QuestionWhen the Jeep is first started, the A/C blows cold. After running the engine
for 10 minutes or so, it blows outside temp air. If, while still driving, I switch
to fan only for 10-15 minutes and then back to A/C, it blows cold again.
I had this problrm checked out by an out-of-state Jeep dealer this weekend (I
was travelling) and they suggested that they drain and re-charge the system
with dye added to look for leaks. That did not work (the A/C was still blowing
ambient air 10 minutes after strating the engine) and when I brought it back
in, they said it was the compressor. They did not have the part and sent me
on my way.
Now I am back home and w/o A/C. I felt like I got taken by the first Jeep
service center (why did they not check the compressor the first time? should
they have checked the freon levels first before recharging th system?) and I
do not want to be taken again for a compressor if that is not the problem.
My questions are:
1. Should I take the Jeep to a Jeep dealer or a shop that specializes in auto A/
C's?
2. What is a proper diagonostic test that will result in the problem being
repaired?
3. Wha do you think the problem is most likely to be?
I don't want to have every component "repaired" - just the one that is not
working.
Thank you.
Chris
AnswerHi Chris,
I think you should take it to a shop you trust. Since the dealer is intimate with Jeeps, my automatic response is to go there, but there are a few high-quality independents in any area. Listen to word-of-mouth, and do a little research in your area for quality repair shops. If visiting a dealer, you can usually judge their quality of service by something as simple as an oil change. At least with a dealer, you can go up the ladder if you are not satisfied; with an independent, you really have no recourse.
As for your repair, in my estimation, it was incomplete. Quite simply, the level of leak is considered gross if the system faults after 10 minutes. If the system was leak-tested (first!) with an electronic leak detector (audible-alarm type), that particular leak was probably large enough to be picked up immediately. Although dye inserted into the system is generally a good idea, it should be secondary to an electronic leak test. Sadly, that diagnostic (used to be standard in the industry) is roughly forgotten now, since the dye-black light method is easier to perform and often requires a second customer visit -- to the tech, it's a quick 1 hour labor charge without doing a lot of work. The best method is to charge, use the electronic leak detector first, and if that doesn't pick anything up, then insert the dye and run the system, inspecting it with a black light.
Now, I'm a bit suspect of a compressor problem, if only because, out of every A/C repair I've done on '99 GC's, the compressor accounts for less than 1%. You could go buy a black light yourself (some of the penlights are strong enough) and examine the system (preferably in the dimness of a garage, since black lights are not strongly illuminating) -- just shine the light on the various components, and follow the piping between them, concentrating on the couplings and attachments. The dye will show either a fluorescent green or yellow.
Keep in mind, this is assuming the system was empty when you visited the first shop, and that the vehicle has a gross leak. Out of all the problems I've seen with that particular model, the evaporator is a large majority -- and when they leak, it's sometimes difficult to find it, since it is housed in the HVAC case in the passenger compartment. As such, the part is relatively inexpensive, but the labor replacing it is often expensive (the Instrument Panel needs to be mostly removed, and HVAC case needs to come out). Outside of that, the Condenser (in front of the radiator) and the Service ports are more common than a compressor leaking. In terms of compressor repairs, they often self-destruct internally rather than leak -- unless the compressor manifold or combination hose (coupling to the compressor) is leaking, but then the repair is not a compressor replacement, just a set of O-rings or seal.
My advice would be to visit another shop, and see what their diagnostic turns up -- inform them that dye has already been installed, so the source of the leak should be readily apparent, and that you are a bit suspicious of the first diagnostic. Shops, and techs, are very competitive, and often challenge other shop's testing, so don't think they would protect each other. Then, if the diagnostic and repair is different, you can open communication with the first shop and work out some kind of reparation (rare, but not unheard of).
Good luck!
EDIT: I just re-read the vehicle -- I assumed it was a Grand Cherokee (WJ), and not a regular Cherokee (XJ). My answer remains the same, but less frequency with the evaporator, and more with the compressor, but only for internal issues. Still, the probability of a compressor leak goes up.
