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Automotive/92' CAMRY 300K A/C NOT WORKING

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Expert: - 7/2/2007


Question
Hi Ernie, thanks in advance.
  My question, when i bought my camry last year, the dealer re-charge it and after couple of month i notice the air is not cold?? i notice now that when i switch on my A/C nothing change, my RPM remain the same, my rad' fan won't turn, didn't hear any sound from the compressor ?? my Rad' Fan is working fine when it needed to cool the coolant. i would like to troubleshoot and find the problem.
i recentrly heard of DuraCool as being enviroment friendly, did you have any advise regarding using DuraCool and the Moisture remover and Sealent that come with it.
Thanks Again
 Calvin

Answer
First things first: a system which loses cooling ability within a month or two definitely has a leak somewhere, and isolating and repairing that will be your primary task.  As you have noted, the compressor does not engage, and will not engage under low- or no-charge conditions, as it is protected by a low-pressure inhibit switch that will keep it shut off when the charge pressure is inadequate.

Leaks can occur in joint seals such as connector O-rings, or can be corrosion-caused pinholes in the evapourator or in any other thin-wall metal part of the system.  They can be found using an electronic leak detector or a flame leak detector provided non-flammable refrigerants are still in use.  Future leaks can also be highlighted by adding a leak-detection dye to the charge installed in the repaired system.

My own experience with Duracool is quite new, and I have found it to be serviceable in getting the R12a system in my older Mercedes up and running.  Duracool is a hydrocarbon (HC) refrigerant, based on refrigeration-grade propane, and therefore it IS flammable.  This is of no consequence in the normal operation on the refrigeration system, but does require that the use of the HC refrigerant be clearly flagged by clearly visible label on the system, as its use means that flame-type leak detectors must NOT be used, and brazing and welding operations must be performed only after the system has been purged and evacuated (which is the best practice anyway).

Beyond this, my best suggestion is that you check out Duracool's web site and get further information from it.  There is a nine-page frequently-asked questions (FAQs) section, and the company owner, Barry Clark, is very helpful; he often is the one who answers the technical support line.

My only comment on sealant - and this applies to ANY sealant product - is that I would tend to avoid them if at all possible, preferring instead to put in the extra work to be sure that all joints and metal hardware are good, and renewed or properly repaired if necessary.  Sealants work by hanging up and congealing in areas of pressure differential.  Where the pressure differential is between the system and the ambient outside world, this is a good thing.  Where the differential occurs over components within a system, this is not so good.  Good sealants are engineered to be "selective" in this regard, but I do admit to a personal bias as a result of being a bit of a purist.

Fix that system properly, and then carry on!

Cheers ... EGK

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Ernest (Ernie) Kenward

Expertise

The challenges I most enjoy are thoughtful technical questions of a trouble-shooting nature in both electrical, power electronic and mechanical systems, mainly automotive but also machine control and small-machine PLC applications. Please note, however, that I am NOT a walking shop manual! I DO, however, make it a point to have those manuals and other service literature for those vehicles I DO own, and highly recommend that anyone serious about maintenance or modification of their vehicles do the same; MOST of your answers WILL be found there. For that matter, I do NOT go out of my way to acquire shop manuals for any vehicle I do NOT own! That being the case, any general query to me along the lines of "What is the meaning of this code read from the ECU of my 2015 XYZ?" or "Where is the fuse for the windshield washer pump found?" (try your car's electrical distribution panel for a start!) will not go far. What I do offer is a pretty good collection of literature, insights and hands-on experience with 1950s to 1980's Ford products (plus a developing database of information and practice with the Mercedes diesel cars), along with an engineering perspective and the ability to design and implement custom control, electrical and mechanical subsystems for vehicles. For that reason, I am happy to make my thoughts and efforts available to those who are of like mind and/or are seriously making a point of learning about their vehicles. Use the Opportunity to Learn!

Experience

A key skill in my work and hobby pursuits both is STRATEGIC TROUBLESHOOTING. I am a senior instructor in Electrical Engineering Technology at a leading Canadian polytechnic, my areas being Electrical Power and Industrial Control, electrical and electronics design and manufacturing, and AutoCAD and related CAD/CAE software - plus equipment problem-solving and new equipment design and prototyping. Hobby-wise, I have 30-plus years of experience in auto restoration, mostly in electrical and mechanical systems. Ongoing projects include a 1959 Edsel Corsair, my 1978 Ford E250 class-B motorhome conversion, and the care and upkeep of my Mercedes 300CD. My vehicles become engineering test beds for electrical and mechanical upgrades as ideas present themselves. This includes the design and production of circuit boards to restore or enhance features for which no OEM replacement parts are obtainable, or where better specifications or reliability can be had via newer concepts. Regarding the E250 RV conversion, I designed and continue to revise a custom power distribution system, managed by a Programmable Controller (PLC); this has made most revisions as easy as uploading new firmware as I develop it. The "mini" PLC is a powerful device for custom automotive control systems. One good example (there are many) would be the Moeller "Easy Relay"; these offer a wealth of control, monitoring and variable-and-status display options for such projects. A good example project which has worked well is that one for my RV noted above, which has been on the job - revised in firmware only - for a decade now. It is a load management and charging control system to avoid the sulfation-induced early failure that often befalls deep-cycle batteries used in RV power applications. The battery installed in 2003 lasted long enough to more tnan pay for the PLC that contributed to its longer life ... and the PLC will be there for the next battery as well!

Organizations
IEEE - senior member ... past WCC Student Activities; SME - senior member ... past chair, greater Vancouver chapter chair 318; Edsel Owners' Club - have served in various capacities on chapter executive during seventies; have been Power and Driveline resource on the Edsel Owners' Club "E-team" for more than a decade.

Education/Credentials
Graduate of UBC

Awards and Honors
Certificates of appreciation from IEEE and SME for work in student and chapter activities

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