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Does A/C tend to run a bit warmish on 97 SLS's?


yukondude1

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To 97 SLS or STS owners:

Interested to know if this model is incapable of producing cold A/C, or is it just my car? Have replaced compressor, blower, evaporator, heater core, and more. Air runs "moderately cool", but I never really feel comfortable as I do in my other cars that also run R134a. When outside temp is in the 90's, I don't even like to drive my SLS.

Thanks,

Frustrated low mileage SLS owner.

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To 97 SLS or STS owners:

Interested to know if this model is incapable of producing cold A/C, or is it just my car? Have replaced compressor, blower, evaporator, heater core, and more. Air runs "moderately cool", but I never really feel comfortable as I do in my other cars that also run R134a. When outside temp is in the 90's, I don't even like to drive my SLS.

Thanks,

Frustrated low mileage SLS owner.

Was the system ever open to outside air for any length of time? You don't mention whether or not you replaced the accumulator/dryer, if the system is open, I understand that it destroys the active ingredient in the dryer and the cooling system does not perform well. I assume that you had it professionally evacuated and charged. Why don't you like driving your Seville? Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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To 97 SLS or STS owners:

Interested to know if this model is incapable of producing cold A/C, or is it just my car? Have replaced compressor, blower, evaporator, heater core, and more. Air runs "moderately cool", but I never really feel comfortable as I do in my other cars that also run R134a. When outside temp is in the 90's, I don't even like to drive my SLS.

Thanks,

Frustrated low mileage SLS owner.

My '96 SLS (same as your '97) will freeze me out of the car so yes, they are capable of producing cold air...

It appears that all those components were replaced without any diagnosis/troubleshooting. Prior to charging, was the system vacuumed down with a vacuum pump for a minimum of 1 hour? Was the correct amount of R-134a installed (2.0 lbs)? Was the system leak tested? Were the high and low pressures checked? Was the proper operation of the air mixer door verified?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Mike,

I don't like driving my Seville in hot weather because I can't get the A/C cool enough.

Your comment about the accumulator/dryer and the system being open for a period of time caught my interest. That is possible. I bought the car at 33,000 miles, and the A/c was inoperable at that time. The car had been in a wreck prior to my ownership. I took it to a Cadillac dealership and they had the car for 7 weeks!!

They pulled the engine, replaced the whole air-handling shroud (or box) low on the firewall, and replaced all the components I mentioned in my first note. Even after all that (it was a horrible experience dealing with this particular dealership), the AC still isn't cold. All kinds of analysis has been done on it. Except for this AC issue, I love the car.

Dean

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Hmm, this is interesting, do you have the receipt from the work. With that much damage its possible that air was in the system and the accumulator/dryer should have have been replaced but that is something that the Caddy dealer should have known. Check the receipt... Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Mike,

Checked receipt and no indication of actually installing a new evaporator. A note indicates an new "orfice fuse" was replaced. I've also been suspicious that part of the problem could be from vent doors (although they seem to do their job of diverting air to different vents).

Thanks for your ideas,

Dean

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Mike,

Checked receipt and no indication of actually installing a new evaporator. A note indicates an new "orfice fuse" was replaced. I've also been suspicious that part of the problem could be from vent doors (although they seem to do their job of diverting air to different vents).

Thanks for your ideas,

Dean

I would see what others here have to say about your situation. Kevin? Kevin is pretty versed in AC, lets see what he has to say. I think you may need the accumulator replaced, if the system is open to the atmosphere any length of time it should be replaced, otherwise I am told that cooling will not be so good.

I found this:

Desiccant and Driers/Accumulators:

The Receiver Dryer/Accumulator will serve the same purpose in both systems, however the CFC-12 system uses a desiccant named XH-5 and is NOT compatibly with HFC134a. The HFC will actually eat the desiccant bag, releasing the desiccant pellets through the AC system, damaging other components. In the HFC134a system, you must use a XH7 or XH9 type desiccant, which is compatible with both CFC and HFC based refrigerants. As a side note, I believe all driers/accumulators being sold now are crossways compatible.

NOTE: As a good practice, the drier/accumulator should be replaced after any service to the A/C system required it to be open to the atmosphere for any length of time

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Have you had the system leak checked? If it is low on freon, the system will not cool very well. On the other hand, if it is overcharged, the system will also not function properly. Do you know who did the work? A lousy A/C system would drive my crazy. I love to be cold. What about the compressor. Was it an aftermarket compressor? Does the compressor cycle alot or does it stay on. In summer heat, the compressor shouldn't cycle very often. If it does, it is an indication of being low on freon or possibly a restriction in the system. I've also heard of wrong orifice tubes being installed or not installed properly. Hopefully the fact that they couldn't spell it doesn't mean they didn't know how to change it. If the compressor is not cycling, feel the top of the drier and see if it is cold. If it is, I would then check the air mix door inside the vehicle.

Max

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They pulled the engine, replaced the whole air-handling shroud (or box) low on the firewall, and replaced all the components I mentioned in my first note. Even after all that (it was a horrible experience dealing with this particular dealership), the AC still isn't cold. All kinds of analysis has been done on it. Except for this AC issue, I love the car.

Are the vent discharge temperatures the same on the right and left sides?

It's possible an air mix door or linkage was damaged from the collision. If the range of movement is restricted or its ability to divert air around the heater core is compromised, air leaving the evaporator will be heated somewhat before reaching the vents. Blocking coolant flow through the heater core would be one way to test for this possibility.

Also, check for Diagnostic Trouble Codes (ACP codes in particular). The Climate Control Programmer (ACP) monitors the position of the air mix door actuators (left and right), and will set a DTC if they don't respond to commanded movements.

___________________________________________________

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For what its worth i will throw in my 2 cents , your A/C PROGRAM HEAD MAY BE OUT OF ADJUSTMENT, if it is you can turn it down to MAX COOL, and the controller may be out of whack enough , and think you want a 75 degree car, and that is what it will cool too. AT one time the dealer was the only one who had the equipment to plug into the controller to check it out. I do not believe the onboard diagnostics would tell you anything , if the controller was miss calibrated.

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Collision damage.....I knew there was more to this story...If the body shop left the system open for 7 weeks in a humid enviornment, I'd probably replace the accumulator. If they sealed off the system while the work was being done, the accumulator is probably ok. I would also check to make sure the orifice tube was installed properly. The short end goes toward the evap. and the long end toward the condenser. If the orifice tube is installed backward, it will damage one of the pressure sensors.

Have you checked to see if there any codes stored in diagnostics?

Have a shop hook up a gage manifold to the high and low pressure ports and obtain the high and low pressure readings. There is a performance chart in the shop manual that indicates the vent temperatures according to the outside temp and relative humidity. That will tell you a lot as will the pressure readings. The same chart has the high and low pressure readings. If the pressures & vent temps do not agree with the chart, then the system should be leak tested.

The shop could also recover the refrigerant from the car, weigh the amount recovered, add enough R-134a to bring the weight to 2.0 lbs and recharge the car.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thanks to all of you for your ideas and recommendations.

I don't know if the Cadillac dealership that had the car for 7 weeks left the AC system open. One of you suggested closing off the heater core to test whether vent doors may be allowing heated air to enter the system. I've looked at the 2 hoses coming out of the firewall (don't look easy to get to). How would you recommend closing off the flow to the heater core?

After reading everyone's comments it sounds like there may be a consensus that vent doors and or defective evaporator may be causing the problem. I will follow up on your ideas---thanks,

Dean

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I would not jump to the conclusion that the evaporator or blend door actuators are defective without further diagnosis unless you like replacing good parts..... :) I believe you can access the commanded blender door position and the actual door position data through the onboard diagnostics.

Get an A/C shop to hook up a gage manifold and obtain the high and low readings and post back.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Tried a bit of diagnosis this afternoon. Put my hand on the thing that looks like a tin can with a fat hose coming out of it. It was very cold to the touch, as was the large hose (AC hose). It was 92 degrees this afternoon. Noticed that the compressor seemed to turn off and on again somewhat frequently.

I removed the glove box and the panel underneath the glove box. Noted that all tubes were connected to the vacuum manifold. I turned the temp from 60 to 90 and observed that the door actuaters seem to operate well (Two were visible). I noted that the box surrounding what must be the heater core was very hot to the touch, which seemed normal. When turning temp from 90 to 60 the actuators operated and the vent doors seemed to do their job. However the air blowing from the vents is still only mildly cool, not cold. Impossible to be comfortable in the car in 90 degree plus weather.

I recently had the AC checked and freon added by "professionals". If it's not the vent doors causing the problem, and the compressor, blower, orifice tube, heater core, have been replaced, the evaporator would be the next possible defective component?

Thanks,

Dean

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Simultaneously press and hold the OFF and PASSENGER WARMER buttons on the climate control. Write down any codes that appear on the driver information center and post back the results.

You need to obtain the high and low pressure readings along with the ambient temperature and relative humidity. This is the very first diagnostic step that should be performed. I would not conclude that the evaporator is defective from the data you have gathered. Evaporator replacement is a huge job - there are 24 steps in the service manual...

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Today checked onboard diagnostics. No codes displayed. Under ACP I had hoped to find some way to do some adjusting, but there seemed to be no way to trigger any adjustment options.

At this point I guess I'm resigned to taking the car back to an AC place. I'm very gun-shy after the horrible experience with the local Cadillac dealer here in Spokane (incredible incompetence).

Regards,

Dean

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IF you have access too a vent temperature thermometer or can borrow one , what is your center vent reading with ac on max cool , inside air on recirculate and running car for about 10 to 15 minutes. ALSO what is outside temp reading when you take inside air vent reading.

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Reply to Franey:

I used a vent thermometer today. After running the AC on full blast (60 degrees & highest fan speed) with recirulate on, the middle vent temperature ranged from about 66 to 68 degrees. It's cooler today---outside air temp 66 degrees.

Any observations?

Thanks,

Dean

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Tried a bit of diagnosis this afternoon. Put my hand on the thing that looks like a tin can with a fat hose coming out of it. It was very cold to the touch, as was the large hose (AC hose). It was 92 degrees this afternoon. Noticed that the compressor seemed to turn off and on again somewhat frequently.

I removed the glove box and the panel underneath the glove box. Noted that all tubes were connected to the vacuum manifold. I turned the temp from 60 to 90 and observed that the door actuaters seem to operate well (Two were visible). I noted that the box surrounding what must be the heater core was very hot to the touch, which seemed normal. When turning temp from 90 to 60 the actuators operated and the vent doors seemed to do their job. However the air blowing from the vents is still only mildly cool, not cold. Impossible to be comfortable in the car in 90 degree plus weather.

Observing the movement of the actuators and mix door linkages does not confirm that the airflow path is correct.

At 92 F ambient temperature, the compressor should not cycle at idle if the HVAC blower is running at an appreciable speed. Your cycling observation suggests there's relatively little load on the evaporator; assuming the rest of the refrigerant system is operating normally, the incoming air could be bypassing the evaporator altogether, or the evaporator might have a manufacturing defect (short-circuited refrigerant path, in which case it never worked well). An ice-cold accumulator surface and suction line suggest the refrigerant charge is adequate for that particular load.

Is the evaporator inlet as cold as the outlet? Is the high pressure line leading up to the evaporator inlet hot to the touch?

___________________________________________________

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Finally got a chance to do some further analysis. Still blowing mostly warmish air.

With engine running and AC on 60 degrees, the accumulator/dryer is very cold to the touch. Also, the large diameter tube going into and out of the accumulator is very cold. The large diameter tube (low pressure I believe) going from the accumulator to the evaporator is very cold, as is the outlet to the evaporator, but only for a few inches (this is a small diameter tube). 6 or so inches from the evaporator on the small diameter line there is a fitting (or coupling), and after this point the line is no longer cold---warms up quite a bit.

Fan and vents seem to be operating fine, but I can't tell if heat from heater core is completely closed off when in cooling mode. I do observe that when compressor is engaged, colder air comes out of the vents, but compressor doesn't stay on long enough to cool the cabin.

Do these observations point to any issues?

Thanks,

Dean

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