[snowwy66]

Motor running at 2000 rpm for best pressure readings. Come back with results.

Hi side should be at 250psi at 2000 rpm with fan running. Low side around 35ish.

The fact that your compressor is running means you got voltage. There's no science needed for diagnosing.

A bad expansion valve will cause low pressure to be high and high pressure to be low. Your readings indicate bad compressor or overcharged and right now your overcharged.

Drain it down to what I posted and post what the readings are. Start from there.


EDIT:::::: Rereading your post. Your initial readings indicate expansion valve. Do the 2000 rpm first though and post your readings. To confirm.

 

[turboman1]

Motor running at 2000 rpm for best pressure readings. Come back with results.

Hi side should be at 250psi at 2000 rpm with fan running. Low side around 35ish.

The fact that your compressor is running means you got voltage. There's no science needed for diagnosing.

A bad expansion valve will cause low pressure to be high and high pressure to be low. Your readings indicate bad compressor or overcharged and right now your overcharged.

Drain it down to what I posted and post what the readings are. Start from there.


EDIT:::::: Rereading your post. Your initial readings indicate expansion valve. Do the 2000 rpm first though and post your readings. To confirm.

Took the reading at 2000 rpm...

80 psi Low side, while the high side ranged from close to 300 psi right after startup to about 250 after a minute or so.

Decided to remove a little from the system, and once that happened the pressures started pulsating with about a 2 second period. Low would go from about 80 psi to 65 psi and high would go from about 250 psi to 300 psi. Keep in mind the ambient temp is about 103*F today and the car was heat soaked.

The pulsating almost makes me think the pump is failing.

Appreciate the help.

 

[snowwy66]

Motor running at 2000 rpm for best pressure readings. Come back with results. ?

Hi side should be at 250psi at 2000 rpm with fan running. Low side around 35ish.

The fact that your compressor is running means you got voltage. There's no science needed for diagnosing.

A bad expansion valve will cause low pressure to be high and high pressure to be low. Your readings indicate bad compressor or overcharged and right now your overcharged.

Drain it down to what I posted and post what the readings are. Start from there.


EDIT:::::: Rereading your post. Your initial readings indicate expansion valve. Do the 2000 rpm first though and post your readings. To confirm.

Took the reading at 2000 rpm...

80 psi Low side, while the high side ranged from close to 300 psi right after startup to about 250 after a minute or so.

Decided to remove a little from the system, and once that happened the pressures started pulsating with about a 2 second period. Low would go from about 80 psi to 65 psi and high would go from about 250 psi to 300 psi. Keep in mind the ambient temp is about 103*F today and the car was heat soaked.

The pulsating almost makes me think the pump is failing.

Appreciate the help.

Is the compressor cycling off and on? Or constant? Is the fan also cycling off and on?

They don't run constant anymore. Not sure on your model year though.

My sons 16 Mazda stays fan on but my 17 Cruze cycles.

Expansion valves are more common then compressors.

 

[turboman1]

Is the compressor cycling off and on? Or constant? Is the fan also cycling off and on?

They don't run constant anymore. Not sure on your model year though.

My sons 16 Mazda stays fan on but my 17 Cruze cycles.

Expansion valves are more common then compressors.

I'm not sure it is cycling per say, but it is commanding more/less/more/less volume flow... so you could say it has the effect of cycling. I don't think this has a clutch on it as there is never that apparent clutch engagement sound like on older vehicles. I wouldn't think the pressure would spike so high, ~300 psi, before it "cycles" and goes back to 250 psi... that happens quickly and repeats about every 2-3 seconds. That is the first time that has happened also on the vehicle b/c you can noticeable hear the motor pull down for a second and then unload. Started after I removed a little from the system.

 

[snowwy66]

I'm not sure it is cycling per say, but it is commanding more/less/more/less volume flow... so you could say it has the effect of cycling. I don't think this has a clutch on it as there is never that apparent clutch engagement sound like on older vehicles. I wouldn't think the pressure would spike so high, ~300 psi, before it "cycles" and goes back to 250 psi... that happens quickly and repeats about every 2-3 seconds. That is the first time that has happened also on the vehicle b/c you can noticeable hear the motor pull down for a second and then unload. Started after I removed a little from the system.

If it were me. And I wasn't exactly sure how much was in the system. And thought there was possible air in the system. I'd drain, evacuate, and recharge with the proper amount. And see what happens. BUT. I have all the proper equipment to do that. You don't.

New regulations no longer allow top offs. NOW, it's a complete drain and refill. And I have no idea what the going rate is these days.

Sounds like you're stuck with visiting a shop for diagnosis and repair.

I"m all outta ideas. Someone else may come along with something to look at.

It could be an electrical issue somewhere in the entire system. Gone are the days of simple power routing. Or a component failure.

It could be a compressor but I'm seeing expansion valves all too common these days.

 

[jblackburn]

The expansion valve on mine caused absurdly high high side pressures and a screaming engine fan. Air out of the vents never got much in the way of cool.

I have no idea what the pressures were; mine was covered under the B2B warranty long ago. That car also had the compressor replaced shortly before - as apparently compressor failures were quite common on the 2011/early 2012 Cruzes.

We did just have the VW evac & refilled, and a solenoid changed in the compressor that meant removing it to get to the back side of it. It was ~$250 for all of it.

 

[turboman1]

So I replaced the compressor, condenser, and the expansion valve.

A/C is working part of the time.

Does anyone know if the lower temperature sensor near the radiator outlet can effect when the compressor should cycle?

I saw the high pressure sensor, but is there a low pressure sensor on these cars?

Just for completeness, at 100*F with about 10% humidity... when the compressor is pumping the low side is 50 psi and high is 250 psi.

 

[Maqcro1]

I don’t think the ECT would effect the a/c system performance wise. I guess it could shut down the compressor if the car was overheating due to a false reading.

I’d have to double check the pressure table to see if that’s right but just a quick guess that seems to be about the right pressure on both sides.

 

[turboman1]

I'm beginning to think that lower ECT sensor has drifted/failed and when the thermostat lets coolant flow to the radiator it eventually gets to that temperature sensor giving the computer a higher coolant temp than actual. It makes sense as to why they would use that sensor to fail safe the motor. Turning off the A.C from it would allow cooler air to hit the radiator than form being heated up thru a hot condenser. This is just a theory, hopefully someone has some 'inside' information on the logic of that temp sensor and what looks at it.

 

[snowwy66]

Low pressure sensor kicks the compressor on at 50 psi. Shuts the compressor off if low pressure drops to 20.
Hi pressure sensor shuts the compressor off I THINK at 375 psi. Fan kicks on at I THINK either 335 or 350 psi. I"ve never overcharged a system so I"m not exactly sure on the HI cutoff. And I'm not sure if there's one or two hi pressure switches.

250 is perfect for the high side.
50 is too high for the low side. Read post #2.

Trouble shooting chart indicates faulty compressor.

None of us have any idea how you assembled the parts and how you charged the system though. Having air in the system can make pressures whacky.

In case your car is missing the label. The gen1's only hold 20 oz. of freon.

Did you add the correct amount of oil to the compressor AND the evaporator? It's been decades since I've bought parts so I have no idea if oil comes included or not these days. It didn't use too.

 

[turboman1]

Anyone willing to take a resistance measurement across their lower radiator temperature sensor at ambient and operating temperature?

 

[snowwy66]

Your radiator temps aren't going to effect your low pressure being too high.

Post a pic of what your gauges look like WITHOUT hooked and no freon in the lines. Let's make sure your gauges are calibrated.

Then post a video of what your gauges are doing. Engine at 2000 rpm. At least 2 minutes so we can see what your compressor and radiator fan are doing.

You can probably create a youtube account if you don't have already and upload your video and post a link to it.

 

[turboman1]

Low pressure sensor kicks the compressor on at 50 psi. Shuts the compressor off if low pressure drops to 20.
Hi pressure sensor shuts the compressor off I THINK at 375 psi. Fan kicks on at I THINK either 335 or 350 psi. I"ve never overcharged a system so I"m not exactly sure on the HI cutoff. And I'm not sure if there's one or two hi pressure switches.

250 is perfect for the high side.
50 is too high for the low side. Read post #2.

Trouble shooting chart indicates faulty compressor.

None of us have any idea how you assembled the parts and how you charged the system though. Having air in the system can make pressures whacky.

In case your car is missing the label. The gen1's only hold 20 oz. of freon.

Did you add the correct amount of oil to the compressor AND the evaporator? It's been decades since I've bought parts so I have no idea if oil comes included or not these days. It didn't use too.

Thanks for the reply.

I evacuated the system for a little over 1hr, unhooked and let it sit for 30 minutes -> Held a 25 mmHg for all 30 minutes. Where I live the relative humidity is next to nothing right now in the summer.

Compressor came prefilled with 150cc of PAG46 oil.

Keep in mind the ambient temp was around or just above 100*F. From a couple pressure charts I have seen 50-55psi on the low side is normal for that ambient temp.

I can tell you the gauges are zeroed with all valves open.

Just letting the car sit and run the A/C stays cold the entire time. It isn't until I start driving and putting a load on the motor (not flooring it every where but brisk acceleration < 95% throttle input), that it eventually kicks off. If I take it really easy and let enough air pass thru the front without much heat being generated in the cylinders it seems come back on again. Hence the idea of thinking that lower radiator temp sensor is causing some problems here.

I was able to take a reading right after it decided to kick back on and pressures were the same 250 psi high and 50 psi low.

I can try and get a video later today if you think you can glean anything from it, but those pressures stay pretty constant and the A/C runs continuously at idle.

 

[snowwy66]

Thanks for the reply.

I evacuated the system for a little over 1hr, unhooked and let it sit for 30 minutes -> Held a 25 mmHg for all 30 minutes. Where I live the relative humidity is next to nothing right now in the summer.

Compressor came prefilled with 150cc of PAG46 oil.

Keep in mind the ambient temp was around or just above 100*F. From a couple pressure charts I have seen 50-55psi on the low side is normal for that ambient temp.

I can tell you the gauges are zeroed with all valves open.

Just letting the car sit and run the A/C stays cold the entire time. It isn't until I start driving and putting a load on the motor (not flooring it every where but brisk acceleration < 95% throttle input), that it eventually kicks off. If I take it really easy and let enough air pass thru the front without much heat being generated in the cylinders it seems come back on again. Hence the idea of thinking that lower radiator temp sensor is causing some problems here.

I was able to take a reading right after it decided to kick back on and pressures were the same 250 psi high and 50 psi low.

I can try and get a video later today if you think you can glean anything from it, but those pressures stay pretty constant and the A/C runs continuously at idle.

The ac works better with engine running and driving down the road. It loses efficiency when sitting idle at a light. The pressures drop. And with todays cars. The fan don't kick on till high pressure gets high enough. Kicks off when hi pressure drops.

THUS, the 2000 rpm charging of the system and the 250 psi on hi with the fan running. Taking readings at idle is not a good idea as your car spends 90% of it's time driving down the road.
Now, some might argue that the engine also don't run at 2000 rpm in today's world. Usually 1500 or less.
It's how I've been doing it WITHOUT a machine for over 30 years.

The fact that you're working at idle but not so much driving down the road. And your low pressure being too high. Leads me to believe the system is overcharged. And I don't know what method you used. I"m guessing cans though. Good way to allow air in the system.

I also wouldn't put much attention to the charts. They're close for when 134 first came out. Back in 1994. They're not accurate for today. 350 psi for the dessert heat is way too much. And 155 for the spring isn't enough. Yes, pressures will vary. But 200 psi is a very wide range between spring and summer. That's not realistic.

If I get chance and have someone to help me. I"ll shoot a video of what my car does. It was serviced in accordance with the new regs. By a retired mechanic that just renewed his EPA certificate. MEEEEEE.
And I have all the proper equipment to perform such a task. Including a 30 lb cylinder of freon instead of the cans. NO AIR in the system what so ever.

This isn't to brag either. I was trained. You guys haven't.

The video won't happen today though. As the temps aren't that hot this weekend. It wouldn't be a fair comparison to show you down in Phoenix. I'll have to wait for Mother Nature to get off her arse and warm up the rest of the country. We should be approaching 100 by now and we're still screwing around with the 60's and snow in the mountains.

I also wouldn't worry about humidity. You're in dry air country. Not once have I ever pulled up a weather report to service a car. I don't think any mechanic cares about the weather.

 

[jblackburn]

What you are describing actually sounds quite normal. The Cruze disengages the AC compressor way earlier than WOT to aide acceleration. I would say it's somewhere actually around 3/4 throttle on the Gen 1 (that one was a manual).

But yeah, try holding at 2000 and see if it kicks out.

 

[turboman1]

The ac works better with engine running and driving down the road. It loses efficiency when sitting idle at a light. The pressures drop. And with todays cars. The fan don't kick on till high pressure gets high enough. Kicks off when hi pressure drops.

THUS, the 2000 rpm charging of the system and the 250 psi on hi with the fan running. Taking readings at idle is not a good idea as your car spends 90% of it's time driving down the road.
Now, some might argue that the engine also don't run at 2000 rpm in today's world. Usually 1500 or less.
It's how I've been doing it WITHOUT a machine for over 30 years.

The fact that you're working at idle but not so much driving down the road. And your low pressure being too high. Leads me to believe the system is overcharged. And I don't know what method you used. I"m guessing cans though. Good way to allow air in the system.

I also wouldn't put much attention to the charts. They're close for when 134 first came out. Back in 1994. They're not accurate for today. 350 psi for the dessert heat is way too much. And 155 for the spring isn't enough. Yes, pressures will vary. But 200 psi is a very wide range between spring and summer. That's not realistic.

If I get chance and have someone to help me. I"ll shoot a video of what my car does. It was serviced in accordance with the new regs. By a retired mechanic that just renewed his EPA certificate. MEEEEEE.
And I have all the proper equipment to perform such a task. Including a 30 lb cylinder of freon instead of the cans. NO AIR in the system what so ever.

This isn't to brag either. I was trained. You guys haven't.

The video won't happen today though. As the temps aren't that hot this weekend. It wouldn't be a fair comparison to show you down in Phoenix. I'll have to wait for Mother Nature to get off her arse and warm up the rest of the country. We should be approaching 100 by now and we're still screwing around with the 60's and snow in the mountains.

I also wouldn't worry about humidity. You're in dry air country. Not once have I ever pulled up a weather report to service a car. I don't think any mechanic cares about the weather.

A video of what yours is doing would be helpful. I'll try and get one later today of mine.

I charged with a 30 lb can also. So your thinking the low side should be around 35 psi at that 100*F ambient?

 

[turboman1]

What you are describing actually sounds quite normal. The Cruze disengages the AC compressor way earlier than WOT to aide acceleration. I would say it's somewhere actually around 3/4 throttle on the Gen 1 (that one was a manual).

But yeah, try holding at 2000 and see if it kicks out.

I am at maybe 1/3 throttle, guess briskly to me is relative with all the snow birds and slow they drive ha.

 

[snowwy66]

The ac works better with engine running and driving down the road. It loses efficiency when sitting idle at a light. The pressures drop. And with todays cars. The fan don't kick on till high pressure gets high enough. Kicks off when hi pressure drops.

THUS, the 2000 rpm charging of the system and the 250 psi on hi with the fan running. Taking readings at idle is not a good idea as your car spends 90% of it's time driving down the road.
Now, some might argue that the engine also don't run at 2000 rpm in today's world. Usually 1500 or less.
It's how I've been doing it WITHOUT a machine for over 30 years.

The fact that you're working at idle but not so much driving down the road. And your low pressure being too high. Leads me to believe the system is overcharged. And I don't know what method you used. I"m guessing cans though. Good way to allow air in the system.

I also wouldn't put much attention to the charts. They're close for when 134 first came out. Back in 1994. They're not accurate for today. 350 psi for the dessert heat is way too much. And 155 for the spring isn't enough. Yes, pressures will vary. But 200 psi is a very wide range between spring and summer. That's not realistic.

If I get chance and have someone to help me. I"ll shoot a video of what my car does. It was serviced in accordance with the new regs. By a retired mechanic that just renewed his EPA certificate. MEEEEEE.
And I have all the proper equipment to perform such a task. Including a 30 lb cylinder of freon instead of the cans. NO AIR in the system what so ever.

This isn't to brag either. I was trained. You guys haven't.

The video won't happen today though. As the temps aren't that hot this weekend. It wouldn't be a fair comparison to show you down in Phoenix. I'll have to wait for Mother Nature to get off her arse and warm up the rest of the country. We should be approaching 100 by now and we're still screwing around with the 60's and snow in the mountains.

I also wouldn't worry about humidity. You're in dry air country. Not once have I ever pulled up a weather report to service a car. I don't think any mechanic cares about the weather.

A video of what yours is doing would be helpful. I'll try and get one later today of mine.

I charged with a 30 lb can also. So your thinking the low side should be around 35 psi at that 100*F ambient?

When everything is working properly. 35ish and 250ish. No matter what vehicle. In 100 degrees.

My son's Mazda was done with the new regulations. He came in at 275.

If in cooler weather. Like 80 or 70. Bring the high down about 10 to 15 psi. Southern border heat. 120 degrees. Add upwards of 10 to 15 psi.

So basically 250 +/- 10 to 15 and you won't go wrong.

Thursday supposed to hit 90. I'll try to get video.

I also have digital gauges. Plus harborfreight needle gauges.

 

[turboman1]

When everything is working properly. 35ish and 250ish. No matter what vehicle. In 100 degrees.

My son's Mazda was done with the new regulations. He came in at 275.

If in cooler weather. Like 80 or 70. Bring the high down about 10 to 15 psi. Southern border heat. 120 degrees. Add upwards of 10 to 15 psi.

So basically 250 +/- 10 to 15 and you won't go wrong.

Thursday supposed to hit 90. I'll try to get video.

I also have digital gauges. Plus harborfreight needle gauges.

Video of what the gauges are doing.

https://youtu.be/W52mAiDRnj4