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AC cadillac question


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da324
User

Jun 26, 2019, 1:53 PM

Post #1 of 18 (349 views)
  post locked   AC cadillac question  

I have a 1996 Cadillac Seville, 110k. Last year I replaced the orifice because the air was barely blowing. It was filthy, but expected for as old as the car is; I also changed out the accumulator. I did a vacuum on the system and it held neg 30 for well over an hr. Had a friend put in 32oz of refrigerant which is what the car calls for. It was blowing cold and hard. I took it home which was 6 miles and parked it. It's not a daily driver and Florida had a cool winter last year, so I didn't use the ac again until recently. I got a readout on my instrument panel stating refrigerant very low. I've since bought some gauges and hooked them up and both sides were barely registering. I found what appeared to be a leak on the high side service port. There was green oil everywhere inside the cap, and, gummy black residue below the high side port on the rail. I assume this is oil also. So, I replaced the whole high side port valve since I could not get the Schroeder valve out. I vacuumed the system down again and let it sit for about an hour and a half, needles on gauge pegged at neg 30. I put in 32oz and she took it no problem. When I first got in the car, the vent read 50°, not what I wanted, but not bad. The gauges read 45 psi low and 230 psi on the high side. For the temp here today, that was spot on. I waited an hr and took it for a drive and it never went below 60° at the vent. Gauges still read the same. When I rev the engine to 1200 RPM she drops to about 40 psi on the low side, which is fine. My question is, what could be keeping her from getting a colder reading at the vent? Sorry for the long post, but I wanted to give as much info as possible with the hope that someone could steer me in the right direction. Thanks.


Tom Greenleaf
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Jun 26, 2019, 3:20 PM

Post #2 of 18 (332 views)
  post locked   Re: AC cadillac question  

Fast read - sorry. Clogged and black oily means it croaked the compressor. No short cuts out it took out the condenser too nearly for sure and maybe more.
If you want it to work, needs the works - total redo after flush.
Green stuff was dye some factory ones had it. Leaking Shrader you just loosen, hear a spit and gently snug up most quit that.
Strong maybe: If refrigerant low on these it should say to disconnect battery to allow grace time for compressor to get power it's shut down or should have by now or will.
No low pressure cut out I think all those use a "thermistor" instead but acted like a pressure switch. Can't and don't jump it.


That age is original all leak some if orig. My habit disable compressor for off season it will try too long and burn out compressors it still comes on when cold you just don't notice and oil can't circulate with low refrigerant. You'd hear it knocking but not those too sound insulated.


Good luck but you wont win it's all or nothing. Procedure is above locked for "Catastrophic Compressor Failure" applies to this near certain,


T



Hammer Time
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Jun 26, 2019, 3:54 PM

Post #3 of 18 (325 views)
  post locked   Re: AC cadillac question  

I hope you're kidding about the temp. Assuming you had it on high blower speed, 50deg at a standstill is damn good.

The low side pressure corresponds very closely to the evap temp. You have 45PSI on the low side so that puts your evap temp at about 45 degrees. Only losing 5 degrees from evap to vent is pretty good.

The other thing to consider is whether you had it on recirculate or not. Re-cooling inside air is much easier than 90 degree outside air.

Also note that if your orifice was plugged up, that means the compressor or dryer is coming apart internally and you have more problems on the horizon if it's the compressor which is more likely.



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da324
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Jun 26, 2019, 4:29 PM

Post #4 of 18 (320 views)
  post locked   Re: AC cadillac question  

Thanks! Yea, it just didn't feel all the cold at that temp because my other cars register low 40's. My son drove it to work which was further than my test drive and said the temp was 44° at the vent while moving and 60° when he stopped at lights. It was a hot one today, so maybe we're all good. If I choose to take a look at the new orifice and it's dirty again, I guess I would replace the compressor? If so, do you think I should change the condenser out with it? The accumulator was replaced with the orifice, so guessing it's still fine? Thanks again for the help.


Hammer Time
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Jun 26, 2019, 4:51 PM

Post #5 of 18 (313 views)
  post locked   Re: AC cadillac question  

I suspect your other car may be an expansion valve system and not a CCOT. That would justify the colder air.

On the compressor, yes if you end up changing the compressor, change the condenser also or you will just harm the new compressor.

Your pressures seemed a bit high so I would verify that the cooling fan is running up to speed. They use a 2 speed system. It may be the condenser to blame for that. If the fan isn't doing it's job, that would explain the compressor failure.

A shortcut to determine if condensing is the issue, feel the temp of the liquid line. If the system is operating properly, that line will be warm to the touch. If it is hot, the condenser is not doing it's job. If it is ambient temp, then there is insufficient flow in the system and you have a blockage, not likely in your case though.



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da324
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Jun 26, 2019, 6:56 PM

Post #6 of 18 (286 views)
  post locked   Re: AC cadillac question  

Thanks, the fan seems to be working fine. My son drove the car to work today and said it would hit 43° while moving, but would go to 60° when stopped. It was 97° and felt like 105° today; man was it hot! I appreciate your help and will continue monitor the system. Thanks again!


Hammer Time
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Jun 26, 2019, 7:00 PM

Post #7 of 18 (280 views)
  post locked   Re: AC cadillac question  

Those symptoms due tend to point to a weak fan when it gets that much cooler driving down the road. The only thing you are changing is airflow across the condenser.



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da324
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Jun 26, 2019, 7:48 PM

Post #8 of 18 (272 views)
  post locked   Re: AC cadillac question  

I have a dual fan setup, wouldn't my car overheat too if one of the fans wasn't working properly? I'll check tomorrow and make sure they're both turning. Thanks!


Hammer Time
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Jun 26, 2019, 7:56 PM

Post #9 of 18 (266 views)
  post locked   Re: AC cadillac question  

Just turning may not be enough. Motors get slower with age. The AC is far more sensitive to fan power than the engine temperature is.

All your facts point to insufficient airflow across the condenser

ie;

Failing compressor
higher than normal pressures on both sides
Considerably colder temps when the car is moving vs stopped

Your problem is subtle, not extreme but that will have an effect over the long term.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Hammer Time
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Jun 26, 2019, 8:03 PM

Post #10 of 18 (259 views)
  post locked   Re: AC cadillac question  

I see you're in Clearwater. I'm in Palm Bch County so I deal with this type of stuff all the time and I know what you're up against.
Ideally, your high side should be under 200 at idle after the system is equalized. Pressures over 250 constantly will take a toll on the compressor over time.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



da324
User

Jun 26, 2019, 8:10 PM

Post #11 of 18 (257 views)
  post locked   Re: AC cadillac question  

Is there a way to check the fans for proper output? The car is 24 yrs old and in in great shape, but that makes a lot of sense. I really appreciate your knowledge, thanks!


Hammer Time
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Jun 27, 2019, 2:42 AM

Post #12 of 18 (234 views)
  post locked   Re: AC cadillac question  

There is no real clear test. Most of it is based on the symptoms. You could spray a mist of water on the condenser while watching what happens to the pressures. A big drop in pressure means you are losing out on the efficiency of the condenser. There will always be some difference but a big one indicates a problem. It's a judgment call as to the actual cause. The most telling test is the road test. When you see a dramatic difference between driving down the road and holding it at the same RPM sitting still, that is an indication that you are benefiting from increased air flow across the condenser and you should look for a way to improve that.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jun 27, 2019, 2:44 AM)


Tom Greenleaf
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Jun 27, 2019, 5:14 AM

Post #13 of 18 (221 views)
  post locked   Re: AC cadillac question  

Back and some observations on this that MAY help: Long first post - fine but was stuck on a clogged "o" tube isn't a good sign for compressor. Question is can it be fine now? I can't be certain.
Next is the condenser. The two thing, pump and condenser's ability to exchange heat just wildly matter. This is a few years into OE 134a a gas that is more fussy, more able to leak than the prior R-12. So the condenser is thinner to exchange heat fast a furiously but more delicate inside and outside. Can't flush those but seems it's not totally clogged INSIDE it works at all.
Outside: I'm in New England vs FLa. What matters to these locations: Less humid here but can be air temps much hotter just not so long. Debris is a given here - dirt, small rocks bust thru these weaker condensers plus they use road salts here that metal rust out fast - game over for either. You both are more likely for those (sorry for the words" (love bugs) clouds of splattering bugs that eat thru paint, metal. IDK how you can get that splatter out of a condenser without harming it? That on the outside. There is the in between to consider as well unseen usually. IDK each approach - top or from underside need to look at least.
HT is right on with the water. It's going to work better than fans - that's a given and info also by how much. I see dramatic drop a lot more often normally just dryer air water evaporates faster so cools it plain cold useful to do at times assorted reasons.
This car exists so something went right. More surprise you were able to replace accumulator at all without twisting up the lines is shocking to me. They weld to one in no time here just a mist of the damn road salt not sea salts air 10x more corrosive.


Just that says volumes on what condition you have and can do with this vehicle at large.


One more "FANS:" IDK either how effective they are try to feel air, opened hood how much heat comes off but when closed hood heat is going down so not sure the test is that valid.
Second one more: Air shrouding for fans intact a must and also below an air dam really matters creates a vacuum behind it at vehicle speed sucking air down an out. If not right it blows backwards on some. That stuff matter not for decoration.


Carry on and win this,


Tom



da324
User

Jun 27, 2019, 8:19 AM

Post #14 of 18 (208 views)
  post locked   Re: AC cadillac question  

Thanks, I'll check that out.


da324
User

Jun 27, 2019, 8:29 AM

Post #15 of 18 (203 views)
  post locked   Re: AC cadillac question  

  My son just got his first job and the car will be used much more than it ever has been since I bought it in 2001. I do know that she doesn't like inactivity as minor problems pop up when I don't drive it for weeks. These bugs usually work themselves out after a decent drive. I've lived in Fl my entire 55 yrs and while there's not much to brag about here anymore, one good thing is that rust has never been an issue for me with vehicles. I live 6 miles away from the beach and a half mile from the bay. I did get under the condenser last night and saw slight surface rust on the bottom, but all of the lines going to and from were rust free. Air coming in is not being impeded, but I'll get a better look today and go from there. I just don't want the evaporator to go bad as the motor has to be removed to get it out, or, the body raised off the motor. I will not ever do that if it goes bad. The compressor and condenser I can handle if needed. Thanks!


da324
User

Jun 28, 2019, 5:25 PM

Post #16 of 18 (162 views)
  post locked   Re: AC cadillac question  

Thought I'd give you an update. My son says it's 42° driving, and 55° when he's stopped the last two days. Now, when he's stopped the RPM's as you mentioned are at rest, not the same as when he's driving. I sprayed some water over the condenser and didn't notice a noticeable drop. The condenser also looks very clean, no bugs, etc. all over it. Would low oil in the system make the temps change? Also, how do the fans cool the condenser when the radiator is in between the fan and condenser? Are they strong enough to pull air through both of them? I'll keep an eye out as he says it's very comfortable, and it has been nasty hot. Thanks again!


Hammer Time
Ultimate Carjunky / Moderator
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Jun 28, 2019, 5:31 PM

Post #17 of 18 (154 views)
  post locked   Re: AC cadillac question  


Quote
I sprayed some water over the condenser and didn't notice a noticeable drop.


Drop in what? If you didn't have any gauges hooked up to it, then you didn't check anything.

Yes, the fan is designed to pull through both of them. That's why the sides and bottom are usually sealed off, to force air through the condenser.

This thread has pretty much run it's course. we are just beating a dead horse now so I will be closing it soon.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



da324
User

Jun 28, 2019, 6:32 PM

Post #18 of 18 (146 views)
  post locked   Re: AC cadillac question  

I was just giving you an update. Sorry, I'm not a pro ac guy, that's why I'm here. feel free to close the thread.


(This post was edited by da324 on Jun 28, 2019, 6:33 PM)






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