Few A/C questions.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

meir

OBS Enthusiast
Joined
Sep 19, 2017
Messages
56
Reaction score
9
Location
coral springs FL
Hi guys.

I’m in the process of replacing the A/C condenser on my truck, along with a new dryer, orifice tube, and O-Rings on all connection.

Didn’t give it much thought, but during research I understood my truck (89 K1500) is running R12 refrigerant. By Looking at the system it looks like it was already converted to 134a at some point.

Not knowing if to correct oil was use, and the fact that the compressor was not changed (R4 compressor), I will go with the Ester oil, that is compatible with both R12 and 134a.

https://shop.advanceautoparts.com/p...e-32-8-fl-oz-py-7/7060394-P?searchTerm=ac+oil

it is also at the same viscosity needed for the R4 compressor.

From reading about the subject, it sounds like the 134a is not as efficient as the R12, and requires a new compressor and a larger condenser. At this point, I will stick with the compressor I have, and the new condenser is already installed.

This is the condenser I got:

https://www.amazon.com/gp/product/B000CKOW02/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

I plan on adding an electric fan to it, that will circulate with the compressor.

The questions I have are as follow.

1. Where is the orifice tube located on the 89 trucks?

I did not see it on the line going into the evaporator.

2. What’s your take on this Freon as an alternative to the 134a?

https://www.amazon.com/Cans-REDTEK-...rd_wg=7EzIG&psc=1&refRID=J95D5FG5DZKK600WKYGA
3. according to shop manual, i will need to add 5oz of oil.
do i just pour it into the dryer? i assume if i pull vacuum, it will suck the oil out.
am i missing something?

any other input would be greatly appreciated.

Thanks in advance.

Meir.
 
Last edited:

454Suburban

Newbie
Joined
Mar 19, 2018
Messages
6
Reaction score
1
Location
richmond, VA
R134a requires PAG oil, I used PAG 150 on my 92 pickup conversion. As far as the condenser, you need a parallel flow type. The orifice tube for your 89 should be in the lower tube on your evaporator, thats where my 91 suburban is. For my 92, it called for 8 oz. oil. 4 in the suction side of compressor, 4 in the accumulator. Turn compressor over by hand, if possible to pump oil thru it.
 

meir

OBS Enthusiast
Joined
Sep 19, 2017
Messages
56
Reaction score
9
Location
coral springs FL
R134a requires PAG oil, I used PAG 150 on my 92 pickup conversion. As far as the condenser, you need a parallel flow type. The orifice tube for your 89 should be in the lower tube on your evaporator, thats where my 91 suburban is. For my 92, it called for 8 oz. oil. 4 in the suction side of compressor, 4 in the accumulator. Turn compressor over by hand, if possible to pump oil thru it.
Thanks.
BTW this the ester oil description from the website.

  • “Medium viscosity ester oil for all R-134a systems; ISO 100 viscosity, SUS at 100°
  • ICE32 Lubricant Enhancer: advanced chemistry to help extend compressor life and improve cooling capacity
  • Formulated for retrofitting R-12 systems to R-134a
  • Meets OEM specifications “
On my truck the manual say that I he total oil capacity is 6oz.
If replacing accumulator add the Sam amount that came out, or 3 oz.
when replacing evaporator add another 2oz.
 

studigggs

I'm Awesome
Joined
Feb 19, 2018
Messages
257
Reaction score
317
Location
CA
Im running the stock tube-and-fin condenser in my '90 with r134. ice cold in 100+ temps. Only mod was to a 11 blade fan and heavy duty fan clutch. If you switch to a parallel flow condenser you wont be able to charge the system by weight.

And you've probably figured this out, but you got the wrong condenser you'll need the Spectra 4295 if you are sticking with parallel flow.
 
Last edited:

L31MaxExpress

I'm Awesome
Joined
Apr 21, 2018
Messages
5,890
Reaction score
7,540
Location
DFW, TX
Im running the stock tube-and-fin condenser in my '90 with r134. ice cold in 100+ temps. Only mod was to a 11 blade fan and heavy duty fan clutch. If you switch to a parallel flow condenser you wont be able to charge the system by weight.

And you've probably figured this out, but you got the wrong condenser you'll need the Spectra 4295 if you are sticking with parallel flow.

Just curious what the vent temps are?

I never have had a vehicle with r134a that I felt was ice cold in more than 90°F ambients. Even late model cars with TXV systems and electric fans. In fact most of them fail to even be able to get down to 50°F at idle.
 

studigggs

I'm Awesome
Joined
Feb 19, 2018
Messages
257
Reaction score
317
Location
CA
I
Just curious what the vent temps are?

I never have had a vehicle with r134a that I felt was ice cold in more than 90°F ambients. Even late model cars with TXV systems and electric fans. In fact most of them fail to even be able to get down to 50°F at idle.

I'll have to check tomorrow. in the 110s this week so will be a good test.
 

L31MaxExpress

I'm Awesome
Joined
Apr 21, 2018
Messages
5,890
Reaction score
7,540
Location
DFW, TX
111 today. 58 deg around town between 10-35 mph. At idle it would climb to 64

Case in point, 65°F discharge temp to me would be miserable, IMO.

Ambient was 107°F driving the 2007 G35 today. R152a and stock as it rolled down the factory 160K mile system. 44°F at idle in bumper to bumper with high fan speed and recirculate. Got down to 36°F after 7 miles at 80 mph.

R134a is terrible as a refrigerant, IMHO.
 
Joined
Nov 25, 2017
Messages
41
Reaction score
6
Location
Lubbock
I would pull and drain the unit. A vaccum is not going to pull the oil from the system. I would also use dry nitrogen to blow thru the evap that you plan to reuse. As to the debate on refrigerants. Im not a fan of 134a but with the avalibility of r12 as scarce as it is compared to r134a i would make the switch. Remember we are acheiving high temp refrigeration in this type of system. There is no defrost as in medium and low temp. Your pressusres and tempratures are relative to the enviroment the system is in. In a very humid climate a 33 or 34* discharge temp at the vent puts your evaporator coil well below freezing with more of a chance if icing. Ive driven both types of units r12 and r134a. A properly charged unit in either will get plenty cold. If you plan to use 134a i would go with a pag oil. It will be better for oil return which is the reason it is used in this application. If you use r12 i would stick with what the factory put in it originally. There is a reason they dont use the old style oil in newer vehicles. Likely you could also convert to r290 or propane. Id have to refer to a pt chart to verify but it also is making a return tonthe market in automobiles

Sent from my SM-G955U using Tapatalk
 

meir

OBS Enthusiast
Joined
Sep 19, 2017
Messages
56
Reaction score
9
Location
coral springs FL
Hello guys.
Thank you very much for all the inputs.
I decided to go with these products.
The refrigerant
https://www.amazon.com/Cans-REDTEK-...rd_wg=7EzIG&psc=1&refRID=J95D5FG5DZKK600WKYGA
And the oil
https://www.amazon.com/RED-TEK-OilC...rd_wg=Bj316&psc=1&refRID=QDSZC2VY2P1DC5N99DQP

A bit more pricey then than the 134a, but allegedly more efficient, and competible with bothe r12 and 134a, and the oil is compatible with mineral and pag.
The o rings I’m using are compatible with bothe as well, and I added an electric fan in front of the condenser. Still need to decide how to hook it up. Either always on when ac is one, or alternating with the compressor.
I will update with results once completed.

As a side note, the Red-Tek website has a conversion chart that calles for 1 to 3 reletion between the Red-Tek to r12. So I will need 2 an a half cans.
 
Last edited:
Top