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2003 Cadillac CTS !!Help!!

josecamacho on Tue April 09, 2013 6:18 PM User is offlineView users profile

Year: 2003
Make: Cadillac
Model: CTS
Engine Size: 3.2
Refrigerant Type: r134-a
Ambient Temp: 95 f
Pressure Low: 75psi
Pressure High: 125psi
Country of Origin: United States

I'm a mechanic in Phoenix and we have a problematic vehicle here that will not cool at all.

We replaced the A/C compressor, Condenser w/dessicant, Expansion valve and it came back soon after not cooling at all. The compressor clutch is engaging and we did flush out the system (except the evaporator) when the parts were installed. We've tried another TXV, 2 new compressors (the latest a genuine AC Delco boxed Denso unit), we replaced the condenser again and still no dice... Never seen anything like it.

Any sugguestions?

BTW the pressure differential at the condenser inlet (90 degrees) and outlet (95 degrees) is virtually non existent.

Any help is greatly appreciated.

TRB on Tue April 09, 2013 9:55 PM User is offlineView users profile

What brand compressor are you using? What's the charge level?

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NickD on Wed April 10, 2013 9:41 AM User is offline

At 95*F static pressure is around 100 psi, are you running the engine at 1,500 rpm to see the lo side dropping only 25 psi and the high side increasing to that same amount?

Assume you have charged by weight, even a wide open TXV couldn't cause a low pressure differential like you are seeing.

All I can suggest is that you take this car to Tim.

josecamacho on Wed April 10, 2013 12:06 PM User is offlineView users profile

The current compressor in the car is a Denso 10s17c, it's identical to the OEM one that came out of the car. we charged it to 1.3 lbs with our brand new RobinAir 34788h machine. The pressures dont change at all with differences in RPM.

TRB on Wed April 10, 2013 4:55 PM User is offlineView users profile

I have had issues with a few after market expansion blocks. Try an OEM block and see what happens.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

iceman2555 on Wed April 10, 2013 5:33 PM User is offlineView users profile

Agree with TRB on the TXV. Some of the aftermarket valves are not the correct 'tonnage' and this can contribute to the problem you are experiencing. The evap should have been flushed....this is where all the lubricant tends to 'settle'. Too much lube can inhibit heat transfer and actually become a restriction within the system resulting in low cooling efficiency. Go with the valve first. Be sure to charge the vehicle by weight...not pressures (bad move). Repost results.
Oh, by the way...the compressor does not cool the car. Never has...never will.
The temp drop across the condenser is too low also...if the measurements are correct....taken with a good thermo and touch probes.....not some TOY RAY GUN.

After re reading the post. The statements concerning the condenser...you stated pressure...did you mean temperature....and the inlet is cooler than the outlet.....sounds like a problem with the condenser cooling system....the condenser should DROP temp/pressure not gain. is your refrigerant pure....was it in small cans....what brand and where was it purchased. Do you have an identifier to determine purity of your refrigerant. 95 degrees does not equate to 125 psi. The compressor outlet temperature at this ambient temp should be app. 130/140 degrees and this would equate to app 210-235 psi. Consider the average temp drop across the condenser.....say 25 degrees at idle...max cool...high blower...doors open.....the posted pressures are not valid.
The TXV could be wrong...but it appears that the system is not fully charged.

Was the vehicle charged with a 2788 spec recharge machine...or by some other method.

THE #1 DIAGNOSTIC TOOL FOR DETERMINING AC SYSTEM PERFORMANCE CONCERNS OR PROBLEMS IS KNOWING EXACTLY HOW MUCH REFRIGERANT IS IN THE SYSTEM !

Cans and pressures are not gonna get it.

I do not think there is sufficient amount of refrigerant in the vehicle....or there is a serious restriction.... to cool the eavp...thus the high low side pressure and the lack of sufficient high side pressures. The compressor is not able to produce sufficient pressure/temp to make the condenser function as it should. Get it charge correctly and re post.



Let us know more.....

Good luck

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

GM Tech on Wed April 10, 2013 8:08 PM User is offline

Overcharge it a pound and see what it does--

and your scale may need calibrating on your machine

-------------------------
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......

josecamacho on Wed April 10, 2013 8:33 PM User is offlineView users profile

Update: Today we flushed the evaporator, suction line and liquid line, still no change. tomorrow I have an OEM TXV I'm going to try.

Heres the weird part: If we disconnect the condenser fans the high side pressure goes up to around 200 psi and the system begins to cool.

I'll check on calibrating our a/c machine. We have an older White Industries 3R machine i can also use. I dont have a good thermometer with touch probes, only an infrared thermometer gun.

The sugguestion about overcharging is easy enough. I'll try that tomorrow. Updates to come. Thank you all.

GM Tech on Wed April 10, 2013 9:12 PM User is offline

I still don't think you have enough charge in it-- as evidenced by the head pressure with no fans on-- it should be hitting 400+ sitting still and cutting off for high pressure.....

yes use another machine........see what happens...

-------------------------
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......

bohica2xo on Wed April 10, 2013 9:15 PM User is offline

The temperatures you list for the condensor inlet & outlet indicate there is nothing going through it. Or your non-contact thermometer is measuring the fan shroud / body panel etc.

Feel the inlet & outlet tubes from the condensor to be sure.

Try another gauge set. Tolerance stack up in connectors can lead to testing service hoses rather than systems.

Would not be the first time a whiz-bang automated machine failed to load the correct charge either. Doors open, cabin fan on highest speed. 2500+ engine RPM. If you still have those pressures I doubt there is really 20 ounces of refrigerant in the system.

B.

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"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.

NickD on Thu April 11, 2013 6:26 AM User is offline

Just doing a brief net search with that 10s17c number, everybody is using it, even a 24V Caterpillar. But adding a 2003 Cadillac CTS to that number really shortened the search.

If this is the problem, I don't know.

Besides blocking the output and charging the input with about 150 psi worth of air and dipping it in tank to check of leaks. Can also jury rig a pressure gauge to the output, and with most compressors should be hitting around 100 psi just by hand turning it. Takes about ten minutes to do this, do I sound paranoid? Really not, the way things are going today, don't know what in the hell you are buying, and its a lot of work on your own time to install these damned things. In effect using the vehicle for the test station only to find you purchased a piece of crap.

Some come precharged with oil, don't know why they do that, an extra operation to drain it, and put the correct stuff in. And that goes along with getting rid of that oil from the rest of the system.

With a TXV, and run 30 PSI through it, dip the capillary tube in ice water, it better slow down. Ever see those signs all over, no return on electronics? Can't count the number of times I had to return this stuff, just tell them they sold me a piece of crap and why.

josecamacho on Thu April 11, 2013 2:56 PM User is offlineView users profile

Okay this morning I, checked the calibration with the provided weight and it checked out good.

I installed a genuine Denso TXV I got from my Cadillac Dealer. Everything looked promising until the condenser fan came on and the pressures when to shit again. High side around 125, low side around 70psi. I then added another pound of r134a and the high side went up to around 200 but the system did not cool, it did force the condenser fans to run on a higher speed. It's about 75 degrees here in phoenix, I know it sucks to try and diag a/c when it's relatively cool out.

I recovered the refrigerant with our older AC machine, a White Industries 3R model 1090st, and confirmed that the scale on the new Robinair is accurate.

I don't want to sell the customer an evaporator (the only serviceable part not replaced yet) unless I know it'll fix it. It calls for 7 hours of labor and requires removal of the dash. I tried blowing through it a couple times already but the location of the ports makes it impossible to gauge air flow. Any other sugguestions?

mk378 on Thu April 11, 2013 5:57 PM User is offline

Blocked evaporator would pull the low side way down. It's not that.

This is very strange if it's not the TXV.

Where exactly are the high and low ports relative to the other components?

Edited: Thu April 11, 2013 at 5:58 PM by mk378

GM Tech on Thu April 11, 2013 6:25 PM User is offline

I've seen similiar events as yours- but only twice- when evaporator was built wrong- it had no passes- flow was just in and right back out again- BUT this only occurs on new cars under warranty- can't believe it would go unnoticed for ten years! in Phoenix! Face of evap would be warm- would be nice if you could get in there (remove blower motor) and feel the face- see if it is cool on one side or not at all.

The evaporator tubes have a notch on them to show direction to be mounted- there should be about 5 tubes south, 5 tubes north and then 5 tubes south again and out- there has to be two tubes (No. 5 and No. 10) which have a blank end so flow is directed through the body of evap.

Has this car been in Southwest all its life? or in Canada where a bad evap may not get noticed....

-------------------------
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......

josecamacho on Fri April 19, 2013 5:38 PM User is offlineView users profile

Update: We decided to take the system apart again and test for restrictions, while holding the discharge hose the technician noticed a rattle inside the hose. The hose was cut open to reveal that the barrier liner (the inner liner) was collapsed. Apparently the previous failed compressor's debris damaged the hose and the liner acted as a giant parachute inside the hose. The customer picked it up today and the cursed car is finally out of my hair. =)

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