So when I first picked up my 95 XJ12 the AC was working just fine. Then, briefly in the Chick Fil A Drive-Thru, one of the center vents started blowing hot. Then it went back to cold and operated as normal for about a week. Now, I have no cold air whatsoever. I've done a little bit of diagnosis and here's what I've come up with:

- Climate control had code #24 when I pulled them (I suspected this was triggered during the one warm vent incident). Cleared it and drove the car with the A/C switched on for a week. Still blowing warm though no codes are registering now.
- Condenser fans are not coming on when AC is on. They will only turn on after the car has been switched off.
- Condenser is quite loose. I suspect the bushings are bad as if I grab the hose to the condenser, there is a lot of play/knocking coming from the condenser.
- There is no evidence the Fan mod has been done, but unlike all the TSBs for 6 cylinder X300s, My X305 has only one AC Valve (I believe its a valve) as opposed to the 2 in all the TSB paperwork.

Since the car isn't throwing any codes for anything at the moment, where should I be looking next for diagnosis?

 

Is the compressor clutch engaging when you turn on the a/c?

Code 23 would come up if your refrigerant was low. And the compressor won't come on if it were really low. Code 24 is only a nuisance fault. if you have lost your refrigerant, the most likely cause would be leaking charge valves. Check by spraying them cap off with soapy water, watch for bubbles.

There is a relay at the right front of the engine compartment for the a/c clutch. The one nearest the engine in the row of 3 behind the right headlights.

You want to replace the bushings on the condenser. It is a likely suspect in loss of refrigerant due to metal on metal. Hopefully it is undamaged. New condensers for this car are not cheap or easy to find.

The electric fan mod does not apply to the XJ12. The fans will come on when the coolant gets hot enough. The big engine driven fan moves a lot of air.

You can get a new genuine Denso compressor with pulley for about $200. Denso part # 471-1349 for the XJ12. If so you want to get new valves, and a drier/filter bottle too. Thats the long tube behind the grill vanes. A shop will be able to install your new parts and do the evac and recharge for you. Its an easy job for someone that has the equipment and know-how.

I suspect the R-134 refrigerant will be outlawed in the USA within the next few years, so stock up now.

 

I'm honestly not sure if it's coming on, I haven't really checked. I do hear a "gurgling" noise from behind the dash when I do hit the AC button. How would I go about checking if the clutch is engaging?

I don't think there is any refrigerant loss as I'm not getting code 23. I just keep getting 0 so the system apparently thinks everything is okay...

Otherwise, I'll go ahead and check the relay, check the charge valves, and install new condenser bushings. Hopefully, the condenser itself isn't shot as the car was barely driven over the past 7 years...Are the condensers not shared with the 6 cylinder cars?

Thank you for all your help! It's been a big learning curve over the Volvos I usually work on!

 

Easy visual check since its right up top. Turn it on and take a look at the front of the a/c pulley. The whole pulley assembly should be turning. As opposed to when it is not engaged, only the outer pulley ring will be turning with the belt. Also the relay will click with the button push, which then engages the clutch.



I just installed this in March. I have the equipment to vacuum and recharge too.

The condenser is not the same as the six cylinder models. It is unique to the X305. About 4 years ago I had to find another condenser because mine was holed after running over a blown tire tread on the freeway at night. Destroyed the undertray and lost a brake duct but thankfully nothing else. I got really lucky to find one on Rock Auto that was on clearance, and was actually mis-identified for the XJ40. I saw a few aftermarket items in the UK and almost bought one before the lucky break.

So at least get some rubber pieces, like extra hose trimmings, under the condenser so it won't rattle around, until you can get the correct bushings. The radiator top brace has to come off (it holds the condenser too) but it is not too hard to put the bushings in. You won't have to disconnect the condenser, only lift it up a bit after the brace is off. Good time to replace the 4 radiator bushings too.

I know nothing about Volvos. But if I happen to acquire one, I know where to go for advice!

 

drier is mandatory while you’re in there

they’re what usually clogs the txv

 

Well, unfortunately, my AC condenser does have a hole in it. @SleekJag12 you said you explored some aftermarket options from the UK. Where might I find those?

 

Jaguar Classic Parts UK shows condenser MNA7390BA is "out of stock". I believe that to be a permanent condition. Their price was 620 GBP.

Jaguar Virginia Beach might have a new one for $1338. Yikes!

Jagbits has a used one for $650. Ouch.

I don't remember where else I saw them for sale in the UK, but I found a few with a web search. Aftermarkets, in the neighborhood of $400. Watch out for "parts houses" overseas that claim to have your part - they will take your money before they find out they don't have it and can't get it. Verify as much as possible.

Also keep in mind that condensers from other models of the era like XJS and XJ8 will not fit. Some sites claim they will.


This is the aftermarket one I got (Silla C0024). It is an accurate photo. It fit perfectly and appears to be well made. It has a different flow pattern than the original but was claimed to be more efficient too. I believe Silla went out of business a long time ago. I probably got the last new/old stock unit for sale anywhere!

I also stopped by an A/C service shop back then to ask if they could repair my old one and was told no. I don't think repairs would hold up to the extremes.

You might want to inquire at Jagbits. They are trusted. Good luck!

 

Thanks for the follow-up!

I called my local dealer and they wanted $1700 but then said it was NLA. I also contacted Jaguar Classic and they essentially told me I'm **** out of luck as they don't plan on reintroducing any A/C components due to manufacturing expense.

Thanks for the Jagbits lead, I'll keep that in my back pocket. First, though I'm gonna go pull a condenser for an XJ6 in the junkyard just to see if I can make it work with some custom lines. Heck, looking at how the X308 condenser's lines are set up, that might even work if there's a way to custom fabricate some mounts and make custom lines...

 

the 308 condenser basically hangs in the air, i’m sure you can zip tie mod it to your radiator

 

Thank you, great thought. How do I start diagnosis? I was not aware of that. I did not get an owners manual so I'm confident I need to get hold of one somehow

 

Which model and year are you referring to ?

V12 ?

See Page 110 , 78 and the 2 figures on page 80 show how the potentiometer works ( even though this is under the heater heading ) , and Z

www.jagrepair.com/images/Training Guides/703_SG.pdf \




See TSB for the codes\

14-10 (jagrepair.com)

You can drive the mixing door actuators with a 9 volt battery and listen for them to drive open and closed without having to dig into the heart of the dash

You can also drive a door to the desired position if the needed door position sensor is faulty and then clip the wire

The X300 has a trim adjustment knob on the center dash vents the X308 does not

A common fault the the fan driven cabin temp sensor below the steering column that gets clogged with dist and lent

 

Question @SleekJag12

When you bought your new Denso compressor, did it only have one one low port on the plate where usually the 2 lines connect? I just ordered one from RockAuto based on some of your previous posts, and the attachment points on the new one are markedly different than whats on the car ATM

 

Duh, I see the photo fromm before....

Follow up question, did you just change out the plate?

 

There is a do it your self compressor overhaul kit Avail

See the 2 interesting instruction videos

The question is if your compressor is the same Denso 10PA series unit on the inline 6 X300

There are alot of parts avail on their website:

Featured Products (shopcenturyautoair.com)



and

 

Right Swagger, use your original pipe fitting plate. Easy to do, 4 bolts. Some new compressors come with the pipe plate, not this one. It did come with a new plate gasket. Very little oil came out of the old compressor, but I added about 2 oz of the new oil to the new one using spitball logic, and I feel good about it.

At that price I couldn't see fiddling around with a rebuild project, but thanks Parker! And yes the compressor unit core is the same 10PA as in the six, with a different pulley, different pipes and electric hookups.

 

Interesting Update:

I pulled my condenser and brought it to a shop that specialized in AC condensers on Semi-Trucks. They performed a leak test and apparently, it passed with flying colors! So that's good. However, if there was no leak and my compressor clutch was kicking on and off as it should, what else could be causing the system to blow warm?

 

Was there any codes on the test with the front control panel ?

There is a common fault with the cabin temp sensor below and to the left of the steering column getting clogged with dust and can be cleaned , this is one of the things that does not show up as a fault code but it mixes hot and cold air

Turn the knob on the center vent from blue to red and you may or may not hear the specific door motor run , you may have to give it some time

This is the red circle on post # 11

The variable resistor control knob can go bad and the motor it drives be good

There can also be a bad connection with the outside air temp sensor located in the left front wheel brake cooing duct located below your left fog light

This is a thermistor and it reads on a meter opposite of how a thermocouple would read

 

There was a #24 code, but I cleared it and drove for a week and the system continued showing no faults despite blowing warm. Compressor kicked on normally, etc.

 

Code 24 is titled Face Vent Demand Potentiometer which is the red /. blue dot control on your center vent

It may not have registered as a fault coda later on as computers are not perfect

There should be a way to remove the center vent

Ding

 

Interesting. I definitely fiddled with that knob before the system went warm. I also found plenty of dust in that sensor beneath the steering column...

Well, I'm going to pick up my pressure-tested condenser tomorrow and I purchased all the tools to charge the system myself. I'll report back with the results later!