Year: 2000
Make: Cadillac
Model: Escalade
Engine Size: 5.7L
Refrigerant Type: R134a
Ambient Temp: 80
Pressure Low: 40
Pressure High: 200
Country of Origin: United States
I live in South Louisiana. I am having some odd problems with a vehicle I purchased about 2 months ago. When I got it, it would take a couple minutes to start cooling, then it would cool down to around 40 deg F inside (in 70 deg weather) then stop cooling for a couple minutes until it gout to about 65 deg F inside then it would start cooling again until around 40 deg F and so on and so on. I had added a 12 oz can of coolant and it improve slightly for a couple days and then went back to what it was doing before. This past weekend I went meet a friend out of town who had a vacuum pump and drained the system completely and held a vacuum on it for and hour or so. It pulled 30 in vacuum and after an hour or two it dropped to 25 in vacuum. I then refilled the system with synthetic "artic freeze" R134a coolant. I have dual AC units and it called for 3 lbs 8 oz freon which works out to 56oz. We put in about 54 oz and it seemed to be cooling decent. It got down to around 50 deg F after idiling for 10 minutes or so in the driveway. The high side got up to around 200 in the 80 degree weather and the low side was around 40. I turned the vehicle off for a couple hours and then got back in it later to head home. It started the same senario all the way home cooling down then warming up, cooling down the warming up. I went to the store to get a can of freon to top it off (since it was technically still low) and immediately after pumping some freon in, the clutch engaged and it began cooling well and did the way home for 5 minutes or so. I thought I had cured it until last night when I went to class and it didn't cool until after 5 minutes or so. I just changed the AC relay in case that was bad but its still doing the same thing. Can anyone please provide feedback on what I should do next?
Did you happen to check the Orifice tube wile you had it empty of refrigerant? Are all of the mode doors working in the in the selective modes as requested? (Floor, Vent, Defrost, Hot/Cold and Fresh air/Recirculation modes) You stated it dropped in Vacuum, did you leak check the system after charging?
I had run some UV dye in it when I added freon the first time (before I vacuumed it out) but could not find any leaks under the hood or in the condensor. It may have a small leak but if it could hold thru the summer, I would be happy. All vents work properly. I did not open the system to look at the orifice because I thought it was a moisture problem but if I can't find the problem soon, that might be the next place look.
Intermittent cooling you should think clutch gap first. Catch it when not cooling, pull over and see if clutch is engaged. Bang on the clutch plate if it's not, if that makes it pull in it means you need to reduce the gap.
Is there a standard gap that I should have? I did not think of that possibility. When it does cool, it cools well. I can usually get the inside temp 35-40 deg F cooler than the outside temp.
I tapped on it when it was not cooling and it did not make it engage. Sometimes when I start driving, it will take up to 10-15 minutes before it will engage the compressor clutch. Just this weekend, I drove 10 miles with the AC on high and it still hadn't started cooling. When I checked the low side pressure, it was 80 psi. After another 6 miles or so, it started cooling and then cooled down to 45 inside with a outside temp at 72 before it stopped cooling again just before I got where I was going. Could this be the trinary swith?
You have an electrical issue, when not cooling, jumper the a/c relay, does compressor come on? This cuts the diagnostics in half- if no a/c, then the problem is downstream towards the compressor, if a/c works with relay jumpered, then problem is upstream, most likely an input device.
A scan tool will give you input and output status- you may need to find someone with one to pinpoint problem.
Meanwhile, when a/c is inop, you can wiggle every sensor wire, and compressor wires you can find.
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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......
I would follow GM Tech advice with the checking of the electrical. unplug and plug in all switches out side in the engine area to make sure you have good contact in all terminals. Some times the Low pressure cycling switch located on the accumulator is the problem, tap on it and see if it engages wile the engine is running and the a/c is requested. Hope this helps and good luck!
I just had same issue on a 2003 Suburban (same vehicle as yours) the minute I touched the a/c relay, the compressor came on.....It had poor contact in plug connectors- swapped it with horn relay, just below it, and cleaned and lubed legs...all is fine now.
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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......
I had replaced the AC relay early on and it did not change anything about the situation. I will try wiggling the connectors and let you know what I find. Thanks for the input.
OK, I put the gauges on it when I got home. It is 82 deg outside. The low pressure side started out around 45 psi and cooled until it got down to 25 psi when the clutch unlocked and the low pressure went to 75-80 psi and would stay there for what seemed like 3-4 minutes then it engaged again and the pressures repeated. The high side during this started around 220 psi and got down to about 190 psi when the low side was around 25-30. With the low side under 30 psi, the inside temp got to 40 deg F thru the vents. When the clutch disengaged, I unplugged the pressure switch on the dryer and jumped a wire across the circuit poles. The clutch did engage. Any suggestions why the clutch would stay disengaged so long long? What is my next step?
3-4 minutes at 75-80 psi suction means it's time for a cycling switch-- replace that puppy!
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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......
Could that be the entire problem?
Very likely- most likely, yes likely.....run Forrest run to Autozone, Advanced, Napa, O'reillys or wherever you like best and get a cycling swich-- sometimes called low pressure switch, or evaporator freeze protection switch as well.
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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......
But I will have to evacuate the system? If I have to go that far again, I'm gonna replace the dryer and orifice tube to make sure that I don't run into anymore issues.
No need to evacuate. There is a valve under the switch that will close off when you unscrew it so the system stays charged. Put a new o-ring on the fitting, install new switch (hand tighten only). Check that it is not leaking.
The switch should restart the compressor around 50 psi, not 80.
Edited: Fri April 08, 2011 at 9:05 AM by mk378
Really haven't kept up with Caddies except to note the depreciation is worse than ever. Old 92 has that failsafe pressure switch, suppose to be remained closed all the time except during subfreezing weather and opens if the pressure drops below 8 psi. But that in conjunction with the ambient temperature does not generate a code if it opens. But with AC weather will flash the service AC now light on the dash if it opens. By playing with buttons on the climate control and watching the fuel mileage display, tells you exactly what pressures you have, but in degrees C rather than psi. But all the same thing.
Are you getting error codes? Do you need a GMTech II scanner to do anything? I know on my 92, would have to recover to replace that switch, and really no cycling switch per se, uses all thermistors.
One thing I have learned, really need a shop manual, first car with automatic climate control was a 70 Buick Rivera, but back then, was only four bucks including postage.
Hey Nick-- that was my first thought- Caddy - thermistors, digital code readouts, etc...but this is an ESCALADE-- basically a suburban- made on truck platform, so it the name Caddy does not apply IMO...it is merely a dressed up Suburban truck and uses all its controls..
So you have to think Chevy Truck when dealing with this post.
Very similiar to the old X-bodies- Caddy had one too as I remember-- wasn't it a Cimarron? Kinda cruel to use the Caddy name to sell a truck.
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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......
Actually, it's a fancy Yukon according to the reports I read. Obviously something was not right with them because they debuted in 1999 & 2000 models but stopped and did not produce a 2001 model at all. The first 2 model years had the vortec 5.7L. When they reaappeared in 2002, it had the 5.3L just like the Tahoe & Yukons. The Tahoe & Yukons offered the 5.3L starting in the 2000 model year. I was looking for a Tahoe when I bought this one but couldn't find a nice one with 4wd.
Anyway, I changed the cycling switch on the dryer and drove it back 3 miles from Autozone. The ac was working fine on the way back but I am gonna reserve the right to say it is completely fixed cause it does work well at times. I will get back to you after the weekend with a report on the progress.
Suppose if like the trucks, cycling switch switches the full load of the compressor coil. Kind of think about adding a relay to lessen that load, but if it worked for ten years, not worth the effort.
Hmmm, that reminds me to pull that dash apart in my Cavalier, mode door is binding in subzero weather, but not a problem now with warmer weather.
With warmer weather, start to think about thermal cycling of the engine between 195-232*F due to that stupid using the ETC for fan control. But a major modification, think I will just drive at night in much cooler temperatures. Or just park the car until next winter.
NickD- you're living in the 80's trucks have used a/c relays now for at least 20 years.....his is in his underhood fuse box.....
Be Gentle now......
-------------------------
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: Fri April 08, 2011 at 3:07 PM by GM Tech
Well, this truck has a BIG fan clutch and it rarely runs above 200 deg.
I am happy to report that my AC has been cooling consistantly since changing the cycling swith on the dryer. I am glad that it was cured by a $15 switch because I was not looking forward to spending several hundred dollars on changing other components. I would like to thank all of you who commented and helped me figure this out. Your help is GREATLY appreciated.
It's nice to win one once in awhile-- the Stealership would have given you the same results, but with a new compressor, then they would have found the $15 now $75 switch and you would have been none the wiser, just $900 lighter in the wallet.
Thanks for responding.
-------------------------
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......
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