Need some A/C help - ZR-1 Net Registry Forums

Tripler · 08-07-2020

Did you also pressure test the system with nitrogen for a 1/2 hr or so ? And flush the system with nitrogen before adding 134a ? There could still be moisture in the system even tho you put a vacuum on the system to pull the moisture out . This is what I did on residential .
Oh and also , when assembling connections , did you use a bit of refrigerant oil or vacuum pump oil to lube the connections ? That's important for a good seal because of aluminum binding against itself , even the brass connections will need lube .

Sent from my SM-A205W using Tapatalk

Ccmano · 08-07-2020

Quote:

Originally Posted by Tripler

Did you also pressure test the system with nitrogen for a 1/2 hr or so ? And flush the system with nitrogen before adding 134a ? There could still be moisture in the system even tho you put a vacuum on the system to pull the moisture out . This is what I did on residential .
Oh and also , when assembling connections , did you use a bit of refrigerant oil or vacuum pump oil to lube the connections ? That's important for a good seal because of aluminum binding against itself , even the brass connections will need lube .

Sent from my SM-A205W using Tapatalk

Thanks for your input. I don't have the equipment to do a nitrogen pressure test and flush. Thanks for the tips about lubing the connections. From the looks of things I will be taking things apart again and starting fresh. As noted on my previous post I suspect there is an issue with the high side connection to the gauges.
H

Marc Haibeck · 08-09-2020

Hi Hans,

Both of the cooling fans should turn on within 30 seconds of turning on the compressor. There is a fan switch on the high pressure line. It's the smaller of the two switches by the dipstick. The switch opens when the pressure goes to 240 psi. As a test, if the connector is removed the fans will turn on.

At 55 degrees at the center duct the performance might be normal. Generally the system should cool to the ambient temperature - 35 degrees. The '90 and '91 service manuals have a performance rating chart. Look up the ambient temperature and humidity on the chart.

Ccmano · 08-09-2020

Update, as suspected the high side quick coupler does not engage the Schrader valve because once the adapter is installed the Schrader valve sits too deep. I found a work around and now have both high and low pressures. High side is ~260psi and low side is ~32psi with a center vent temp ~45degrees on an 90degree ambient day. So all of that looks within spec. The only issue that remains is that the pressures do not equalize, not even overnight. High side drops the ~110psi and low to ~25psi.

What remains a major issue is the unabated climb in coolant temp with the AC on at idle. When driven without stopping the temps stay normal. The temps rise after a few minutes of driving in stop and go traffic so that the coolant temps are already over 230 and rising. Both fans come on when the AC is turned on per spec. Once the AC is off temps return to normal no matter what the ambient temps. Both the radiator and the condenser have now been replaced. Both needed it as they were badly clogged with sand a grit. The accumulator/drier and orifice tube have been replaced as well.

So I'm thinking the lack of equalization and the high temps are related, probably an obstruction of some sort.
Thoughts?
H

08-07-2020	#1
Tripler Join Date: Apr 2013 Location: Toronto Posts: 716	Re: Need some A/C help Did you also pressure test the system with nitrogen for a 1/2 hr or so ? And flush the system with nitrogen before adding 134a ? There could still be moisture in the system even tho you put a vacuum on the system to pull the moisture out . This is what I did on residential . Oh and also , when assembling connections , did you use a bit of refrigerant oil or vacuum pump oil to lube the connections ? That's important for a good seal because of aluminum binding against itself , even the brass connections will need lube . Sent from my SM-A205W using Tapatalk Last edited by Tripler; 08-07-2020 at 06:59 PM.

08-09-2020	#3
Marc Haibeck Join Date: May 2007 Location: Addison IL Posts: 241	Re: Need some A/C help Hi Hans, Both of the cooling fans should turn on within 30 seconds of turning on the compressor. There is a fan switch on the high pressure line. It's the smaller of the two switches by the dipstick. The switch opens when the pressure goes to 240 psi. As a test, if the connector is removed the fans will turn on. At 55 degrees at the center duct the performance might be normal. Generally the system should cool to the ambient temperature - 35 degrees. The '90 and '91 service manuals have a performance rating chart. Look up the ambient temperature and humidity on the chart.

08-09-2020	#4
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Need some A/C help Update, as suspected the high side quick coupler does not engage the Schrader valve because once the adapter is installed the Schrader valve sits too deep. I found a work around and now have both high and low pressures. High side is ~260psi and low side is ~32psi with a center vent temp ~45degrees on an 90degree ambient day. So all of that looks within spec. The only issue that remains is that the pressures do not equalize, not even overnight. High side drops the ~110psi and low to ~25psi. What remains a major issue is the unabated climb in coolant temp with the AC on at idle. When driven without stopping the temps stay normal. The temps rise after a few minutes of driving in stop and go traffic so that the coolant temps are already over 230 and rising. Both fans come on when the AC is turned on per spec. Once the AC is off temps return to normal no matter what the ambient temps. Both the radiator and the condenser have now been replaced. Both needed it as they were badly clogged with sand a grit. The accumulator/drier and orifice tube have been replaced as well. So I'm thinking the lack of equalization and the high temps are related, probably an obstruction of some sort. Thoughts? H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.