QuestionQUESTION: Sir,
During my troubleshooting of my 1997, Pontiac Sunfire GT, 2.4 Ltr. I discovered that the refrigerant level was low based on using my manifold gauges. I checked for loose connections and discovered one at the accumulator/drier. I tightened the loose fitting. I then evacuated the system for approximately one hour and then I checked to see if the vacuum held. I let it set for 10 minutes and there was no drop in the vacuum. Based on the loose connection discovery I added one can of 8 ounces of refrig/dye/stop leak. I then continued to service the system with 2 cans of 12 ounces of 134 refrigerant.
The specifications call for 24 ounces for a complete charge. I know by using 12 oz cans it is easy to be off on the correct charge. I factored in a 2 oz lose for the hoses/manifold system, 1 oz per can x 3 cans. The math came out to -5 ounces from the total of 30 ounces. Which equals 25 ounces. If it were a perfect world I would only be over the specifications by 1 ounce. Long story, longer, the a/c system worked great for approximately 3 weeks. When it quit cooling, I looked for the UV dye evidence. I found dye around the mating portions of the compressor. Everywhere else had no UV dye evidence, I even checked the condensation drain on the evaporator.
I recently purchased a reman compressor from Advance Auto, with the new orfice tube/receiver dryer. I have yet to install them. I plan on doing this after I hear from you. I also plan to flush the evaporator and any hoses that do not have a muffler.
I have had great success with my son's ford ranger, 30 ounces system spec. I used three 12 ounces cans of R 134. Using the same math procedure. Additionally, to maximize the charging of the system, I placed the refrig cans in hot water during the charging procedure and I also hosed down the condenser to help the process of getting the most refrigerant from the cans. And it worked great.
My question is regarding a more precise charging procedure at home. Would using a electronic weighing scale help in this process of using 12 ounce cans?
The compressor on the Sunfire is it a continuous run compressor or should it cycle like my son's ford and my Honda?
What did you think about how I serviced the Sunfire before I discovered the UV dye evidence? Was my logic flawed regarding using two 12 ounce cans and one 8 ounce can to equal the 24 ounce charge?
Your help is greatly appreciated.
Sincerely,
Richard Webb
ANSWER: Hey Richard,
You could use a electronic weighing scale just make sure it can precisely weigh ounces to get the proper charge. I haven't used the weighing scale myself because I have only used the a/c machines at my shop. The a/c compressor on the sunfire should cycle on and off. The way you serviced your a/c system sounded pretty good to me considering you did it at home, the only thing I don't recommend is that stop leak stuff because I've seen it gunk up compressors and completely kill them. But other than that it sounds like to have a pretty good knowledge of servicing and repairing your a/c system.
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QUESTION: Sir, Thank you for your quick response. I have decided not to use the stop leaks as a means to having the math workout as far as the specifications. I will either buy a scale or put all the parts in myself and then evacuate the system. Then I'll take it to a local shop and have them service the system.
What method does the '97 sunfire use to cycle the system off and on?
The systems specification call for 9 ounces of PAG 150 oil. I plan on flushing the evaporator as a precaution and any hoses that don't have a muffler installed.
How much oil do I add to the system since I am not replacing the condenser?
Is it best to add half of the oil to the compressor suction side during the install and the other half to the accumulator/receiver dryer.
I have done some research on methods to protect the compressor and I have read that GM recommends a suction screen installation on the pump and an inline filter. What do you think of those systems? Additionally, where would I go to purchase these items? Thanks again for your help. It is greatly appreciated.
Sincerely,
Richard Webb
AnswerThe system uses a pressure switch to tell the compressor to cycle on/off and if the system calls for 9 ounces that will be enough for the system and about the suction screen if GM recommends it I would install it as insurance for the new compressor, those aren't cheap. You should be able to find that screen filter at the dealership parts department, if not they should know where to find it or be able to order for you. The installation instructions for the compressor should tell where to add the oil but if not I add it to the compressor so it is well oiled and a lower risk of burning up during the break in period. Be sure when you have the a/c system serviced to tell them you have already added the oil so they don't add anymore and over fill it.
