XJ40 ( XJ81 ) 1986 - 1994

Weak A/C

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Old 06-04-2010, 04:06 PM
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Default Weak A/C

Yesterday, I had the A/C on my 1990 Jaguar XJ6 checked and serviced. The shop I went to is one that specializes in Jaguars, so they know their business. The system was leak-checked and filled with three cans of 134. By the way, this same shop replaced the compressor, dryer/dehydrator, and hoses just two years ago. Anyway, the mechanic told me that the system was putting out 65 degrees at the vents. When I take it out in this Tulsa heat, I might as well be driving with the windows down for all the good the A/C does. Does anyone have any thoughts on how to improved the A/C efficiency? I thought about putting some insulation on the hoses, but don't know how well that would work.
 
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Old 06-04-2010, 04:52 PM
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For improved A/C efficiency, you should use A/C on w/o switching on Manual Mode , use Middle Fan Speed and face level switch should be in middle or top .
Using MAX button is good for quicker cooling but it overrides full auto mode too .
I had my evaporator replaced as well as purge valve . I have been having no issues at all since then
 
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Old 06-04-2010, 04:57 PM
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check the gap between the condensor and the radiator. If this is full of dead flies, bug, small japanese cars it will restrict the air flow and affect the A/C. Do not attempt to clear it with a pressure washer as that will close the fins up and makes things worse. I know of two people that took their cars to A/C experts only to be told, after changing this, that and the other, that it must be the jaguar system that is to blame.

After I removed the condensor and clean it and the water radiator as well as removing all the crap from between them the A/C performed much better when re-filled
 
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Old 06-05-2010, 01:52 AM
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As above, plus,

Our '88 XJ40 had weak air, similar work done as per yours, about 10c at the vents waas the best we could get, then a suggestion regarding changing the the TX valve, no idea, so changed it for a 134a compatable valve, now got 4c at the vents, too bloody cold, but that can be lived with.

It was also noted that the system was "overcharged" with gas, which will cause isues I am told.
 
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Old 06-05-2010, 09:16 AM
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Good feedback. I'll try these and report back.

Thanks,

Robert
 
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Old 06-06-2010, 02:25 AM
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Subscribed, because I also have a similar ongoing issue.

Mind you I have not found the 'gap between the condensor and the radiator to be full of small Japanese Cars'!!
 
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Old 06-06-2010, 04:28 AM
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Richard, you dont travel in the right circles, or you drive toooooo slow, haha.

Ours are constantly contaminated with Korean cars down here, always get in the way on the interstate, and the mighty V12 has them for breakfast.

Last trip we sucked a small bird up the LH cold air intake, that was fun in the middle of nowhere.
 
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Old 06-06-2010, 11:23 AM
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Yeah I know, I need to get out more. LOL

Regards air-con I tend never to use it anyway. I grew up on old series Landrovers and rag top Spitfires. The biggest issue was spitting flies out, due to unfiltered dash vents.

I still struggle to figure out the reason for air-con on a modern soft top car.
 
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Old 06-06-2010, 11:26 AM
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Originally Posted by Translator
I still struggle to figure out the reason for air-con on a modern soft top car.

It comes in handy in very humid climates, places like Darwin,NT and Singapore
 
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Old 06-08-2010, 05:46 PM
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Well, my a/c was weak before. But now it has stopped coming from the center dash vents. It only comes from the vents at the windshield vents and the side vents. Any ideas on what the problem could be?
 
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Old 06-09-2010, 08:58 PM
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No worries. I was looking under the hood and found a vacuum hose that was disconnected. Hooked it back up and now it's fine.

Robert
 
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Old 06-10-2010, 07:08 AM
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Told ya it was simple coz Jags are simple cars to fix, ONCE you find the fault, and finding the fault is the fun part.

Enjoy
 
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Old 06-11-2010, 05:59 PM
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How true, how true. And tomorrow is Saturday. I get to play with my Jaguar as long as I wish.
 
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Old 06-12-2010, 06:00 AM
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I know what you mean, every day is Saturday, now I retired.

Another XJ-S V12 engine fire on its way to my shed, for rebuild, told him 4 months ago to do the hoses, yeh, yeh, yeh. Now I get to tell him "I told you so", and I am off on a short getaway with the "boss", so he is going to be happy, haha.

Now you have Jag knowledge, and confidence, you need to buy a V12, everyone needs at least 1 V12 in their lifetime, it stops you getting bored, seriously.

Enjoy, lifes way too short.
 
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