97 chevy crew cab freon capacity

[Trucker2k16]

So if the first picture it was 65 outside, 25 low and 170 high...
The low is barely in the range but on low part of it, and high is too high.
So restricted valve would be my guess.

How far down did you vacuum it and for how long? Did you replace the dryer?

Are you reading the large black numbers? The r134a numbers are in the blue and red. Vacuum was to 30hg and for a hour it only dropped a half pound is 3 days before i charged the system with the 3 12 oz cans a total of 36 which is what it calls for

 

[Will L.]

Ha! Yeah I did. Looked at it like my old gauges which outside numbers were 134 on. Good catch.
So 30/120. So high side is still lower than it should be if it was 65 outside. The spread between low and high still isn’t where it should be. If it is blowing cold enough and removing enough humidity that you are happy with it, leave it. It isn’t hurting anything.
But you definitely can improve 10-15% better than it is.

If you held near perfect vacuum 3 days- you removed 100% of the moisture. Obviously have the correct amount of refrigerant in there. If you added the correct amount of oil would be the other possibility, Assuming you did- then you restricted valve is the only thing left other than if you aren’t getting air flow over the outside coil. Measuring two sides of the condenser would tell that.

 

[Trucker2k16]

Ha! Yeah I did. Looked at it like my old gauges which outside numbers were 134 on. Good catch.
So 30/120. So high side is still lower than it should be if it was 65 outside. The spread between low and high still isn’t where it should be. If it is blowing cold enough and removing enough humidity that you are happy with it, leave it. It isn’t hurting anything.
But you definitely can improve 10-15% better than it is.

If you held near perfect vacuum 3 days- you removed 100% of the moisture. Obviously have the correct amount of refrigerant in there. If you added the correct amount of oil would be the other possibility, Assuming you did- then you restricted valve is the only thing left other than if you aren’t getting air flow over the outside coil. Measuring two sides of the condenser would tell that.

View attachment 64586

Total 8 oz thru out the whole system and the condenser doesn't het hot and a welding glove will stay on the grille so air flow isnt a issue can say this within 5 mins it gets pretty cold on hi

 

[Will L.]

Yeah, so this is a case of if you want more performance- suck it down, remove valve, flush it, new valve, and redo oil/ r134a and you should hit the numbers. Otherwise run it.

 

[Trucker2k16]

Yeah, so this is a case of if you want more performance- suck it down, remove valve, flush it, new valve, and redo oil/ r134a and you should hit the numbers. Otherwise run it.

What valve?

 

[Will L.]

Valve being fixed orifice tube if that’s what you are still running or vov (variable orifice valve).
If tube and it was new- something is restricting it. People changing the tube 2-3 times in a row is when they usually give up or change to the vov.
I could swear someone on here showed the change over years ago.

 

[Trucker2k16]

Valve being fixed orifice tube if that’s what you are still running or vov (variable orifice valve).
If tube and it was new- something is restricting it. People changing the tube 2-3 times in a row is when they usually give up or change to the vov.
I could swear someone on here showed the change over years ago.

Gotcha yea i shouldn't be having a issue there at lease better not i got over 1000 bucks in this a/c this go round i didnt cheap out on anything lol

 

[WarWagon]

Are you running the VOV ($25) or a fixed orface tube ($1.99) ?

Is the blower fan on high?

A yes to either of those changes the context of the advice/rant below.

To me it's not moving much heat as I am used to seeing 160 degree condenser temp around 250 psi head pressure when it's well over 100F out.

I would consider the low pressure switch isn't working properly anymore at the indicated on the gauge below freezing temp. That switch is to keep the evaporator from freezing up. It can become a solid brick of ice with zero airflow.

The VOV, when I got one that wasn't defective blocked solid and actually worked, was night and day difference colder at idle. R134a Krap gas quits over 105 degrees due to high heat load and lack of enough condenser airflow. But ... spare me other changes and simply and use a better more efficient gas. Short of that major kludges to overcome Beancounter FOT systems used with R134a way past their expiration date of R12. Getting the damn fan moving air over the condenser with an obsolete spring thermal fan clutch is also a major AC performance compromise. Any hot air recirculation over the condenser hurts performance. On a system that is near redline overheating at 160 degrees condenser temp, Oh! I have a sitting on a MI snowbank engineering idea: lets put a couple of oil coolers running over 200F in front of the condenser. When the heatwave hit Detroit lately they redesigned a HVAC system on late model RAM pickups...

Look at a mere 20 degree rise over 160F on your high side gauge. Anything over 400 psi is looking to blow something out on the high side. For temperature contrast the AC system goes "Pop!" before the engine thermostat even opens...

VOV reference from the inventor of the FOT system trying to fix the evil his system causes with R134a. It was 'good enough' but more importantly cheap enough with R12.

VOV Part 1: Interview with VOV inventor, Dick Kozinski

 

[Trucker2k16]

Are you running the VOV ($25) or a fixed orface tube ($1.99) ?

Is the blower fan on high?

A yes to either of those changes the context of the advice/rant below.

To me it's not moving much heat as I am used to seeing 160 degree condenser temp around 250 psi head pressure when it's well over 100F out.

I would consider the low pressure switch isn't working properly anymore at the indicated on the gauge below freezing temp. That switch is to keep the evaporator from freezing up. It can become a solid brick of ice with zero airflow.

The VOV, when I got one that wasn't defective blocked solid and actually worked, was night and day difference colder at idle. R134a Krap gas quits over 105 degrees due to high heat load and lack of enough condenser airflow. But ... spare me other changes and simply and use a better more efficient gas. Short of that major kludges to overcome Beancounter FOT systems used with R134a way past their expiration date of R12. Getting the damn fan moving air over the condenser with an obsolete spring thermal fan clutch is also a major AC performance compromise. Any hot air recirculation over the condenser hurts performance. On a system that is near redline overheating at 160 degrees condenser temp, Oh! I have a sitting on a MI snowbank engineering idea: lets put a couple of oil coolers running over 200F in front of the condenser. When the heatwave hit Detroit lately they redesigned a HVAC system on late model RAM pickups...

Look at a mere 20 degree rise over 160F on your high side gauge. Anything over 400 psi is looking to blow something out on the high side. For temperature contrast the AC system goes "Pop!" before the engine thermostat even opens...

VOV reference from the inventor of the FOT system trying to fix the evil his system causes with R134a. It was 'good enough' but more importantly cheap enough with R12.

VOV Part 1: Interview with VOV inventor, Dick Kozinski

Acdelco tube and yes max and high im also running a aluminum radiator and a duramax fan and fan clutch

 

[THEFERMANATOR]

To me it looks like excess oil or restricted orifice. Even on a hot 90-95 degree day my high side normally levels off around 175 with a low side around 40 idling. For a single air system your high side shouldn't get that high on one of these systems.

 

[Will L.]

So yeah, with the proper charge quantity in the system and seeing your high pressure - that orifice tube is not happy. Mass production woes most likely.
My suggestion is run it like that until you are fed up with dropping performance and rip out that tube to try again or swap to vov.

 

[Will L.]

@THEFERMANATOR - ya quick type sniped me! Haha

The super cheap-made for low cost of production- orifice tube...
That vov is the only ‘fix’ I know of besides trying 3-4 in a row until one works good- which is how we solved it in the fleet back in the 90’s. 300 trucks meant have 50 tubes on hand. We had an a/c machine that had dedicated empty tank that we could put back into the same truck so 100% of oil and refer removed went back in each time. I can’t imagine trying to do it without that- so my answer is 100% flush and start over with new oil and refer each time. So $$$$$.

Is there a super quality tube available anywhere even if it costs like $100?

Any better solution than vov?

 

[WarWagon]

duramax fan and fan clutch

In cold weather it's best to not mess with what you have. I assume it's blowing ice out the vents? The gauge readings were at 76F or 65F degrees out? Was the clutch cycling at all? To me it's either cold weather or the low pressure switch isn't kicking out in time. This temp is a "winter day" to me.

Can you elaborate on how you flushed the system and added oil? Note some new compressors come pre-filled with a full oil charge and some are dry.

Engine cooling... I recall reading the Duramax fan clutch comes on at a higher temp than the 6.5 clutches did. Do you mean the spin on fan clutch for a 6.5? Low temp fan clutch by Kennedy Diesel?

Any better solution than vov?

Looks like the fan clutch is moving a lot of air at idle. Less than 5 years old and a low temp fan clutch by Kennedy Diesel helps. At idle the Duramax fan wins over the 9 blade steel.

A electric aux pusher fan wired to come on with the compressor helps.

Insulate the "cold" line from the condenser orface tube to the firewall evaporator.

Insulate the accumulator - in fact some GM stuff has/had this foam overwrap from the factory. Typical: did it get ruined and tossed with accumulator replacement?

Bypass the heater core - some GM vehicles like, if I recall correctly, 1995 Yukon already had this valve from the factory.

Kick the idle up to 1200 RPM if you are waiting in a parking lot.

Coat the condenser with a Thermal Dispersant. Same with evaporator.

Not sure if a better more efficient compressor is available vs. the 1997 style compressor he has.

Move the hot oil coolers behind the condenser.

I know you don't like alternative flammable refrigerant. However it's night and day over this inefficient R134a gas esp. at higher outside temps. If you are in a 105 degree parking lot out in the dry dessert... The idling vehicle with water dripping out the AC drain isn't running 134a. (Late model vehicles appear to have R134a finally figured out so there is no need.) Short of this, again, more airflow over the condenser allows R134a to work better.

 

[Trucker2k16]

Ok so your tell me that my brand new tube is bad? Ok explain that cause i put it in and pushed it to the pinch stop maybe im getting good air flow thru fins? The system is 8 oz of pag 150 it got that amount pulled vacuum for 1 hour and it held fir 3 days and dropped less than 1 pound then i charged the system with 36 oz of freon like it calls for so all that is wrong? It hasnt been over 86 degrees yet here in south Carolina. Liquid line sweats from the condensor to evaporator just like the low side and accumulator. 94-99 all engines crew cab ive done the same to a standard cab 4.3l and its been 3 years same pressures so where is the issue? Everything was ordered for c60 rpo code

 

[Trucker2k16]

In cold weather it's best to not mess with what you have. I assume it's blowing ice out the vents? The gauge readings were at 76F or 65F degrees out? Was the clutch cycling at all? To me it's either cold weather or the low pressure switch isn't kicking out in time. This temp is a "winter day" to me.

Can you elaborate on how you flushed the system and added oil? Note some new compressors come pre-filled with a full oil charge and some are dry.

Engine cooling... I recall reading the Duramax fan clutch comes on at a higher temp than the 6.5 clutches did. Do you mean the spin on fan clutch for a 6.5? Low temp fan clutch by Kennedy Diesel?



Looks like the fan clutch is moving a lot of air at idle. Less than 5 years old and a low temp fan clutch by Kennedy Diesel helps. At idle the Duramax fan wins over the 9 blade steel.

A electric aux pusher fan wired to come on with the compressor helps.

Insulate the "cold" line from the condenser orface tube to the firewall evaporator.

Insulate the accumulator - in fact some GM stuff has/had this foam overwrap from the factory. Typical: did it get ruined and tossed with accumulator replacement?

Bypass the heater core - some GM vehicles like, if I recall correctly, 1995 Yukon already had this valve from the factory.

Kick the idle up to 1200 RPM if you are waiting in a parking lot.

Coat the condenser with a Thermal Dispersant. Same with evaporator.

Not sure if a better more efficient compressor is available vs. the 1997 style compressor he has.

Move the hot oil coolers behind the condenser.

I know you don't like alternative flammable refrigerant. However it's night and day over this inefficient R134a gas esp. at higher outside temps. If you are in a 105 degree parking lot out in the dry dessert... The idling vehicle with water dripping out the AC drain isn't running 134a. (Late model vehicles appear to have R134a finally figured out so there is no need.) Short of this, again, more airflow over the condenser allows R134a to work better.

I didnt flush its all new and f kenndy diesel this is a hayden 2886 and acdelco Duramax fan and no at isle the compressor dont cycle it only cycles at 1600 rp the fan clutch kicks in after 10 mins of idling and it pulls air strong its the 50/50 coolant flow water pump noting on this 6.5l is stock

 

[Trucker2k16]

astockall acdelco compressors ive ever bought come dry i had sure i added 2 oz to it 2 oz to condenser 2 oz to evaporator and 2 oz in my inline injecter give a total 8 oz it did cycle while i was adding freon once it got 36 oz of freon it stopped and at 2000 rpm or 60 mph you can tell the clutch is cycling my first issues was p.o. jumped wires and i didnt realize it so i cut all that crap out and REPLACED WITH NEW EVEN ALL SENSORS!!!

 

[WarWagon]

I'd wait for a hot day and see how it performs.

If you are going to be attaching the gauges often I would get the brass plug Dorman sells for the high side and stop that leaky valve. It tends to leak if you attach gauge sets to it after the system has any run time on it. Heat and compressor wear debris cause it to leak.

 

[Will L.]

I agree, wait until heat starts making you unhappy and then check it out in mid 90 temp day.

On the orifice tube-
In Las Vegas Nv where 100f means it’s almost hot but not quite....
Had a fleet of over 300 gmt trucks that did over 100,000 miles per year- each truck-
So 10 months of the year someone in the shop was doing an a/c system.

We would evac and flush the system with new dryer and orifice every time. You replacing everything gets you to same place.
Then add oil and refer to measured amount. So far you did same we did.
When we ran it, if it did not hot proper specs- we sucked it all dry again, swapped out that new orifice for another new orifice. If humidity was 15% or higher that day we replaced it also. Put back in the oil and refer. Ran it again.

We had about 10% failure with brand new orifice bought directly from the dealership. We sent them back each with a bill for $50 shop labor time. Sometimes on inspection we could see the little square holes in the mesh were not a clean edge. Sometimes it looked like the pattern wasn’t equal. If we could have take. Phone pics then before install it would have been awesome to know what to look for. I wanted to build a test unit for flow/ pressure differential but boss said we we already into too much testing to take on another project. I tried talking to the gm engineers about it but basically so few customers complained it wasn’t worth it to them.

My hummer uses txv for front and rear or I would do the vov if it had regular orifice tube.
but my whole system is underbuilt so I am looking to do custom system in place anyways.

 

[THEFERMANATOR]

New compressors use pag46, you're going off old outdated literature. GM released a bulletin over 10 years ago about the change.

 

[Jaryd]

I'd wait for a hot day and see how it performs.

If you are going to be attaching the gauges often I would get the brass plug Dorman sells for the high side and stop that leaky valve. It tends to leak if you attach gauge sets to it after the system has any run time on it. Heat and compressor wear debris cause it to leak.

Where can I find this brass plug?