Lesabre A/C compressor

[Gocart879]

Hello, recently my ac compressor has been clicking on and off quite rapidly, however when i jump out the pressure switch, the compressor will stay running. i did a test and let the jumper in for about 5-6 minutes and the compressor stayed running quietly the entire time. the vehicle was cold inside as the temperature outside was about 85-90, the vehicle was very comfortable. i need to know if a compressor runs all the time if the unit is low on freon or even high on freon, i believe my pressure switch is the cause however you can never be sure so i want to make sure. thankyou for your help.

[formzy]

Hello,
Just wondering what year your LeSabre is? Later models have the v-5 compressor that doesn't cycle but runs continous. Is it late 80's? Then you have a pressure cycling switch that will let the compressor cycle on and off as needed. Usually a rapidly cycling compressor says it is low on charge. When you by-passed the switch this makes the compressor run steady which is bad for too long when low on charge as this is the only way the compressor receives lubrication from the flowing vapor which carries the oil. If yours is cold (Accumulator cold) inlet and outlet of evaporator lines aprrox. same cold temp. then I would guess that your cycling switch is bad. You can replace this without discharging the system. Do you still have the old r-12 or has it been converted to r-134 ? Not knowing the year of the car doesn't give a full picture of what's going on. Good Luck!

[Gocart879]

yes it is an 89, and it is still r-12. How can i check the things u mentioned to see if the cycling switch is bad? the compressor ran constantly for 5-6 minutes without shutting off when i jumped the switch and i heard no noises or problems occuring. i would like to know how to see if the lines are both same the temperature. thankyou for your help.\
Gocart><

[Flatrater]

If you jumper the pressure switch and the compressor stays running, then I would say you have low freon level.

Replacing your switch will be a waste of time and money for you since this will not cure your problem.

BTW a well working AC system the low side line will be cold to the touch and the high side will be hot.

[Gocart879]

OK, now if i can find some duracool or r-12 equivilent will that be sufficient?

[formzy]

You can check the inlet and outlet tubes of the evaporator (attached to the accumulator and liquid line in the back right rear firewall area). You "feel" the temps. by hand. They should be cold and somewhat similar in temperatures.
In response to flatrater- gocart said he had good temps. leaving me to believe that the refrigeration aspect was good or close to normal. Bypassing the switch will let the compressor run contiously as I said before. (Whether you have high or low charge)The switch shouldn't rapid cycle the compressor if the charge is good. Do you know anyone with a set of gauges? You should run about 30 lbs. on the low side and 2.2-2.5 ambient temperature on the high side. I've converted a few to r-134 and they have worked well. R-12 is hard to get and very expensive. If you just need topping off then I would stick with the r-12.

Look at a shop manual if available in the library to see the component locations I spoke about. I own a '90 Lesabre and just replaced a leaking evaporator core(very common on these cars) 3-4 hours each way. Converted it to r-134 with my guage set and added 24oz. or r-134. The 85% conversion figure I feel is too high and will blow the shaft seal on the compressor. R-134 runs at a higher head temp. Just letting you know this info in case you decide to convert down the road. Try the switch replacement(it's cheap enough) first. Also get someone to check the pressures before that if possible, it will tell you allot about the conditon of the system. Hope this Helps!

[HotZ28]

Originally Posted by Gocart879

OK, now if i can find some duracool or r-12 equivilent will that be sufficient?

There has also not been any single refrigerant or blend that is a direct drop-in for R-12 of any other CFC. There is always the need for some retrofitting of the system. Finally, most blends and their lubricants are not compatible with the existing R-12 system and will require separate service equipment. Recharging a blend is also quite different. When using blends, you can not just top-off a system that has a refrigerant leak. Rather, you must replace the entire refrigerant charge. Do yourself a favor and avoid blends. Remember, any refrigerant with the 400 series number is a non-azeotropic blend, such as R-401A or R-401B, which are supposed to be substitutes for R-12. These refrigerants may have fancy trade names and even have 12 in their trade name, but if the official ASHRAE designation begins with R-4__, or R-5___, it is a blend!

Lubricant Change-Over
In a retrofit application, one of the most important system changes is the lubricant. The lubricant used in a system should always be identified on the unit because of potential lubricant incompatibilities. The mineral oil lubricant used with R-12 systems will not mix with the polyalkylene glycol (PAG) or polyol ester (POE) lubricant used in R-134a systems. (As little as 1% mineral oil will contaminate a POE oil.) HFC-134a still carries some concern about compatible lubricants. Polyalkylene glycols (PAGs) mix properly with HFC-134a at low temperatures but have upper temperature problems, as well as incompatibility with aluminum bearings and polyester hermetic motor insulation. Ester-based synthetic (POE) lubricants for HFC-134a resolve these problems but are incompatible with existing PAG or mineral oils.

I happen to have a friend who is a small independent refrigerant supplier, and have access to the “Virgin” R12 (12 oz cans to 30 lb cylinders), if anyone needs some. You must be EPA MVAC 609 certified to purchase it. This is not an advertisement, however if you are certified & interested, send me a private message.