Automotive Air Conditioning Information Forum

HI, Working on a friends 1997 Chevy C/K1500
VIN 1GCEK19M7VE249806
Model GMT-400 or CK10753
V8 5L, 1/2 Ton

No AC sticker in engine bay.

System was empty (conclusion since my hoses had about 50psi charge in them and when connected to system, system showed 12 psi which could have come from hose. Could have a more conclusive result if I emptied my hoses, bummer)

Friend said mechanic moved AC compressor out of the way for some other work but said did not loosen any connections. AC worked (not great) before mechanic work.

1) what is the R134a capacity for this truck?

2) Nitrogen pressure test degradation is below.
Thoughts on this? Acceptable?
Did not hear any leaking.

starting form 362psi
-9 psi first 12 min 353 psi
-32 psi (-41 psi total) over next 3hr 12min (3hr 24min cumulative) 321 psi
-44 psi (-84 psi total) over next 8hr 35min (11hr 59min cumulative) 277 psi

3) will vacuum now and will report vacuum results.

Thanks

PSI / Date / PSI change / Time change from last reading / Notes
362 / 2024-7-17 5:58 PM / / /
353 / 2024-7-17 6:10 PM / -9 / 0:12:00 /
321 / 2024-7-17 9:22 PM / -32 / 3:12:00 /
277 / 2024-7-18 5:57 AM / -44 / 8:35:00 / Overnight with tempo drop from 90F to 65F

andrew vanis wrote: ↑Thu Jul 18, 2024 5:38 am 3) will vacuum now and will report vacuum results.

vacuumed down to 310 microns. viewtopic.php?p=29802#p29802

about 20 min later it was at 370. will report again as more time passes.

Refrigerant-134a
Pickup Models .................... 0.91 kg (2.0 lb)
Crew Cab Models .................... 1.02 kg (2.25 lb)


Polyalkaline Glycol (PAG) Refrigerant Oil
Air Conditioning System .................... 240 ml (8 fl oz)

Tim wrote: ↑Thu Jul 18, 2024 7:53 am Refrigerant-134a
Pickup Models .................... 0.91 kg (2.0 lb)
Crew Cab Models .................... 1.02 kg (2.25 lb)


Polyalkaline Glycol (PAG) Refrigerant Oil
Air Conditioning System .................... 240 ml (8 fl oz)

Thanks Tim.

How does one determine pickup vs crew cab?

Internet shows 3 diff combinations - link to different body styles removed removed per "I don't think we need Goggle links on the site." comment below....so to see different combinations of cabs

1 - front doors only, front seating only
2 - front doors and 1/2 doors, front seating and cramped rear seating - This is the type I'm working on
3 - 2 full doors, front and full rear seating.

I don't think we need Goggle links on the site.

Anything larger than a single door/cab.

Thanks Tim

the rest Self-deleted for posing a provocative response....Wish I didn't get so triggered by Tim. He can be so helpful.

andrew vanis wrote: ↑Thu Jul 18, 2024 8:49 am Thanks Tim

the rest Self-deleted for posing a provocative response....Wish I didn't get so triggered by Tim. He can be so helpful.

There's no reason to be triggered. You know I don't care for unnecessary links on the site. Maybe other sites allow it, but this site has been that way for the entire time I've had it. I am not singling you out by any means. Heck, I did not even edit your post.

Tim wrote: ↑Thu Jul 18, 2024 5:21 pm

andrew vanis wrote: ↑Thu Jul 18, 2024 8:49 am Thanks Tim

the rest Self-deleted for posing a provocative response....Wish I didn't get so triggered by Tim. He can be so helpful.

There's no reason to be triggered. You know I don't care for unnecessary links on the site. Maybe other sites allow it, but this site has been that way for the entire time I've had it. I am not singling you out by any means. Heck, I did not even edit your post.

Off topic alert -

IDK Tim, it's for me to work on. I'm guessing it's residual from the rough start between us when I started on here. What's triggering for one, another may not see anything triggering about it since they see it differently - ultimately it is impossible for any two persons to have the exactly same view.

I also do not like unnecessary links and strive to write posts in a way that is efficient and helpful for the reader....our history indicates our views differ on what's unnecessary, efficient, and/or helpful in a post .

And ultimately this is the decider, it's your playground so you get to say how it goes around here so I'm working on complying with expectations beyond published rules as I learn those expectations over time...I'm doing the best I can

Now back to Auto AC stuff....

Tim wrote: ↑Thu Jul 18, 2024 7:53 am Refrigerant-134a
Pickup Models .................... 0.91 kg (2.0 lb)
Crew Cab Models .................... 1.02 kg (2.25 lb)


Polyalkaline Glycol (PAG) Refrigerant Oil
Air Conditioning System .................... 240 ml (8 fl oz)

Wrap up summary-

Best performance ended up being at 28oz (1.75lbs - 77%i of the 2.25lbs target). Center vent output was 38F with all doors open on a 105F day. I'm guessing excess oil in the system is causing best cooling at this lower refrigerant quantity since it may be reaching ideal total system capacity just with a higher oil-to-refrigerant ratio.

Here's what I wrote up about this on another post:

friends truck which was messed with before me including adding oil. I didn't have time or interest then to flush it so while filling towards specified capacity I noticed Max performance was at about 75% of specified capacity and with more refrigerant performance went down (it was cooling worse/went temps started rising). Will not know what really is causing that and I'm guessing too much oil. We were getting down to 38F from the center vents with all doors open on a 105F day so we left it alone at that point.

Andrew, you might have read my recent post on the Excursion. I'll recap real quick. I reached out to our in-house tech guy. He said, in some cases, especially Ford. They (are) reducing the charge level by about 10%. But remember, a lower charge means less refrigerant to carry oil through the system. So always try to balance this for reliability.