Resolving my 200 LS A/C Problem, please advise.

[lincoln_zero]

Resolving my 2005 LS A/C Problem, please advise.

Hi everyone,

So Here's whats happen/happened in a nutshell. Bought this 2005 LS from a small used car dealer October 2012, dealer said she got it from an Auction. By summer 2013, realized that there is no A/C, but didn't have the time to work on it so didn't tackle the issue. Now as of this year, I took the car to my family mechanic who ran the dye through the lines, after a full week at the Shop they assumed its the Evaporator located in the dashboard.

Today I had time to play with the car. Its 20 degrees Celsius outside, so hard to determine if just outside air is cold or A/C coming in. I turned the A/C on, and its cold, but not much colder than outside. Upon heavy acceleration I noticed that the air got cooler, and when I stopped, it slightly warmed up. So I pulled into Walmart's parking lot, Parked the LS, and began to Rev to 2800 RPM... BAM!! freezing Cold air, much much colder than outside, coming in. Very cool. Not quite 100% there yet, but yes THAT was A/C coming in.
I Let off the throttle, and the air slowly Gradually warms back up to just slightly colder than outside. So I engage the car, select shift into second gear and drove the speed limit at 3500 RPM, BAM freezing air again.

That's the symptom. Any thoughts? Thanks fella's.

 

[LS4me]

Auxiliary pump (does the 2nd gen have one?)? DCCV?

 

[Blueberryyum02]

Auxiliary pump (does the 2nd gen have one?)? DCCV?

Sounds me like the fan is not going into high, at that's why at higher RPMS so it may seem but it's more so more air being pulled thru the condenser on the front. Thus cooling off the refrigerant

 

[lincoln_zero]

I just drove it to town, and when i left my drive way i turned the A/C on and it was making a Hissing sound from inside the vents. It did this for about a minute then stopped. Still not blowing Super Cold.

Also for additional info: Yesterday it was really hot out. In that hot weather the A/C comes out Luke warm.

 

[stugots]

What's your engine coolant level? How many miles.

 

[joegr]

Sounds me like the fan is not going into high, at that's why at higher RPMS so it may seem but it's more so more air being pulled thru the condenser on the front. Thus cooling off the refrigerant

Gen II is electric fan, so it is not effected by engine speed.

 

[joegr]

It doesn't sound like a coolant/DCCV/aux pump problem to me. It sounds like it's the compressor (more likely) or the expansion valve (less likely). Readings for the high and low pressures at idle and at 2500 RPM would help. Also, the hissing sound usually indicates a low refrigerant level. (If true, this will show in the pressure readings.)

 

[lincoln_zero]

It doesn't sound like a coolant/DCCV/aux pump problem to me. It sounds like it's the compressor (more likely) or the expansion valve (less likely). Readings for the high and low pressures at idle and at 2500 RPM would help. Also, the hissing sound usually indicates a low refrigerant level. (If true, this will show in the pressure readings.)

Ok. Well that does make sense but, now its confusing because the mechanics added dye to the system and they checked the pump for a leak, and found nothing. They said the pump does engage.

So the pump is operating, yet the coolant is low. They topped it up twice, but now its hissing which indicates its low? So then it is leaking, but from where? If it was leaking at the pump, wouldnt we see the dye on the pump? Unless something else is playing foul here, like the Evaporator (not sure if its called that) in the dash?

LS has 175,000 kms. Got it at 130,000 kms. A/C did not work at 130k.

Can an obdII scanner get the pressure reading? I have never done this before. Thanks.

 

[BigBalla39213]

Ok. Well that does make sense but, now its confusing because the mechanics added dye to the system and they checked the pump for a leak, and found nothing. They said the pump does engage.

So the pump is operating, yet the coolant is low. They topped it up twice, but now its hissing which indicates its low? So then it is leaking, but from where? If it was leaking at the pump, wouldnt we see the dye on the pump? Unless something else is playing foul here, like the Evaporator (not sure if its called that) in the dash?

LS has 175,000 kms. Got it at 130,000 kms. A/C did not work at 130k.

Can an obdII scanner get the pressure reading? I have never done this before. Thanks.

I recently changed my Compressor and Drier. My A/C blows warm until I'm on the Freeway. It gets cold when I'm at 60 plus, but not Ice Cold. I'm guessing the Expansion Value has some blockage. I will change it soon.

 

[joegr]

...Can an obdII scanner get the pressure reading? I have never done this before. Thanks.

No. (BTW, it's refrigerant, not coolant.)
You'd need a set of pressure gauges, like this.
http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html

 

[Blueberryyum02]

Gen II is electric fan, so it is not effected by engine speed.

Yes I'm aware of the electric fan, was thinking it wasn't going into the first stage speed I have mercury villager which has the ford fan setup with the Nissan motor and trans that would do the same thing and I narrowed it down to the fan, it would come in the second stage which meant the motor was just about to really start cooking itself, but would not come on when it reach temp and the a/c was being used. At first start up.

 

[lincoln_zero]

No. (BTW, it's refrigerant, not coolant.)
You'd need a set of pressure gauges, like this.
http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html

Oh ok I've seen that, my father in law has one. I will check it Tomorrow. Oddly I think it does hold its pressure cause my father in law tried to top it himself and it did hold its pressure (this was the first thing we did before bringing it to the mechanic) But I will do a fresh check tomorrow.

 

[lincoln_zero]

Ok I checked the pressure on the AC lines with help from my father in law.

Engine Idle, it was 74 pounds. Then I reved the engine to 2500 RPM, and it dropped to 20 pounds.

 

[LS4me]

Ok I checked the pressure on the AC lines with help from my father in law.

Engine Idle, it was 74 pounds. Then I reved the engine to 2500 RPM, and it dropped to 20 pounds.

View attachment 828468072

I don't know if this will help.......

Procedure 1 — Ambient Temperature At or Below 38°C (100°F)

NOTE: The system performance can be evaluated and diagnosed by analysis of the compressor suction and discharge pressures. The following procedure is used to determine if the system is operating at normal pressures.

NOTE: The procedure varies depending on the ambient (shop) temperature. If the ambient temperature is 38°C (100°F) or lower, follow procedure 1. If the ambient temperature is over 38°C (100°F), follow procedure 2.

NOTE: If the A/C compressor cycles at any time during this test, refer to the diagnostic table.

Drive the vehicle or run the engine until it reaches normal operating temperature.

Connect a manifold gauge set or refrigerant service center with high-pressure and low-pressure gauges to the refrigerant system.

Set the climate controls.
If equipped with manual climate control, set the A/C controls for normal A/C-PANEL mode, full COOL temperature, FRESH air, HI Blower. If the vehicle has a fresh air/recirc button, set it to FRESH. If the vehicle has an A/C switch or compressor on switch, set it to A/C ON.
If equipped with ATC, set temperature to 15°C (60°F) (lowest possible temp setting) with the dual function disabled (if equipped). Manually set blower on high. If the vehicle has a fresh air/recirc button, set it to FRESH. If the vehicle has an A/C switch or compressor on switch, set it to A/C ON.
If the vehicle is equipped with auxiliary climate control, set the auxiliary controls to full COOL in the PANEL mode at HI blower speed.

Open all vehicle windows and leave the hood open for the test. Open the rear hatch and/or rear doors (if equipped).

Confirm the compressor clutch is engaged and the engine cooling fan(s) are operating or engaged. Allow the vehicle to idle until the suction (low-side) and discharge (high-side) pressures are stable or fluctuate in a range that repeats.

Record the ambient (shop) temperature.

Record the discharge pressure. If the pressure is fluctuating, record the average value.

Determine if the discharge pressure falls within the normal operating limits using the Normal Refrigerant Discharge Pressures chart.

Record the suction pressure. If the pressure is fluctuating, record the average value.

Determine if the suction pressure falls between normal operating limits using the Normal Refrigerant Suction Pressures chart.

Proceed to the diagnostic table.

 

[joegr]

Ok I checked the pressure on the AC lines with help from my father in law.

Engine Idle, it was 74 pounds. Then I reved the engine to 2500 RPM, and it dropped to 20 pounds.

...

74 at idle is too high. 20 at 2500 RPM is a too low. Unfortunately, I really can't tell you much without seeing the high side pressures at the same time. (That's why I linked to a gauge set.) I'm thinking bad compressor, but then I don't have much to go on here...

 

[lincoln_zero]

74 at idle is too high. 20 at 2500 RPM is a too low. Unfortunately, I really can't tell you much without seeing the high side pressures at the same time. (That's why I linked to a gauge set.) I'm thinking bad compressor, but then I don't have much to go on here...

We tested on the Mothers brand new Journey. It would drop to 20 psi when I revved to 2500 RPM, but on its own it would climb back up to 50. Shortly after it would drop to 20 psi, then return to 50 and do this while still keeping it under 2500 RPM.

My LS also drops to 20 PSI when revved at 2500 rpm, but unlike the journey, my LS remains at 20 psi while under 2500 rpm.
I am not sure if that means anything.

I'm trying to give you the data as best as I can. What do you mean "seeing the high pressures at the same time"?

 

[Ranchero50]

Just wait a month, it'll be cold again

Honestly I have no good idea. I would look into the HVAC controls to make sure you aren't losing vacuum to an actuator if they are still using vacuum on the '05's (Don't know). In my very limited experience, the compressor either pumps or it blows apart. If it'as coming on then you have enough pressure in the system, but you don't have any idea how my refrigerant is in it. I'm surprised your shop didn't pump it down and do a full recharge. At least then they would know if the compressor was working. I've never heard of an orifice opening up. I've seen them plug up from trash in the lines but that shows on the gauges real quickly.

On my '05 you can turn the temp all the way down and it will put out the max effort on the cooling ckt. Anything above that and it's blending the warm air with the cold.

 

[joegr]

... What do you mean "seeing the high pressures at the same time"?

The AC system has two distinct sides, the low side and the high side. You are giving the pressures for the low side (suction side of the compressor) only. To really know anything about the system, you need the pressures for both sides at the same time. That's why the AC pressure gauge sets have two gauges and a high side and a low side connection.

 

[joegr]

...I would look into the HVAC controls to make sure you aren't losing vacuum to an actuator if they are still using vacuum on the '05's (Don't know). ...

No LS ever used vacuum for the HVAC. All years were always fully electric.

 

[Ranchero50]

Then he is running out of things to troubleshoot. Again, it looks like he needs to know what the high side is doing.

From my understanding, the AC cycle is pretty simple. Compress a gas with the compressor, cool the hot gas to ambient at the condenser and store it somewhere, drop the pressure (temp) at the orifice, run that cool gas through the evaporator and back to the compressor. I worked on a 10,000 lb ammonia system from the '30's a couple years ago, leaks were great fun to deal with.

 

[joegr]

Actually, it is converted from a gas to a liquid and then back to gas again. The heat transfer happens when the gas becomes liquid (heat out), and when the liquid becomes a gas (heat in - cooling). This explains it better.
http://deneau.info/ls/s6x~us~en~file=s6xc0002.htm~gen~ref.htm

(Scroll down for diagrams)

 

[Broseph]

Bring this back as I have a related issue on my 02. Just finished replacing expansion valve and got good help over in the dash removal thread.

I just charged the system last night and the pressures don’t quite jive.

30psi low / 205 psi high at idle ~90F outside.The system took 40oz which felt high so we removed some to bring it down to 34oz. The high side is right on as it increased and dropped accordingly with ambient temperatures.

The air is coming out ice cold at 37-38 degrees while cruising.

I just can’t figure out why the low side is down about 10 psi from what it should be. I did the electric fan conversion and it’s pulling good air and everything was replaced, compressor, condenser, THX valve and evaporator. Thoughts?

 

[joegr]

...30psi low / 205 psi high at idle ~90F outside.The system took 40oz which felt high so we removed some to bring it down to 34oz. The high side is right on as it increased and dropped accordingly with ambient temperatures...

Wow, that is way overfilled. Too much is even worse than not enough. The correct amount is 28 oz.

At 90 outside, you should see 150 to 190 PSI on the high side, and about 37 to 66 PSI on the low side. This is with the blower on high, set to fresh air in, and all windows open. I think on the 1st gen you are also supposed to have the engine above idle during the test.

With the correct 28 oz refrigerant + 7 oz oil, if the high side pressure is too high, it's an indication that the engine cooling fan is not moving enough air. The low side pressure being too low (with high side being high) is usually an expansion valve problem. That said, as long as it is cooling well, then being a little low on the low side is not that bad. I know that the BWM that I had called for lower low side pressures, and it cooled very well.

 

[Broseph]

Wow, that is way overfilled. Too much is even worse than not enough. The correct amount is 28 oz.

At 90 outside, you should see 150 to 190 PSI on the high side, and about 37 to 66 PSI on the low side. This is with the blower on high, set to fresh air in, and all windows open. I think on the 1st gen you are also supposed to have the engine above idle during the test.

With the correct 28 oz refrigerant + 7 oz oil, if the high side pressure is too high, it's an indication that the engine cooling fan is not moving enough air. The low side pressure being too low (with high side being high) is usually an expansion valve problem. That said, as long as it is cooling well, then being a little low on the low side is not that bad. I know that the BWM that I had called for lower low side pressures, and it cooled very well.

Yep, it was still overfilled. Pulled out 5 more oz to 29 and it sat at 36 and 185