Two years the air conditioner was not working. Recharged the system with freon (had the dye). Worked all summer then spring the following year, no cold air again.
I thought I seen slight red color a the pump so I changed the pump and the dryer. Vacuum the system and recharged, work fine all year. This spring no cold air again.
I added one can of freon and no change, pipes coming out of the compressor are hot. I thought I read an article that if both pipes coming of the compressor are hot that is a good indication the compressor is bad. Can someone verify this? Is there some thing else I should look at?

 

Sounds like you had a leak in the past. It may still be active but I can't tell from here.

I'm not familiar with troubleshooting by pipe temperature. Keep in mind our cars have a self-regulating compressor, unlike most vehicles. If you find some stuff online, it may not be applicable for our cars.

Have you seen our troubleshooting guide?:

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


It was written specifically for our cars and is based on symptoms. Work through the applicable steps and hopefully you'll resolve the problem.

 

No I haven't seem this. Thanks I will take a look.

 

After going through the trouble shooting guide (TSG) I decided to change the DCCV. In the mean time I had a small accident that damaged the condenser. So I changed the DCCV, checked the fuse, installed a new condensor, vacuumed the system and added 3 cans of freon. Still no cold air. Checked DCV per TSG using infrared, radiator hose 200F, hoses out of DCCV 125 & 135. I thought they would be cooler. What's your opinion?
Turned the heat on to high, pipes out of DCCV 160 an 145 again I thought they would go higher.
Pressures of high and low sides appear good to me. 190 & 45psi.
Ambient temp is 80F with air conditioner on air coming out of vent is 70F.
Not good but does cool the air down slightly.
I hear a slight clicking at the compressor and the guage needles have a slight shake see below, sorry video wont load..
The clicking is not the clutch engaging, clutch stays engaged until I turn the ac off.
I am thinking I good a bad compressor again.
Any thoughts?

 

Video of needle shaking, I think this may mean something but I am not sure what.
Does anyone know what this means?

 

I been having AC problems. I changed the compressor and dryer two years ago, compressor was leaking. Changed the DCCV and condenser this years due to a small accident, vacuumed the system and recharged system with 3 cans of freon. Still having a problem but I think I bought a bad DCCV. I will clamp off the hoses today to see what happens. My question is the needles on the ac gauges shake. Does anyone know what this means if anything?

 

Not trying to bust your behind, but did the original actually fail? Or did you change it on a whim? You didn't really specify, and I want to be sure. What brand DCCV did you install? Some aftermarket brands have dismally poor reliability. If the original was okay and the replacement was bad, you may have inadvertently introduced a new fault into the system.


Okay, we have identified one problem. System capacity is 750g, or 26.5 ounces. If you put in 3 cans at 12 ounces each, that is way too much, something like 36% over. The system will not be happy with so much extra.


Did you begin the test with a cool engine, preferably after sitting overnight? (I'm talking the car sitting, not necessarily you...) If you tried testing with a warm engine, radiant heat from the nearby exhaust will skew the results. Those are not the numbers I would expect to see. They would seem to indicate the valves within the DCCV are stuck partially open, giving neither full heat nor ever shutting off completely.

Before throwing another DCCV at the problem, did you try going for a test drive, with the AC switched off, manual LO selected, and the air directed to the dash vents? Details are in the guide. If the DCCV is shutting off fully when commanded, the vent temperature should be very close to ambient. If considerably higher, the DCCV is not closing fully on at least one side.

If the results are still inconclusive, see post #26 in the guide. You can pinch off the the heater return line (the larger hose of the three) for troubleshooting. If the duct temperature drops, you'd know the DCCV had been letting hot coolant reach the heater core when commanded off.


Problem #2. Low side pressure should be down around 29 PSI. (Typo in the guide, corrected in post #43.) This may be due to the excess refrigerant, but am not sure. Correct the refrigerant quantity and retest. If still high, go back to section #4 of the guide. Pay attention to the part about serpentine belt tension and the clamping ability of the compressor clutch. A bad relay, for example, could be causing this.

For now, don't worry about the high side pressure or any needle fluctuations.

This will point you to post #4 in the guide. You are getting some cooling, but obviously not enough.



I am thinking you shouldn't automatically convince yourself the most expensive component is the problem.

Continue working through the guide, but take your time and complete each step. When troubleshooting, running around like a chicken with its head cut off generally doesn't lead to positive results. Be aware you may have more than one fault. Correct one, retest to identify the next fault, and continue. We already know one problem for sure (too much refrigerant) and possibly a second one (DCCV misbehaving). You could have a third (serpentine belt slipping, just a guess) or a marginal compressor clutch relay. I would exhaust all other possibilities before condemning the new compressor.

 

I am not sure how you broke up my message and added the quotes, but I will copy and past your question and then my answer.

"Not trying to bust your behind, but did the original actually fail? Or did you change it on a whim? You didn't really specify, and I want to be sure. What brand DCCV did you install?"

I tested it using the Infrared method and it appeared the the pipes were too hot with the heater off. Now that I tested the new one and got similar result I can't tell you if the old one was actually bad or not. I also clamped off the big hose today (see photo )and got similar results. Each time I tested the car it sat over night. The car takes 5 - 10 minutes for the instrutment temp gauge to get to mid position. I think by then the pipes are getting warm just by the heat of the engine as they are close to the V8.
Since I was going to be working in that area I decided just to change it out because I had more room to work with since the condensor & dryer were out of the way.
Not sure of the brand, just bought it on-line I think for around $60 most places were over $100.

 

"Okay, we have identified one problem. System capacity is 750g, or 26.5 ounces. If you put in 3 cans at 12 ounces each, that is way too much, something like 36% over. The system will not be happy with so much extra."

Response: At first I added only two cans (24oz) it had little to no effect. Then I added another 3/4 of a can.

 

"Did you begin the test with a cool engine, preferably after sitting overnight?"

answer: yes car sat overnight.

 

I removed some freon so the system has appox 24oz. The static pressures of the service manifold gauges are 50 and 100psi, started the car and they go to zero and 50 psi the needle are stable the compressor stopped clicking but still no cold air.

Yesterday the line coming out to the dryer was cold, today it isn't and the two pipes coming out of the compressor a both hot, 220 and 130 F.

I am still leaning toward the compressor. The one I installed two years ago was a rebuilt one so it could be bad. This time I will buy a new one.

Tomorrow I will start car (DCCV large hose still clamped) measure vent air temp let car warm up and see if the vent temp changes with heater set to low. If vent temp stays close to ambient then I will remove clamp measure vent. Then set heater to High and measure temp. To verify DCCV is working or not.
Then I will add 1/2 can of freon to see what happens.
I will provide an update tomorrow.
Thanks for your help.

 

I'm confused by these numbers. With the engine off, the high and low side pressures will equalize within a few minutes. The PSI numbers for R134a is fairly close to the F temperature, too. In other words, if the car has been sitting for a while on an 65F day, you will see approximately 65PSI on the high and low sides.


More confusion. Zero PSI is WAY low. With the AC on, the normal low value is down around 29 PSI. I've no idea how you're seeing such a low number. And then your high side dropped from 100 to 50? It should have increased, not decreased.

I honestly have no idea what is happening with these numbers. Could there be a problem with your gauge set? Do you have access to another you could try?

Despite the numbers that don't make any sense, I'd still suggest thoroughly investigating the compressor clutch operation before condemning the entire compressor. Please see the section of the troubleshooting guide showing how to use paint marks to check for slippage. I'd certainly want to swap in a known-good relay for the compressor clutch circuit, too.


For giggles, I tested my DCCV on the drive to work this morning. Control panel set manually to LO, fan at low speed, AC switched off, dash vents selected. In that configuration, no hot coolant should be reaching the heater core to raise the outlet temp. Nor would any cooling take place to lower the temp. I should have ambient air going in to the ductwork, no heating nor cooling taking place, and then ambient air exiting via the dash vents. Ambient temp was 60F. The little thermometer in the vent said 62F, so I was very happy with that. Maybe try this simple test and report back. I have noticed you want to do this test in motion, preferably above 30 MPH. If tested while parked or in slow traffic, you tend to get excess warm air coming from the engine. That will skew the results and possibly make it appear a good DCCV is not closing completely.

 

This morning's test it is in order as I did them.
DCCV clamped, AC gauge pressure 60 & 90 psi static, ambient temp 60F, AC off, heater to Low.
Start car, waited until car came to temp, vent temp 65, radiator hose 176
Waited a few more minutes, vent 78, radiator hose 190F. I feel the there is zero water going to heater (hose is clamped).
Remove clamp car still running, heater still on Low, vent temp 81, radiator hose 192F I feel DCCV is working no water getting to heater core.
Turn heater to HIgh, vent immediately jumps over 120F. DCCV definitely opened.
Turn heater to Low, vent jumped to 90, Radiator hose 199, vent temp dropping 89, 88F. I feel DCCV is working fine.
AC on (manual), ac gauges 10 & 130 (needles shaking) vent 79F Got a little cooler, pipe at dryer feel cold.
Checked compressor pipe temps 250 & 160F vent temp 68, rad 210
After a few minutes Pump started clicking ac gauges 75 90 psi vent temp 80F
I will swap out the compressor relay just to try but it appears to be engaging fine.
With the low pressure going high on the AC gauges I still suspect the compressor.

 

I swapped the relay, no change, fog lights did work.

 

I bought a new compressor and dryer, flushed out the system (that's new to me I didn't do that when I installed the rebuilt compressor two years ago).
The old compressor had a two year warranty which they honored. The old compressor could have went bad because I didn't flush out the system, who knows. Installed new components add two cans (24oz) of freon. Now I have cold air, pressure gauges are steady, pressure gauges are 35 & 170PSI ambient temp being 75F. Glad to be driving the car again, it really is a nice car to drive. Although it has it problems and I debate about selling it when I am driving it those feeling go away.

 

It sounds like you’re dealing with quite the challenge with your AC system! It’s frustrating to have your air conditioning act up, especially during a long drive in sweltering heat. The issue of your AC blowing hot air then cold intermittently, and only blowing cold when parked, suggests there are significant problems, especially with the compressor seals.
Given the diagnostic results and the $2,500+ estimate for repairs, your plan to buy the parts yourself and have the shop handle the vacuum and recharge is a smart move. Getting the compressor, PAG oil, and other components for $335.14 is a great deal, especially considering the shop’s price for labor alone. By replacing everything yourself and just paying for the vacuum and recharge, you’re saving a lot of money while still ensuring the job gets done properly. Just make sure you’re comfortable with the replacement process and double-check the compatibility of all the parts you’re buying. It sounds like you’ve got a solid plan, and hopefully, this approach will get your AC back to working efficiently without breaking the bank.

 

Im still curious about your static pressure readings. They should be the same they should be no differential in the pressure between the high and the low if the air conditioner compressor is not running.

In a difference in static pressure means one of two things you gauges are not accurate or you’ve got a blockage someplace. It’s not allowing pressure to equalize. If that was the case, I would go through because the blockage.

Could be a blockage and the resolve that what is static pressures now with the AC off for several hours?

by the way, if you look at your low pressure gauge manifold gauge set, you’ll see the inner ring has a temperature band temperature is the temperature of the 134 and you’ll see it lines up with the specific pressure if the car has been turned off all overnight. The temperature should be the temperature of the ambient air, if it’s been sitting overnight, the temperature at the low pressure port will be the same as the temperature at the high-pressure port so they should not be a difference in pressure

 

He may not have waited long enough? It always takes at least 30-60 minutes to get the pressure to equalize. I thought they should do it much quicker but that's what I have observed on both my Jaguar's.
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