadillac
Model: Seville SLS
Engine Size: Northsta
Refrigerant Type: 134a
Ambient Temp: 87
Pressure Low: 122
Pressure High: impossib
Country of Origin: United States

Temperature in the middle outlet is 95. I tried several times but found it impossible to get my gauge fitting on the high side. The low side is obviously bad. Even without a high side reading (I'll try again but had to give up for now), any ideas as to what my problem is?

Thanks in advance to all!


bohica2xo on Sun March 08, 2009 7:01 PM User is offline

Is the compressor actually running? That low side looks like a static reading.

You need to find a way to get a high side reading.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

infj23 on Sun March 08, 2009 9:04 PM User is offline

More news:
Finally got my hose on the high side. Readings were about the same, both close to 120. So, I think you were right that it was a static reading.

On my car, should I be able to see the clutch rotating? If so, it is not. Last Fall, the A/C was intermittent, but revving the engine got it going. Now, nothing. My guess is bad clutch. Anything else I should check?

Thanks again!

GM Tech on Sun March 08, 2009 9:32 PM User is offline

Originally posted by: infj23
My guess is bad clutch. Anything else I should check?


Why not go with the odds? 65% of mobile a/c failures are due to a loss of refrigerant due to a leak...a bad clutch is less than 10% probability. Your H-6 compressor probably has a belly leak-- look for oil at the bottom of the compressor....

Do you have any messages on the dash about low refrigerant? Caddys can turn off the compressor when low on refrigerant and set the messages and codes...

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Sun March 08, 2009 at 9:33 PM by GM Tech

infj23 on Sun March 08, 2009 10:47 PM User is offline

Thanks GM Tech,
No messages on the dash. To check to see if a pressure switch was working, I disconnected the low side pressure switch. As soon as I did, I got the dash message about "very low refrigerant" and that the A/C was turned off. I reconnected the pressure switch, turned the car off, then back on, and the message went away. So I think it is safe to say that the car is not preventing the A/C from running.

If I recover and ensure that I install the right amount of 134a, would I need to add oil as well, or will the existing oil remain in the system? Also, how much 134a to install?

If it is the clutch, would you recommend replacing the clutch or the compressor and clutch in this 12-year old car?

Thanks again, again!

GM Tech on Mon March 09, 2009 9:03 AM User is offline

I'd check the underhood a/c relay next- see if it clicks as you put it in and out of the socket with the a/c requested- if so, swap it with the horn relay- if not, the a/c is being commeanded off by the PCM- This test will tell you which direction in the circuit to go- either upstream towards the PCM and its inputs, or downstream toward the compressor.....

I have also seen the wire to the clutch be tattered- take a good look at he diode in the wiring harness about 6-10 inches back from the compressor- see if by wiggling this wire if compressor energizes (this is only if relay is clickingi n above test) --

the chances of a bad clutch are pretty rare- unless it is a wide air gap- If you have voltage to the clutch, then ap the front of the compressor with a hammer handle- see if clutch engages- if so- wide air gap is problem- it can be adjusted with borrowed tools from Autozone...

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

NickD on Tue March 10, 2009 7:03 AM User is offline

Also seen an open ambient sensor making the computer think it's sub zero outside, dang warning light or service your AC only comes on if the low pressure switch drops below about 8 psi if the compressor is suppose to be running. Also have low and high side thermistors, in-car sensor, and a solar sensor that can mess things up. What I am not sure about if hitting the off and warmer buttons at the same time will get you into diagnostic mode to look at all these sensors, I think they moved all this stuff to a Tech II scanner, but worth a try. You definitely need a manual to work on these. Can download an manual.

infj23 on Sat March 14, 2009 9:42 PM User is offline

Hello GM Tech, Nick D, bohica2xo, and all,

Success? I checked the clutch relay--heard the click as I reinstalled it. Just to be sure, swapped it with the horn relay and the horn still worked.

Then, with the engine off, I hit the clutch with the end of a jack handle. I saw some movement, a whiff of dust, and the clutch appeared to move out from the compressor a hair's breadth.

I fired up the car, put A/C on full blast, and after a few seconds, the clutch started rotating. I watched for a few minutes and saw several cycles off/on.

Ambient was a cool 56. Vent temped dropped steadily and was still going down past 38 when I shut her down.

Success? Or will this clutch problem come back? What should I do now to make sure this is a real fix?

Thanks again!

Edited: Sun March 15, 2009 at 8:23 PM by infj23

mk378 on Mon March 16, 2009 2:08 PM User is offline

Use a clutch installer tool to pull the clutch plate on and close up the clutch gap some. I think the one you can borrow from Autozone will fit your later-model compressor as it should have metric threads. Have a clutch plate remover tool handy too in case you go too far.

infj23 on Tue March 17, 2009 8:01 AM User is offline

Thanks to all! I'll give the clutch gap adjustment a try.

infj23 on Tue March 17, 2009 8:06 AM User is offline

One more question: any chance I can do this clutch adjustment while the compressor is still installed, or will I need to remove it from the vehicle? Thanks again.

mk378 on Tue March 17, 2009 10:23 AM User is offline

Yes it is typically done while still installed, as long as there is clearance in front of the compressor. You may also be able to un-mount the compressor to get clearance, but not disconnect the refrigerant lines so the system can stay charged.

GM Tech on Tue March 17, 2009 11:01 AM User is offline

I do them while on vehicle- just pull splash panel up and out of way- turn steering wheel all the way to the right- jack car up- can be easily accessed.....without pulling any compressor bolts- on a Caddy that is the last thing you want to do- the rear bolts are a real PITA- especially the hose assembly bolt....

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

infj23 on Thu March 19, 2009 10:55 PM User is offline

Thanks to all! Really appreciate the help. I'll let you know how it goes. Hopefully get it done this weekend.

NickD on Fri March 20, 2009 9:09 AM User is offline

Rather inconvenient to pull a compressor just for a clutch, PAG oil is exposed to moisture, plus recovering the refrigerant and recharging. Seems like your problem is that you have too much clutch gap. I prefer to block up the left side and remove the wheel to get more working room. Since the tool can be setup either for installing or removing, has to be removed to change it. So set it up as an installer, and slowly close it up using a feeler gauge, and you don't want to go too far.

The idea is to set the clutch hub as close as possible, but not close enough to drag, I find 0.020" to be the most ideal so constantly moving the feeler gauge in and out while tightening until I start feeling drag. Of course you want to find your gap first before doing anything to make sure this is your problem.

Having driven Caddies for years, never like this new stuff where the compressor is mounted way below in road salt country, and to make matters worse, went to that interference fit clutch hub. When the compressors were mounted way up high, could do clutch work wearing a business suit, but didn't have to because the gap never changed.

infj23 on Sun March 22, 2009 6:06 PM User is offline

Thanks to all. Really appreciate the guidance. I was about to tackle the job so I went to AutoZone to borrow the tool. They had a lot of tools to choose from! So, I'm not sure I got the right one.

The tool I got reminds me a lot of a steering wheel puller. The main difference is that this tool has 2 "L" shaped pieces that grab the edge of what it is pulling rather than screwing in like a steering wheel puller. Other than that, same operation: tighten the bolt in the center to operate.

Did I get the right tool? Is this removing of the clutch by brute force right? My Alldata subscription doesn't give a very good picture, but what it does show doesn't look much like the tool I got. Autozone uses P/N 27001 for the tool I got.

Any more guidance for me?

Thanks again to all!

mk378 on Mon March 23, 2009 1:32 PM User is offline

That is not the tool you need. The one you have is used to remove the pulley from the compressor in the process of taking the clutch all apart, which you won't be doing.

The installer tool is two pieces that thread together like a bolt and a nut. The center part also has threads in the end that screw onto the compressor shaft. Then you hold that part still with a wrench and as you turn the other part, it presses on the clutch plate and forces it closer to the pulley. Chick has posted an excellent set of instructions with pictures in the past.

infj23 on Thu March 26, 2009 7:00 AM User is offline

Wonderful info! Thanks again. I found Chick's article you mentioned which is very nicely done.

So, just to clarify, for my job (reducing clutch air gap), I don't even need to remove the clutch. Just use the clutch tool to tighten it down some so the gap is .02.

Any benefit to removing the clutch, cleaning up behind it, and then putting it back on, or best to leave well enough alone and just close up the air gap?

Thanks again!

NickD on Thu March 26, 2009 10:00 AM User is offline

Removing just the hub may not prove anything, and not exactly easy to get back on, one danger is jamming the key into the seal to cause more damage. I prefer to hold the hub on with the keyways aligned, with a couple of light taps to hold it in place, then insert the key so the installer is pushing it in from the outside.

One reason to remove the hub is to also remove the idler pulley that comes after removing the belt, contains a limited lubricated double roll ball bearing where the grease gets hard as a rock, not easy to remove that bearing as it is crimped in, so I just carefully remove the seal, blow out the interior with choke and carb cleaner, heck, use a whole fresh can, cheap compared to the bearing, and pack it full with a high grade disk brake type grease and put the seal carefully back on after checking the races and balls for any pits. But should be good if you catch it in time. These bearings can seize within minutes with no warnings, and with a single drive belt system, break the belt and leave you stranded someplace. But by just removing the belt, if the pulley feels stiff while turning it, you already know that grease is hard, can leave it, if it spins real nice and easily.

mk378 on Thu March 26, 2009 12:58 PM User is offline

Just close up the gap some. The clutch is metal on metal contact so there is nothing to clean unless it gets a bunch of oil on it. It would be good to remove the belt and spin the pulley by hand to judge bearing condition. Also you want to spin by hand after adjusting the clutch to be sure you didn't go too far and cause it to drag.

infj23 on Thu March 26, 2009 11:26 PM User is offline

Nick D:

A quick question just to be sure. Are you talking about the bearing in the idler pulley or the bearing in the compressor pulley, or both?

Thanks again!

NickD on Fri March 27, 2009 9:36 AM User is offline

Around 80K miles or so, they all seem to go about the same time, alternator, idler, tensioner, and AC compressor idler and they all see the load of the AC compressor, PS pump normally lasts, it's lubricated but pay to flush it out and put clean fluid in it, water pump is also questionable with that many miles and additional load. And working on a sideways FWD V-8 engine isn't exactly easy, but a lot of bucks on the front of that engine. CS-144 alternator is miserable, uses a one way collet to hold the pulley next to impossible to remove, but you will also find the slip ring brushes worn down to nothing, and if they do, the brush springs wear a deep groove into the slip rings adding to the expense.

Blower motor is also about ready to go, not to bad, but will take out the blower control module that runs about 250 bucks if the bearings seize mostly due to corrosion on a CRS shaft that loves to rust like crazy, that 30 ampere fuse is worthless.

infj23 on Fri March 27, 2009 8:40 PM User is offline

Hello all, again,

I hit a snag. I jacked up the car, removed the right front tire, removed the splash panels, and there it was! So easy to access, I thought to myself--wow, this will be easy!

Not so. The tools I borrowed from AutoZone do not fit. Best I can tell, on the clutch installer, the center hole on the tool is 8MM metric. It is too small to thread onto the spindle in the middle of my compressor. I'm guessing mine is a slightly older model with standard threads instead of metric.

Same issue on the clutch remover, which I got just in case. It also would not fit in the threaded hole on the compressor.

AutoZone doesn't have a different sized tool. Any workarounds for this? Anybody know where I can find the right tool? Or am I missing something here?

Thanks again,

Chick on Fri March 27, 2009 9:47 PM User is offlineView users profile

the Northstar engine has the water pump on the rear left side of the motor.. I would hate to change one on the front in those cars, you would have to drop the whole carriage down..

the tool is pretty standard. The sponsor of this site has them, send an e-mail to and ask for the clutch installer removal tools, it pays to have them..

Email: Chick


Freedoms just another word for nothing left to lose

TRB on Fri March 27, 2009 10:09 PM User is offlineView users profile

This is what I would suggest for GM hub issues. Will have to double check if there is an 8mm R & R tool in this kit.


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Edited: Fri March 27, 2009 at 10:10 PM by TRB

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