A/C questions, newer car - Chevelle Tech
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post #1 of 20 (permalink) Old Jun 28th, 20, 2:53 AM Thread Starter
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A/C questions, newer car

So yesterday it was 104+ here, and I noticed driving my wifes car, 2009 Toyota Camry, that the air wasn't cold (never had the A/C serviced)... Cool, but not cold... later that same day, i swear it was even warmer...

I dug out my thermometer and placed it in the vent this morning, and it read 90-95 degrees! This was with Max A/C... Then as I was playing with the thermometer, I noticed the passenger side vents were cool... I measured those (in the center stack) at 65 degrees... Funny, two vents, side by side in the center, and one has 65 degree air and the other is significantly hotter... I would have figured they had a common "feed" from the system, I guess not. Its a basic Camry, so no "dual zone" control...


So Yesterday afternoon, I "rented" (free tool rental at O'Reilly's) an A/C manifold set and bought a 1 pound can of refrigerant (just plain 134A, no "stop leak", etc)...

Watched a few You Tube videos and spent the night at a Holiday Inn (okay, kidding on that part). So this morning I hook it up, and I am getting around 22 psi low and 100 psi high, at both idle and about 2500... It was about 90 degrees in the garage.

So I added some 134 A (no scale, so I just added a little until I had the pressures up to 22/205 at 2500 (40/160 at idle). All vents are cold, at 50 degrees...

Still not sure why the 65 semi-cool wasn't evenly distributed...



So then I proceeded to check the A/C on my '97 S10. The A/C quit 2 years ago... Checked, and the gauge read 10 psi (both low/high, idle and ~2000+). So I put the rest of the can in...

After a few minutes of adding a little at a time, the compressor clutch finally engaged (I guess it has a low pressure switch... I then went and bought bought another can, but it would only take about half of that...

Took a while, but I was able to get a stable 50 psi low and 130-170 high at 2000+ rpm. The clutch would cycle every 4-5 seconds, and with it, the pressure fluctuated from 130 to 170 psi... But the air coming out of the vent was still 120 degrees!!! It was only about 90 degrees ambient today... I have a new receiver/dryer, oil and an o-ring assortment sitting on the shelf but I wanted to make sure I didn't have a leak, and locate it first before opening and installing the new dryer... The truck is older and I maybe drive 100 miles per year, so not really worth taking it to a shop... Thankfully in the summer, I usually take it out early morning (to pick up landscape bark, rock, lumber, gas for the mower, manure or car parts)...

Any suggestions on the truck?

Once you go RAT, you never go back...
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post #2 of 20 (permalink) Old Jun 28th, 20, 8:16 AM
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Rick
 
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Re: A/C questions, newer car

Sounds like a "blend door" problem in your S10. The door is an air mixing valve to add in heat and it sounds like yours is stuck on all heat. There could be a DTC code for this that does not throw a Check Engine light. Some of these actuators run by vacuum and I will bet that you are not the only person to have ever had this problem.

A search could reveal how to fix it.

Rick

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post #3 of 20 (permalink) Old Jun 28th, 20, 2:01 PM
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Re: A/C questions, newer car

Here is my thoughts, on the S10, when you added refrigerant, the system already had some plain air in it and you added some freon, probably making things worse. My suggestion, recover the existing freon and install those A/C parts with the proper amount of oil and evacuate the system and let it sit overnite under a vacuum and see how it holds, good luck with your system!!
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post #4 of 20 (permalink) Old Jun 28th, 20, 2:40 PM Thread Starter
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Re: A/C questions, newer car

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Originally Posted by LeoP View Post
Here is my thoughts, on the S10, when you added refrigerant, the system already had some plain air in it ...
I was kind of thinking this, but the system had 10+ psi in it, and therefore how could atmospheric air "leak" INTO the system? I hooked up the gauges, and turned the valves and the needles clearly moved from zero to 10...

I was expecting it to be completely empty. I had it serviced and a cracked line replaced about 4 years ago, then within a year, it failed...

Once you go RAT, you never go back...
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post #5 of 20 (permalink) Old Jun 28th, 20, 2:43 PM
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Re: A/C questions, newer car

Your low side pressure is too high. I not sure, but I think the 97 had an orifice tube system. You should replace this tube. It may be plugged causing the high low side pressures. Check the entire system for oily or dirty components. A freon leak is oily and collects dirt. You can put you hand on the low side components. If they are cold and the temps from the vents are high, you may have vent door issues or hot water is still flowing through the heater. There may be a shut off valve for the coolant that is not closing completely. You can plug the coolant line to the heater to see if this is causing elevated temps. But right now, your pressures indicate too high on the low side.
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post #6 of 20 (permalink) Old Jun 28th, 20, 10:18 PM
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Re: A/C questions, newer car

(but right now, your pressures indicate too high on the low side) Hence my advice about having air in the system, taking up room that refrigerant could be using!!
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post #7 of 20 (permalink) Old Jun 29th, 20, 12:58 AM
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Re: A/C questions, newer car

Since you need to open the system, you should replace the orifice tube along with the other parts you have.

https://www.carparts.com/details/Che...E&gclsrc=aw.ds



I need to correct my previous post. Symptoms of a Defective AC Orifice Tube:

More specifically the low side will show below normal low pressure readings. ... However, when you have a high side gauge connected and the tube is blocked you'll see higher than normal high side pressure readings. I don't think yours is plugged, but it's a good idea to replace it when opening the system. There is a screen on it that can become plugged over time and reduce cooling.
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post #8 of 20 (permalink) Old Jun 29th, 20, 2:44 AM Thread Starter
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Re: A/C questions, newer car

Quote:
Originally Posted by DUTCH MAX HEADWORK View Post
Your low side pressure is too high. I not sure, but I think the 97 had an orifice tube system. You should replace this tube. It may be plugged causing the high low side pressures. Check the entire system for oily or dirty components. A freon leak is oily and collects dirt. You can put you hand on the low side components. If they are cold and the temps from the vents are high, you may have vent door issues or hot water is still flowing through the heater. There may be a shut off valve for the coolant that is not closing completely. You can plug the coolant line to the heater to see if this is causing elevated temps. But right now, your pressures indicate too high on the low side.
Too high on the low side? Do you know the Low and high pressure ranges?

I couldn't find specific info for my vehicle,

But found several different tables on-line for 134A, and for 90 degree day, they all said 45-55 psi Low and 250-270 high...


I'd recheck for dirty parts (leak), but haven't noticed anything (I cleaned the engine when I replaced the intake gasket about 300 miles ago), and it pretty clean right now...

Thanks


I was reading a lot about the air door actuator, and seems thats a pretty common part to fail... I just haven't taken the time to diagnose further...

Once you go RAT, you never go back...
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post #9 of 20 (permalink) Old Jun 29th, 20, 4:13 AM
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Re: A/C questions, newer car

Hi
Vehicle over 60,000miles evaporator needs cleaning
At that point change the TX valve and reseal pipes with R134a O rings green [lube all o rings ]
Remove and inspect// replace orifice tube

Check for compressor discharge hose twists on ferrule connection

replace o rings discharge and suction hose

Remove compressor and reoil , check clutch clearance adjust or replace compressor

clean condenser ,check cooling fan operation

Toyota Camry should have a Nippon Denso air con . These are some of the best Air con out there .

NB compressor seals donot like sitting for long periods
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post #10 of 20 (permalink) Old Jun 29th, 20, 8:27 AM
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Re: A/C questions, newer car

You wont find any vehicle specific air conditioning high and low pressure values. This is because these numbers depend on whatever the outside air temperature is and the type of refrigerant.

I keep a paper copy of an R134 refrigerant pressure chart with my AC gauge kit. Plenty of these charts out there on the Internet.

Rick

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post #11 of 20 (permalink) Old Jun 29th, 20, 8:57 AM
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Re: A/C questions, newer car

HI
Pressure temp charts are for calculations not running pressures

Low side ideally should be 28psi WHY ---because 134a will freeze below this --refer pt chart
low side depends on compressor size evap size and tx valve size

High side cooling to constant 150-160 psi at 110--115f is common in large well designed coach aircons ,, in automotive its common to see 250psi in 100 f weather

Autos are poorly designed and often have very elevated high pressures which impacts performance A REAL LOT.
high pressures depend on condenser size .
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post #12 of 20 (permalink) Old Jun 29th, 20, 10:13 AM
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Re: A/C questions, newer car

Quote:
Originally Posted by 1966_L78 View Post
I was kind of thinking this, but the system had 10+ psi in it, and therefore how could atmospheric air "leak" INTO the system? I hooked up the gauges, and turned the valves and the needles clearly moved from zero to 10...

I was expecting it to be completely empty. I had it serviced and a cracked line replaced about 4 years ago, then within a year, it failed...
Just a thought about that .....
There could have been some residual refrigerent still in the gauge's and the lines,since the adapters are self sealing when you remove them from a system.That could throw you a curve ball making you think the system was sealed with about 10 PSI still sitting in it.

John
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post #13 of 20 (permalink) Old Jun 29th, 20, 12:16 PM
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Re: A/C questions, newer car

Quote:
Originally Posted by swampy 6x6 View Post
HI
Pressure temp charts are for calculations not running pressures

Low side ideally should be 28psi WHY ---because 134a will freeze below this --refer pt chart
low side depends on compressor size evap size and tx valve size

High side cooling to constant 150-160 psi at 110--115f is common in large well designed coach aircons ,, in automotive its common to see 250psi in 100 f weather

Autos are poorly designed and often have very elevated high pressures which impacts performance A REAL LOT.
high pressures depend on condenser size .
28PSI suction pressure is way too low for normal operation.

.
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post #14 of 20 (permalink) Old Jun 29th, 20, 1:18 PM
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Re: A/C questions, newer car

Quote:
Originally Posted by 1966_L78 View Post
Toyota

Still not sure why the 65 semi-cool wasn't evenly distributed...


Any suggestions on the truck?

Fyi - i have a toyota tacoma, and it too has weirdly different vent temps......like the drivers side vent is colder than all the rest, which makes no sense since its furthest from the evaporator.

Like others have mentioned, it sounds like u have a blend door issue. If you start the truck when it is cold, and have some cold air at the vents before the coolant starts circulating through the heater core, that would pretty much confirm the blend door theory. Every spring i get a call from truck drivers about their AC not working, and every spring i have to remind them to close the heater valves to stop hot water from going in the cab. Heater core putting out heat into the system will always "win" over the AC.

On the truck, you may just want to loop the heater hoses, or put a valve on one of the heater hoses, preferably the one coming into the heater core, but really either will do. Sometimes getting to those blend doors, and the controls is a bit PITA. If you want a real quick solution, just use something like a soft jaw vice grip to clamp the one heater hose.
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post #15 of 20 (permalink) Old Jun 29th, 20, 4:20 PM Thread Starter
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Quote:
Originally Posted by 71350SS View Post
Just a thought about that .....
There could have been some residual refrigerent still in the gauge's and the lines,since the adapters are self sealing when you remove them from a system.That could throw you a curve ball making you think the system was sealed with about 10 PSI still sitting in it.
Nope, I had just “serviced “ the Camry and had already disassembled the hoses to put them back in the case. And I know there was zero psi.

Following advice, I hooked up the hoses to the system, and then slowly turned the hose valve ( at the hi and like ports, watched the gauges, and clearly saw them jump from 0 to 20 psi as the hose valve pushed on/ activated the Schroeder valve...

The high gauge went through the same procedure, going from zero to 10 as I turned the valve... this was with the engine off, as my thoughts were low or no refrigerant...

Once you go RAT, you never go back...
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