Hello

I am a proud owner of a XK 2010 5.0 in Indigo Blue. Just bought the car last week with a full dealer service history with only 53k miles on the clock, only downside was that the whole car has been repainted.

After fixing some minor wear and tear issues, i am down to two issues that I need advice on:

1. AC blows hot after cold start or a lengthy stop - i emptied the system and recharged to 48 psi with fresh refridgerant to no avail - AC blows ice cold when car is on the road but hot when the car comes to a stop. Took it to four 'specialists' - one said its a fan sensor issue, the three others told me that if it were a fan issue the car would overheat (which it does not at all) - it needs a new compressor (very expensive repair ) ??

2. Rough Idle at low RPM - car idles quite rough when AC is not turned on and idling at a low RPM. Dumped two Liqui Moly injector cleaners in the fuel tank and drove it at high speeds to no avail. I know that it is a DI engine but at least that would clean the injectors? Any ideas? I am surprised at the rough idle since the car only has 53k miles on it even though it is 11 years old.

I would appreciate any assistance on these two issues.

Thanks

 

Hhmm, mine does a bit of the same. When hot outside, A/C is perfect. When maybe 10C outside, the first 5 minutes it blows too hot air for my taste, then settels and works fine. I doubt it has to do with A/C cooling not working, so don't spend $$$. Since I use it mostly in nice weather, I livewith it...

 

First, welcome to the forum. Second, please comply with the New member requests. It provides info to everyone so we don't ask dumb questions when asking for help. New paint huh? Have you removed the forward top/bottom plastic cover(s) and checked for over-spray or other stuff around the rads.?
When you emptied and refilled the A/C did you perform a vacuum check...to ensure system integrity?
Is the car showing any codes when scanned with a OBD2 scanner? rough idle at low RPM can be caused by ....fuel problems...ignition miss fires...intake air problems....gummed up valves etc. By the way, there is no real time engine temp gauge per say. To get real time engine temps, you have to monitor the ECU with a live data scanner through the ODB2 connection.

 

Welcome to the forums Sager Alanizi,

1. AC blows hot after cold start or a lengthy stop
You are getting ICE COLD air so that suggests to me that the AC is correctly charged and operating.

You are not getting COLD air when the vehicle is brought to a halt. That suggests either distribution (servo motor controlled flaps in the heater unit) or a sensor fault. The ATC (Air temperature Control) module takes signals from a number of temperature sensors and one or more of these could either have failed or be giving a false reading.

Jaguar SDD (Symptom Driven Diagnostics) is likely to provide some useful information on possible causes. The alternative is swapping out sensors and that could soon get expensive.

2. Rough Idle at low RPM
Rough as in a misfire or surging and falling RPM?

Again, my first action with a powertrain fault is to run a diagnostics session. You'll need a laptop more often than you'll need a wrench with these vehicles.

Graham

 

I assume you and the specialists all checked the belt while idling the car at a rest to be certain that it isn't fighting the engine, and also not turning the compressor properly, causing both problems at the same time. What about removing the belt and turning the compressor by hand with the engine off to check it turns okay? Depends how much you want to DIY but if you're sure they're right and it needs a new compressor then you have complete freedom to remove the refrigerant again, pull it off the engine, and take it apart.

 

My AC did the same thing, worked fine under load but would completely shut down and blow hot air then start back up. AC in cars stays on at all times, even at idle you shouldn't see a dip in temp unless you drive a 3 or 4 cylinder car. Back in the day with my older toyota that was how it worked, my AC button was also like a turbo boost when I shut if off for more power.

Anyway, I was under warranty and the dealer replaced my compressor no charge, however it was the pressure switch. It is a known problem, here is the technical bulletin regarding this issue. Also there have been several threads over the years about this topic, one notated below:

A/C blowing cold only above 2000rpms - Jaguar Forums - Jaguar Enthusiasts Forum

 

Hello All,

Many thanks for the informative responses,

I should have clarified more that the rough idling is a surge/fall action not a misfire. I am also not convinced that the car needs a new compressor however me not being so tech savvy I thought of getting help here.

It seems that it would be best to get the ECU OBD scanned prior to carpet bombing and start replacing spark plugs, sensors etc. for both issues the rough idle and the hot AC.

On a side-note, is there a fuel filter than can be changed on the 5.0? I would like to replace that on an 11 year old car...

cheers

 

Tampa, found your attachment very interesting..because it said "compressor clutch if applicable" I thought all A/C compressors have a clutch.
without one there would be parasitic drag on the engine. When the A/C system is not in use. Admitting I am not an A/C expert, but I will have to work at separating the wheat from the chaff, when it comes to TSB's.

 

Seems there are some clutchless systems out there, not sure if Jag uses them in any vehicle. You kinda focused on the irrelevant part but I get it, if they have misspellings or misstatements they must be too stupid to have the rest of it correct! LOL I jest my man.

Electronically-Controlled-Clutchless-or-Variable-Drive-Compressors.pdf (cancore.net)

 

Sager, I applaud your mindset, This forum is a treasure chest filled with diverse knowledge, experience and possible resources.
We all want to help each other to learn and enjoy our cars. It gets testy at times, Such is the human condition. Darn it I want to see some pictures
of your Jag.

 

Hello Night,

I am used to cars like the Nissan Patrol and Toyota Land Cruiser which are mostly mechanical, unlike the Jag, with which I will need every bit of help I can to keep this baby running smooth ...

Here she is after a polish and getting tinted. As I mentioned the only real issue with the car was the repaint job, which was done in the same original color just a respray as the car had been left sitting in the scorching sun and the original paint had faded. No accident damage though

 

Tampa, thxs for the second attachment..I downloaded it and will probably take me a week to digest it.
I feel sorry for all the customers that go to garages with less than capable techs ( me being one) .
I like that the "clutch less system" allows for deeper T/S , but it still is a clutch, sort of speak ,however it is controlled.
I am not a technology hater, but I want technology to be helpful and purposeful.

 

Sager, Thanks for the pic...Blue on caramel...got to love it.
Hope your not going to flip it. Unless you want a Nissan GTR. LOL

 

Each to his own, I'd run away from a caramel interior (fine of you have a laundry problem I guess?), although did want kyanite blue but sadly not available in a Dynamic R

 

That was my 2nd color combo and just missed one in Las Vegas when I was looking. Finely found my Red. Good show and enjoy

 

My first choice would have been British Racing Green and second Kyanite Blue. As for interior definitely grey on white with black piano trim. Alas beggars cant be choosers....

 

The 2010 does not have a traditional, "swap-it-out" fuel filter so you can cross that off the list.

 

Interesting, i actually found a fuel filter on amazon that they describe as fitting. Of course I would trust your word. In case the fuel system is dirty that means I would have to remove the fuel pump?

 

Regarding the rough idle: That surge/fall hunting at idle can be a dirty throttle body valve. A cleanup around the the intake butterfly valve in the throttle body often resolves the problem. Hope this helps.

 

I just wanted to attempt a throttle body clean at home and got unnerved. Not that I have never done it before, its that ive never worked on a Jag before with so much sensors and a tight engine bay.

Any suggestions or tips on cleaning the throttle body and MAF? Stuff that I should avoid or look out for?

Thanks