AC compressor

[brmurph]

Ever since the dealer replaced the compressor a couple of months ago on my 98 Deville I can now feel when it turns on and off. It feels like transmission chugle but I don't think it is as it goes away when the AC is turned off. Over the weekend I replaced the multi acc belt (and plugs and wires BTW) and noticed that the compressor clutch has a lot of play in it while turning (maybe 1/8 " or so). I now think this might be causing the problem but the dealer said this is normal (of course).

Anybody know if this is normal? I use to sell autoparts and I never noticed the clutch loose like this but that was 15 years ago.

Thanks.

[Scotty]

We have had a spirited discussion about this recently on another thread.

Its normal or probable that you are feeling your AC compressor kick on and off, I feel mine ever so slightly especially in OD when the car is laboring up a hill.. You probably are feeling it more now because your compressor clutch is engaging without slipping OR the design of your compressor clutch IS different and doesn't have the rubber insulator that your old compressor had. I wouldn't worry about it...

I don't know about the looseness you are talking about as long as its not side to side or as long as the hub isn't loose due to bearing wear

[sal.carceller@cox.net]

Ever since the dealer replaced the compressor a couple of months ago on my 98 Deville I can now feel when it turns on and off. It feels like transmission chugle but I don't think it is as it goes away when the AC is turned off. Over the weekend I replaced the multi acc belt (and plugs and wires BTW) and noticed that the compressor clutch has a lot of play in it while turning (maybe 1/8 " or so). I now think this might be causing the problem but the dealer said this is normal (of course).

Anybody know if this is normal? I use to sell autoparts and I never noticed the clutch loose like this but that was 15 years ago.

Thanks.

I agree with Scotty, this is most likely normal. I feel my AC Compresor turn on and off as well. Also keep in mind that you had it replaced for a reason and most likely the old one was not operating at peak compresion near the end of it's life. So now you have a new one that does work as designed and produces much higher compresion than your old one. In addition your AC system is now fully charged causing the compresor to really work and eat up a few horse power.

[brmurph]

Just seems odd that it never happened before (had the car since 35,000 miles, now has 93,000). I have felt this on other cars but never my caddy. Also it feels so different then other cars I have owned (kinda like what transmission chuggle would feel like). It is very annoying when the car stumbles every 15 - 30 seconds or so.

Also the AC seemed colder before the replacement compressor.

Thanks.

[Scotty]

Now THAT is a different story! I just replaced my AC compressor and it freezes me out now. What was wrong with your AC to require compressor replacment?

If it is not cooling as before its possible that you have a problem. Maybe too much oil? Too much oil would give you a more pronounced engagement and less efficient cooling.

Lets see what our AC experts say about this.........

[brmurph]

I may have mispoke a little. The compressor worked fine and was cold last year, this spring is when the trouble started (not cold at all). The dealer diagnosed the problem as a bad compressor and replaced it under my extended waranty. It is now cold but not as cold as the original, sometimes over 60 degrees at the vent will idling, ambient temps in mid 90's but normally between 48 -52 down the freeway.

I am sure it is probably cooling within specs, the real problem is the chuggle or stumble every time the compressor starts up.

[sal.carceller@cox.net]

It is now cold but not as cold as the original, sometimes over 60 degrees at the vent will idling, ambient temps in mid 90's but normally between 48 -52 down the freeway.

48 - 52 is not cold enough while driving down the road. If the AC is working at 100% the duct temp should be 35 - 42 with 90 outside. I suspect the AC is not to spec. I would expect temps lower than that.

[brmurph]

It is now cold but not as cold as the original, sometimes over 60 degrees at the vent will idling, ambient temps in mid 90's but normally between 48 -52 down the freeway. 

48 - 52 is not cold enough while driving down the road. If the AC is working at 100% the duct temp should be 35 - 42 with 90 outside. I suspect the AC is not to spec. I would expect temps lower than that.

I like your thinking (35-42 sounds much better to me :-) Are there any tips to help get the AC down to this range that the tech may normally not do to save time?

[Ranger]

There is some relavent information in this post. Maybe it will help.

http://caddyinfo.ipbhost.com/index.php?sho...uct%20temp&st=0

[brmurph]

I just dropped the caddy of at the dealer for an oil change and to check the AC. On the way the coldest my AC got was about 50.5 degrees (ambient temp about 94). My wife picked me up in her Volkswagen Cabrio convertible 45 minutes later and her AC got down to 38 degrees (ambient down to maybe 91). Both systems were checked at the vents with AC on full blast and recirculation on.

Again the biggest problem I have is the chuggle when the compressor comes on, I just thought the VW being over 10 degrees cooler then the Caddy was interesting.

BTW this is in Austin Texas, somewhat humid but not that bad.

[sal.carceller@cox.net]

I just dropped the caddy of at the dealer for an oil change and to check the AC. On the way the coldest my AC got was about 50.5 degrees (ambient temp about 94). My wife picked me up in her Volkswagen Cabrio convertible 45 minutes later and her AC got down to 38 degrees (ambient down to maybe 91). Both systems were checked at the vents with AC on full blast and recirculation on.

Again the biggest problem I have is the chuggle when the compressor comes on, I just thought the VW being over 10 degrees cooler then the Caddy was interesting.

BTW this is in Austin Texas, somewhat humid but not that bad.

The VW temp sound much better. No matter what type of car the AC should get below 40 degrees if working properly. Scotty mentioned earlier that you may have to much oil in the system and this does happen often when they replace the Compresor. But I wonder if the compresor is really the trouble. Could be that something else is wrong and they replaced the wrong part, hard to tell. One thing for sure 50 degrees at the ducts just is not going to make you happy in Texas! Take it back and have them report what the presure number are on the High and Low side of the system. Also, what freon are we talking about here R12 or R34?

By the way an oil overfilled system is really bad and could cause pre-mature compressor failure since large amounts of liquid oil coming back into the suction side of the compresor could really lock the compresor up and the fact that you really feel it coming on would have me questioning this. The only person who knows how much oil was added is the tech that did the work go back and ask him. I have replace/fixed many AC systems and if I do a compresor change I always try to catch/empty the failed part of any oil it may have into a measuring cup and then add that amount + about 10-15% more.

[KHE]

A 1998 Deville has a refrigerant capacity of 2.0 lbs. of R-134a. When replacing a compressor, If less than three ozs. of oil are drained from the compressor, three ozs. of oil should be added to the replacement compressor. If more than three ozs. of oil is drained from the old compressor, an equal amount of oil is to be added to the replacement compressor.

As long as the system was evacuated for the proper amount of time, I don't know what a tech. would have done to save time.

What did you find out at the dealer?

[KevinW]

Is the replacement compressor identical to the original? The lack of a torque cushion in the clutch might help to explain the different engagement characteristic.