Looking for a little advice here as I've researched quite a bit but can not find the AC being replace on my type 02 4.0 s type. I've found the parts easily enough but looking for more instructional help. I have a shop that will pull the freon out and will vacuum and charge the system for 125.00.
No cold air blowing any longer
The low side pressure is high and high side is low, compressor turns on but has evidence of a leak with some green die. All fuses are good.
I've done power steering work, water pumps, coolant systems and feel that I can replace the compressor, expansion valve, drier, condensor if the system is depressurized. I've seen the how to here but I think it was on the v6. I read somewhere where some motor mounts might need to be removed and jack the motor up slightly to pull the compressor but the post wasn't specific on the exact model. What should I look out for or what are the secret how to's
Thanks

Before you tear in too deep and start changing everything in sight, you may want to run through some quick tests here, specifically in posts #2, 4, and 5:

https://www.jaguarforums.com/forum/s...ol-how-185002/


You may very well have more than one fault in play. For example, if the DCCV is stuck open, that will dump heat into the cabin and mimic a failed AC system. You mentioned the AC pressures were out of whack, but you may still be getting some cooling although it's being overwhelmed by heat from a bad DCCV. Test the DCCV first, per post #2 at the link above, and then go to either post #4 (some cooling) or post #5 (no cooling). For example, you could have a bad relay letting the compressor clutch slip.

The potential leak? Your call, but if minor, I'd be tempted to refill the system and see exactly how bad the leak really is. If it holds well enough for the system to operate adequately for several years, I'd pat myself on the back for the money saved and just periodically service the refrigerant.

I am betting on a faulty compressor based upon your description. The factory units are known to fail (my 2005 S-Type's compressor failed in 2010, less than a year after the factory warranty expired). Put the car up on ramps or jack stands, remove the belly pan, and have a good look and feel of the underside of the compressor. If you notice a greenish-colored, slightly greasy slime coating the underside of the compressor, it has indeed failed. I did my research and chose to install an aftermarket compressor built by Omega in June 2010, and it has performed like a champ ever since....

Thanks for quick replies. I'll read the suggested threads.
I was doing oil change and general checking underneath and saw the oily green coating on the compressor and the area. A few weeks later the air was just not cold. I can adjust the dual temp buttons to make the air warmer on 1 side so I was thinking that valve is working. The temp here in ga just started to get warm enough for some ac.
the compressor is turning and doesn't really stop. I'll check the electronic fan to see if it will turn on.

can any one verify that the expansion valve is inside the dash and is there a method of checking it to see if its working?

This would seem to indicate a duff compressor.

I believe the expansion valve is in the dash and hard to access.

It's item 3 here:



I think the 4.2 needs the engine lifted JTIS doesn't mention this in the 2000 info.

Please post an intro in the new members section when you can, thanks.

It is directly behind the engine, center of the firewall, half in the engine compartment, half in the dash. I've no experience with one, but supposedly it's a bear to change. However, based on reports here, it is rarely the problem for low cooling.

Lately I've been taking ginkoba supplements, giving me the incredible ability to read minds. For example, I've deduced my wife wants me to help out more around the house and not grumble so much when forced to do Mandatory Family Fun time with relatives. Uncanny, huh?


I'm also picking up a strong vibe that you're just itching to change some expensive parts to get your AC back. I can't caution you strongly enough to really investigate the situation first. Even if you THINK the DCCV is fine, run one of those simple tests I gave to be sure. Is your compressor worn out? Maybe, but spending a few minutes to check the compressor clutch for slippage could save you a lot of time and money. That troubleshooting guide I put together isn't just a bunch of mumbo-jumbo for other people. It was intended for situations exactly like yours.

That $120 your shop wants to charge you? I'd rather spring for a basic AC service set (gauges and vacuum pump) and learn how to do it myself.

Based on my experience, the expansion valve rarely fails due to its simple design. Replacing the expansion valve requires removal of the entire dash, heater box assembly to access the evaporator. The engine inlet manifold must also be removed on the 4.0 litre engine. As others have suggested, it's more likely the compressor that needs to be replaced.

Before opening any of the hoses/connections, you must have the refrigerant discharged by a competent air conditioning shop as it is illegal in many jurisdictions to discharge the refrigerant directly into the atmosphere.

Be sure to correctly measure the amount of compressor oil added to the new compressor before installation. You must also replace the drier as failed compressors often release metal particles into the system that can clog the condenser and evaporator.

Did the the test of the system with temp probes and dccv seams ok. There's no condensation building up and dripping from the car and the compressor seams to rarely cut off. With low side reading high and the high side reading low is it possible the freon is low because of a leak at the compressor. I hear a hissing sound when the ac button is turned on so I'm thinking I'm hearing the freon pass thru the expansion valve and changing to a gas or back to liquid? The air temp hasn't been to high and using my obd2 reader the coolant temp barley reaches 200. I see the fan turning after test driving but not before when letting the car sit to warm up. What temp does the fan kick on?

Pressure readings would indicate a flow restriction or compressor that has disintegrated internally.

Take it to a Auto shop specializing in AC Services.

I don't believe that that part is a apart of the ac system. You must be lost.

After re-reading this post I stand by my original comment. Sorry but your chasing shadows here. Let me lend my $0.02

As a previous owner of a 00 S Type 4.0 (feel free to check all my posts over the years) I'll tell you the expansion valve is rarely faulty as others have already pointed out.

Take it to a shop and let them sort out the issue(s) for you.

Based on your original post: low side high and high side low pressures and compressor continuously running - sounds like the system is over charged. (But I guess I'm still "lost") moving on...

Hey, 2000jag.....your location says GA; if it's in the Atlanta area, take it to Kuhn's (Northlake Cadillac-Jaguar) in Tucker.

​​​​still lost are we?

at least your second 2 cents had a diagnoses.

Thanks for your input though.

It's possible that ship has sailed.

Please refrain from the personal comments they won't be tolerated here.

Clearly I'm done attempting contributing to this post Norri...

Popcorn anybody?





I'm still leaning towards a slipping compressor clutch...

Easy enough to test as detailed at my HVAC troubleshooting guide.