So my 1996 American LHD xj6 has a great A\C when it works. It always works but sometimes I don't hear the hissing sound of the compressor and the air begins to get warm. When I hear the hissing sound and the compressor the air gets really cold and it works great! Is this an issue of low a\c gas or a compressor that is about to go? Its been like this for over a year and most times doesn't give me an issue. thanks guys!

 

have you tried having it pressure tested for leaks and regas

 

No I haven't had it checked however if it leaked wouldn't the fluid be gone by now?

 

If the refrigerant pressure is too low, a cutoff switch will not allow the compressor to run. The pressure will change as a result of ambient temperature. Maybe thats what is happening.

 

Mine began doing the same thing. Went to a specialist who said I have a bad expansion valve. He said it didnt need any gas but still right after leaving the place the ac was super cool and nice but a few weeks and its back to poor cooling and basically only cools well when engine is not revved...

 

avioni:
Obviously, the new valve may have craped out, but there is also the possibility your compressor is shedding some contaminating metal. You can get an inline filter for the AC to catch such stuff, usually used after a compressor explodes internally - you cant flushh all of the metal out.

 

Can you explain the flush out procedure? And if it is low on gas, would the canisters sold at auto parts stores suffice or do they cause damage to the system?

 

The receiver / dryer canisters are full of desecant to remove water/AFAIK. none also filter the lines. There are aftermarket filter like this:
ACKITS.com Automotive Air Conditioning Parts & Equipment.: 13128TSI - Universal In-Line Filter
to use after a compressor "explodes" into the lines.
The one I referenced is just an example- you need to find one to match the system you are working on.

And, I assume the canister you refer to are th ones that have r-134 refrigerant in them. If you need refrigerant, thats the stuff. But it is a terrible idea to just add reffigerant without knowing you need it, since too much can do bad things to the compressor. Read up, or take a course, then get a set of guages after you know how to use them. Or just cross your fingers and add R-134 and risk it!

 

Ross is that a typo ("none")? The receiver/dryer also acts as a filter. It is the first component after the compressor, but I could see that a big time failure of the compressor would probably blow debris past it.

Its a good idea to replace the receiver/dryer whenever the system is opened. It is not an expensive item and will keep the refrigerant clean and dry, as required for good cooling!

Avi, the shop replaced the expansion valve? What about the receiver/dryer? It could be clogged after 17 years. It is the long tube in front of the radiator & condenser, mounted horizontally at the top.

I think we need a sticky about air conditioning service. There are many questions about recharging, and my concern is with the dangers of the system which many don't seem to realize. Also, more harm than good may come as a result of improper servicing, more so with the a/c than most other systems. Maybe I can write one up....... it would be lengthy.

 

Richard:
No, I believed that the receiver dryer did not also have a filter. But you say it does. I must say it has been years since I sawed one apart, but it did not seen to have anything but a bag of desicant then!
Thanks for straightening me out.
And yes, considering how many folks are inclined to just download a can or two of refrigerant without actually testing the system, a sticky would help a lot!

 

I couldn't agree with you guys more! that's why I didn't want to just put the refrigerant in without knowing what the real issue is because the a\c works great every time, its just those rarities that im at a traffic light and it gets warm suddenly. None the less, I will try checking the upper line but a sticky would be helpful!

 

If your in traffic and it gets warm check that your electric fan is working...the condersor has to get rid of the extracted heat. My daughters Mariner started blowing warm the other day in traffic and sure enough the fan relay was not allowing the secondary fan to come on....the low side was up to 100+ psi so I rinsed the condensor down with water while it was running and viola she started cooling and dropped the low side to 40 psi, changed the fan relay and problem solved. A/C is NOT a magical black box it is a simple sytem of converting a liquid readily to a gas and rapidly expanding that gas to cool, similar to opening a bottle of cola out of a cooler full of water and ice, the top part freezes as the gas expands and is released. Don't just "add" R-134, buy a simple, single, low side gauge and duct temp thermostat at the local auto store and read a few a/c FAQ's/tutorials on line with respect to expected low side pressure vs OAT vs expected duct temp vs OAT ( outside air temp)

 

Good advice, JT.

One bit of advice applies to any hookup of charging/gauge sets: Be sure to purge the hoses of the charging/gauge set, otherwise air and moisture will be sucked into the system immediately upon engagement of the compressor, via the low side port. Usually this can be done by loosening the hose fittings and allowing some gas to escape from the hoses, before starting it up.

Also, wear good gloves and eye protection. Don't burn yourself from the hot system components or the super cold refrigerant!

To clarify my definition of the receiver/dryer... it is probably not meant to be a filter, although we could say that it has a filtering effect because of the dessicant material! If the dessicant is saturated with moisture it would restrict the flow too.

JT, what a perfectly tight front end on your XJS. You can be proud of that! And I mentioned those two V12 logos exactly, in my last post in the X305 section about Fritz's new XJ12, immediately before I came to this thread! Wow!

 

When I got my 95 XJ6 the AC was not working & I had a low refrigerant (23) code on the climate control (see section 14.11 of the XJ6-XJ12 service manual) & the compressor was jammed. I did a lot of research & bought a vacuum pump & AC gauges. I ended up replacing the seals throughout, the compressor, the dryer & flushing the lines. I did not change the expansion valve because I found the pressure side hose from the old compressor to be clean of debris. (changing the expansion valve is a big job) I've attached a link to an A/C training manual that I found to be very informative. I believe that anyone troubleshooting their A/C system would do well to refer to this manual.

http://www.ariazone.com/manuals/Auto...g%20Manual.pdf

I just made a 600 mile weekend trip to New England (USA) in 90+ deg F (32deg. C) heat & everyone was cool calm & collected!

 

Thanks for all the info guys-Got an update-The A\c begins to fade out to a certain extent when the car is not in motion. Any idea what that means?

 

Could be as said above, the cooling fans behind the radiator may not be running

 

So where is the fan relay?

 

Ok so the fans come on eventually and the car after sitting for a bit does begin to cool the ac quite well but it takes a bit. COuld this be because it is low on gas?

 

As stated before, go to the auto parts store, buy a simple A/C check gauge and find out if it is low before you add any. Here's an example of one. I have a full gauge/manifold set BUT I also have one of these "quick" check gauges which helps determine quickly if you could use a little r134. You can also add r134 with this too. The answer to your question is "yes" it could be low but you want to be sure before you add any. My XJS started blowing a little warm the other day (it's been 5 years since I retrofitted to R134 w/o having to service it) and it was only down about 8 oz and once topped up it's back to blowing ice cold air in the FL heat.

FJC R134a Recharge Hose with Gauge #6036

 

If you imagine, the amount of air being forced over the condenser at speed will be far greater than when the car is stood with fans running. Therefore the cooling effect over the condenser will be greater, hence the A/c will be cooler.

If the car is getting cool whilst stood and the fans are running then it could need re-gassing. If you have a pollen filter, then check that also.

Hope this helps.