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Low side OK, High side low

torque395 on Tue June 30, 2009 1:34 PM User is offline

Year: 1996
Make: Chevrolet
Model: Suburban
Engine Size: 6.5L
Refrigerant Type: R-134a
Ambient Temp: 85
Pressure Low: 35
Pressure High: 125
Country of Origin: United States

Sorry about the double post, when i started to type in the year, firefox knew what i wanted to type and and showed it in the drop down box, then when I hit enter to select it, it instead posted the message. What a piece of ****!! lol

Anyways. Ive posted before but my other post seems to be dead.

Air flow is likely an issue with my truck, but i don't think its the ONLY issue. With no water on the condenser, engine idling, the pressures are about 55psi on the lowside and 250psi on the high side. Both of those are kind of high. Now, WITH water on the condenser, pressures drop to 35 low, 125 high. 35 is great. 125 is low.

Whats up with that?

The system was known to leak, but appeared to be at the service ports, so a new high side port was installed, as was a new valve core in the low side.

Vent temps generally hit 60 pretty easy while driving but at idle they can run 70-80 depending on outside temp. They have seen 45-50 degrees but its difficult to get that out of it. You have to be on the highway (engine running about 2000rpm at this point) and have to be there for a while.

At any rate, cooling is better while driving than while idle. I know i need to clean the radiator and condenser (fan clutch seems fine you can turn it by hand but it wont freewheel. It has enough resistance that when you take your hand off of it, it stops turning. Also at 210 degrees you can hear it ROAR). But, with water on the condenser which for testing purposes makes up for the inadequate airflow, the high side pressure is too low. That is my concern. It really didnt seem to help the vent temp too much either. The only thing i could think of is a weak compressor which was originally my concern a while back.

1996 Chevy Suburban 2500 4x2 6.5L Turbo

Cussboy on Tue June 30, 2009 2:30 PM User is offline

125 psi for high side appears low on refrigerant.

torque395 on Tue June 30, 2009 6:56 PM User is offline

In that case, isnt 35 psi low-side pressure kind of on the high side for a system that is low on refrigerant?

1996 Chevy Suburban 2500 4x2 6.5L Turbo

Chick on Tue June 30, 2009 7:30 PM User is offlineView users profile

Unless you only drive in the rain, the "water misting" of the condenser is to check for airflow problems, you spray a "mist" on the condenser, and if the high side drops like a stone, possible air flow problems.. You checked that and the pressures dropped, but how fast/ I would check the seams of the compressor for possible leak spots...

Email: Chick


Freedoms just another word for nothing left to lose

torque395 on Tue June 30, 2009 8:38 PM User is offline

The pressures did drop, by 50%, like a rock. And yes i know it was just for a test, but those are the readings i should get with proper airflow. I am just waiting for a time when my truck is cold from sitting all night to start taking it apart to clean out the radiator and condenser. I haven't noticed any oily spots indicating a leak since i changed the service ports but I will look over the rest of the system.

1996 Chevy Suburban 2500 4x2 6.5L Turbo

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