Folks,

Well it's warm again, at least in Louisiana, and the AC in my wife's S-Type (3.0) is not cooling as good as it did last year. At idle the performance is poor, and it slowly gets better with speed. At 35 mph it works okay, and at 45 mph and above it works good. The pressures seem good (at ambient of 86°F and at 1,900 rpm with a fan feeding air to the front grill, the low side: 45-50 psi and high side: 240 psi. The condenser is clean and free of debris.
The radiator fan comes on when the A/C is turned on, yet it seems to be running slowly. Later, after 30 minutes of idling with the AC on, the radiator fan seemed to be running faster (audibly louder). Does this car have a variable speed fan? and should it be running faster at all times with the AC on?

Baffled and warm,
Charlie

 

Did you check to see if any of the hoses are icing up? That is a good indication of low freon/refrigerant. Other options are blockage in a liquid system.

 

Did your car cool well at idle before?
There is TSB about poor cooling at idle. Basically there is spring loaded valve on the A/C compressor that needs position swapped with the spring. Then reassembled and recharged to address good refrigerant flow at idle speed.

 

Here it is..........

 

Mine's doing the same thing. But frankly, that's way on down my list of things to do. (After getting the car moving under its own power, and stopping the power steering reservoir from hemorrhaging all over the garage floor!)


Is it going to damage the compression or AC system to drive the car when this TSB work hasn't been done?

 

No it won't the mod just increases the efficiency at low engine speeds.

 

My wife can't recall if the AC worked well at idle/slow speed last year or not. I have to go to work for a week, when I get back I will follow the TSB regarding swapping the spring & valve.
I did notice something that seemed strange to me, when I added a little refrigerant, at idle the low side was 65 psi & high side was 150 psi and as I added some gas the pressures did not budge. The did jump up, "to a normal range", when I increased the rpm to 1,900-2,000. Maybe this is a result of the valve restricting flow at slow speeds.

 

Look at the electrical earth points, my x type had this problem, got my tester out and after about half an hour or so, located the problem to a bad earth.

 

When looking at the plate and spring see if the bottom of the compressor is greenish-yellow stained or not. With your miles it's very common to have the compressor leaking at the body.

No point in replacing the valve or spring if you see stains. Lucky for us the compressors/dryers are pretty fairly priced since the Lincoln LS uses the same one.

That 240 psi on the high side looks too high to me.

Be careful about topping it up. At this point you really don't know what the refrigerant level is.
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Good advice on checking for greenish-colored compressor oil stains at the bottom of your compressor. The factory compressors are known to slowly die. My 2005 S-Type's compressor slowly bit the bullet in May/June 2010. An aftermarket Omega compressor replaced it and has done quite well ever since....

While you're underneath the car looking at your compressor, be sure to locate and insulate the aluminum A/C line that tends to drop down and sit directly on the top of the steering rack case. Road vibration gradually wears a pinhole in the aluminum A/C line at that exact spot and you lose all your R134a as a result. That aluminum A/C line is a dealer-only part that sells for nearly $200 and it is a bitch to replace, especially if you have monster hands like me. The solution is to cut a 4-inch section of rubber hose that has an inside diameter of about a half-inch, slit it lengthwise, wrap it around the aluminum A/C line at precisely the spot that tends to sit on top of the steering rack, then wrap it firmly with electrical tape. Your aluminum A/C line is now properly protected from wear-and-tear and you will now avoid this future problem. Every 3.0 owner should do this job immediately. It took me and my A/C shop nearly a month to figure out the problem....

 

Thanks for the tips. Iwill check the bottom of the compressor for staining and add a rubber hose to the aluminum line as well (I don't have small hands either-.

 

On three different vehicles (including my '02 S-Type), I have had poor AC performance at idle that was caused by a slipping compressor clutch. In all cases, the duct temp seemed okay at higher RPM and vehicle speeds.

One one vehicle, the slippage was due to a worn clutch. The manual gave a spec for an air gap with the clutch deenergized, and it was way out of limits. A new clutch assembly took care of that one.

One another vehicle, the issue was a poor ground at the clutch coil. The clutch engaged, but didn't clamp sufficiently. I found the problem with a voltage drop test. Repaired the wiring, and performance returned to normal.

On my Jag, the relay controlling the clutch coil had been arcing and building up a high internal resistance between the contacts. Until the relay totally failed, the clutch had been engaging but not clamping sufficiently. A new relay fixed the problem.

I'm not saying this is the only possibility, but it does fit the symptoms and may be worth investigating. A quick and dirty troubleshooting trick is to put paint marks aligning the clutch plate and the pulley. Now jumper 12 volts from the battery directly to the clutch coil. Start the engine and run at idle for about 15 seconds or so. Don't run any longer than that, as the compressor clutch won't be able to shut itself off if commanded by the pressure switch. With the engine off but the coil still energized, look at the paint marks you just made. If the clutch is doing its job, the marks will still be aligned. They might shift a tiny bit at initial start-up, but I'd say anything more than 1/4" indicates a slipping clutch. If so, then you have to determine if you have an electrical issue not providing full power to the coil, or a mechanical issue such as a worn clutch assembly.

 

Hello Everyone.

I am here looking for help since it is becoming very hot and humid in Va. My A/C is only blowing hot air. I took it to the shop and had it charged but it did not even get a little cold even during the process. I thought that driving for a while with the A/C running would make a difference; IT DOESN'T. I am basicly being told by the mechanic that there are a lot of different things that can be wrong and to change out each part until "WE" get it right...Really. There has to be a better way. I did have my DCCV changed last winter because the heat was not working and that corrected the heater problem. The A/C even worked last summer, after having it charged. It just did not work this time. The following has been inspected by visual inspection only:

1. the compressor is turning
2. the freon levels are correct
3. the coolant is at proper level
4. the fan is turning, but not very fast(not sure if speed should change with a/c on)
5. the inside control work(clicking over from heat to air and vice versa)
6. checked both filters and they are clear
7. check the fuses indicated in my book (seem to be fine) ALTHOUGH I HAVE ALOT OF EMPTY SPACES IN MY FUSE BOX UNDER THE HOOD, SHOULD THAT BE? THAT'S ANOTHER FORUM I GUESS.

CAN and WILL anyone here PLEASE HELP me with this issue.
DON'T WANNA BE ROBBED BY THESE MECHANICS!!!!
THANKS IN ADVANCE FOR YOUR HELP!

 

Yes, there definitely is a better way. Run, don't walk, to a better mechanic. I'd suggest an AC specialist. Such a specialist could properly diagnose the situation and make repairs without draining your wallet playing parts roulette.

A few things to consider, and an AC specialist would already know these things:

Check if the evaporator is actually getting cool. Could be it is, meaning all the underhood stuff (compressor, condenser, pressure transducer, etc.) is working fine. In that case, you could have a heater valve dumping hot air into the outlets for whatever reason, either due to a stuck valve or a wrong command to the valve. Try testing the AC outlet temp while the engine is still cold. For the first few minutes, until the engine coolant warms up, there would be no heat source to warm the AC ducts, even if the heater valve was open.

If the evaporator isn't getting cold, then concentrate on the "refrigerant" side of the equation. Make sure the compressor clutch isn't slipping, as I previously described. (You can remove the compressor control relay and jumper across the terminals for direct battery power to the clutch. Remember, only run the engine briefly like this for troubleshooting.)

A good AC specialist should be able to externally check the lines for internal blockage. A partial blockage will create a cold spot on the downstream side. A specialist should also have an ultrasonic listening device. If there's a blockage, this device can pick up the change in sound of the refrigerant in motion, even though we can't hear it with our ears.

I wouldn't worry about the electric fan just yet. Even if failed, you'd only lose cooling at low speeds. At higher vehicle speeds, there should be enough ram air through the condenser for adequate cooling.

Hopefully that should be enough to get you down the right path. Concentrate first on determining if the evaporator is getting cold. That would tell you which direction to go after that.

Don't get discouraged, thinking this system is too complicated and that no shop can fix it. The AC system uses a lot of FoMoCo parts and design logic. This should be a piece of cake to a good AC specialist.

 

When I had my S-Type it did the same thing when temps got over 90 degrees. My hack solution was to put the transmission in neutral and rev the engine to 1500 rpm.

 

What flavor S-Type do you have? If it is the 3-litre V6, be aware that the aluminum A/C lines that sit just above the power steering rack can drop down as the years go by and sit directly on the steering rack. Road vibration eventually wears a pinhole in the aluminum A/C line and your system will hold a charge for maybe 24 to 48 hours but then reverts back to blowing warm air....

This is a design flaw. When it happens, you must replace the aluminum A/C line and protect it from rubbing on the steering rack again. I wrapped my new line with a 4-inch section of rubber hose at the spot just above the steering rack. If it settles back down on the rack now, the rubber hose will protect it....

This issue took some careful investigation to uncover. Putting the car in the air on a lift was what allowed us to find the problem. We couldn't see the pinhole, but we could sure see the chunk worn out of the aluminum line by what was probably years of road vibration while it sat on top of the steering rack....

All 3.0 V6 owners should check their lines immediately. Get a 4-inch section of rubber hose, split it, wrap it around your lower line just above the steering rack, wrap the rubber hose with electrical tape, and finish off with a couple of worm-drive clamps (not too tight) to secure it permanently in place. Problem solved....

 

Folks,
Well "carelm", I did a similar thing to help diagnose the problem. I took a drive in traffic and every time I came to a light I put the transmission in neutral and revved the engine to 1,800-2,000 rpm, whalah! The air was definitely cooler idling at 2,000 instead of 600 rpm. I reversed the valve and spring per the TSB on this problem...boy was that a lot harder than it sounds! I intended to remove the compressor to allow more access to the plate, bolts, valve, and spring, yet as I tried removing the top forward mounting bolt (on the compressor) the head of the bolt started rounding off instead of loosening. I was using a proper 13 mm box-end wrench in good condition, the bolt must have been over-torqued from the factory. Well I removed the plate and swapped the spring and valve with the compressor in place. With my big hands that was a real chore. I alternated between praying, increasing my vocabulary, and dreaming of the Ford Taurus (more room in the engine compartment) my wife had previous to the Jag.

Jon89, I did see the tight clearance on the aluminum AC line to the steering rack. The line, on our car, looked okay and I added a 4" piece of heater hose to it for insurance and preventive care.
Thanks guys for the help and steering me to the TSB regarding the valve and spring. It cools much better now at slow speed.

 

OK. I am back. I want to say thanks to everyone that replied. So I took your advise kr98664, and took to someone who is declared to be an A/C specialist. He says that there is a leak in the hoses that connect directly to the compressor. So, now I am searching for the hose that I need. Is the picture below the part that I am in need of?


Does anyone know what number in the diagram is the part I am seeking? I do know that is definitely NOT #7.

Thank you

 

It would be item 3 if the leak is in the hoses connected to the compressor.


But make sure that hose is the one he meant! We don't see many A/C leaks. Usually something else.


Maybe replace the O-rings on the compressor plate?
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Thank you to everyone that gave me great advice. Here is what has been done up to date:

Specs: 2000 jaguar s-type 3.0 v6

1. The ac system has been evacuated and refilled.

2. The ac hose that did have the leak connecting to the compressor has been changed.


How this is what is going on now:

There is still no air!
The coolant lines to are hot! Which leads me to believe that the dccv (dual climate control valve) is the culprit. In the past, during the winter, the valve had to be changed because it was stuck in the "AC position" and so the heat did not work. After changing it, the heat worked fine. These days, the heat is still blowing like a champ, even when the AC is suppose to be on. The symptoms seem to be the same now, just the opposite of what I want.

I have a DCCV on hand and I think I am gonna have it changed just so that I can rule it out. Hopefully, it if correct the issue and I can get some AC in my car and my life!
Does anyone here have any experience with this and if so, your input would be greatly appreciated.

Thanks everyone!