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2006 Saturn Vue cooling at idle
Posted: Thu Jul 18, 2019 5:28 am
by satvue
2006 Saturn Vue 3.5 V6. Over the last 2 years the A/C would cool fine going down the road and immediately stop cooling at a stop. I replaced the compressor, condenser, drier and evap. Pulled a vacuum, no leaks charged with 28 oz. At idle vent temp is 70 F, low side is 57 high side is 180 with outside temp at 87. At 3K rpm vent temp drops to 57, low side 38, high side 210ish. I've checked relays, fuses, wires, fans and I got nothing. It's been in 2 different shops that were no help. I've had this thing apart 3 times over the last 2 months trying to fix it. What am I missing?
Re: 2006 Saturn Vue cooling at idle
Posted: Thu Jul 18, 2019 5:41 am
by Cusser
satvue wrote:Over the last 2 years the A/C would cool fine going down the road and immediately stop cooling at a stop. What am I missing?
To me, this seems to align with a failure to cool the condenser properly; so I'd make sure all the fans are operational whenever the AC is running. Also make sure that the fan air flow is from front of vehicle to rear, so through the condenser.
Another thing to do when the cooling is poor would be to immediately pull over and see if the AC compressor clutch is still engaged/spinning (the center of the compressor).
Re: 2006 Saturn Vue cooling at idle
Posted: Thu Jul 18, 2019 5:54 am
by satvue
Cusser wrote:satvue wrote:Over the last 2 years the A/C would cool fine going down the road and immediately stop cooling at a stop. What am I missing?
To me, this seems to align with a failure to cool the condenser properly; so I'd make sure all the fans are operational whenever the AC is running. Also make sure that the fan air flow is from front of vehicle to rear, so through the condenser.
Another thing to do when the cooling is poor would be to immediately pull over and see if the AC compressor clutch is still engaged/spinning (the center of the compressor).
The fans are located behind the radiator, not sure they can be moved to the front? Good point on the clutch, i have checked it over and over and it is engaged.
Re: 2006 Saturn Vue cooling at idle
Posted: Thu Jul 18, 2019 8:04 am
by satvue
I meant to ask in my original post, the radiator fans are running but always at a the same speed (no high or low). Any chance there's a resistor that has went bad not kicking the fans to high? I"m grasping at straws...
Re: 2006 Saturn Vue cooling at idle
Posted: Thu Jul 18, 2019 9:09 am
by bohica2xo
The fans should change speed depending on cooling load. This is normally decided by refrigerant pressure & ambient temperature.
A few questions:
Have you owned this car since it was new?
When was the last time you changed the cabin air filter?
Are there some clicking or popping sounds from the dash area when you first start the car?
You can check the condenser airflow by spraying some water on the condenser and watching your gauges / vent temperature. Usually around 1500 engine rpm this test is the most telling with that scroll compressor.
Your high side of 210psi @ 87f ambient looks fairly normal.
Re: 2006 Saturn Vue cooling at idle
Posted: Thu Jul 18, 2019 9:18 am
by satvue
bohica2xo wrote:The fans should change speed depending on cooling load. This is normally decided by refrigerant pressure & ambient temperature.
A few questions:
Have you owned this car since it was new? I've owned it since 2009
When was the last time you changed the cabin air filter? I honestly didn't realize it had a cabin filter, I will be replacing that today. (Thanks)
Are there some clicking or popping sounds from the dash area when you first start the car? No popping or clicking
You can check the condenser airflow by spraying some water on the condenser and watching your gauges / vent temperature. Usually around 1500 engine rpm this test is the most telling with that scroll compressor.
Your high side of 210psi @ 87f ambient looks fairly normal.
Re: 2006 Saturn Vue cooling at idle
Posted: Fri Jul 19, 2019 8:33 am
by bohica2xo
Many times someone has a vehicle for a few months, and has no history on it.
Since you have owned it for a long time, you know that this is a new issue. You replaced the entire system - was there a reason to go after the Evaporator?
Your radiator fans would be the logical place to start. I believe the control is solid state, with both fans running when the A/C is on, then ramping up speed based on high side pressure.
A one month subscription to the full factory service manual is available from Mitchell for about 20 bucks. This includes a complete wiring diagram for the car as well as all of the troubleshooting flow charts. The FSM will detail your cooling fan circuit & control
If it cools at idle with a bit of water sprayed on the condenser, while holding 1500 engine rpm - you need to look at the fans. We have seen fan motors that were just plain worn out here in the desert.
The clicking is the GM issue with the stepper motors that move the blend doors in the evaporator case. If yours are still working then great.
When you pull the cabin filter check the cavity behind it. A little shop vac work may be in order...
Re: 2006 Saturn Vue cooling at idle
Posted: Fri Jul 19, 2019 11:50 am
by satvue
I'm almost positive it fan related, they both run but always on what I would consider low. If i pull the relay for the low speed fan they stop, but the high speed relay does nothing. How would I adjust the high pressure side to kick the fans into high? Appreciate the help.
Re: 2006 Saturn Vue cooling at idle
Posted: Fri Jul 19, 2019 2:32 pm
by bohica2xo
The high side is a 3 wire pressure transducer that feeds high side pressure information to the PCM. The PCM makes the fan speed decision. It is not a simple switch, and is not adjustable. It is a 5 volt input, with a 1 to 4.5v output.
The sensor could be bad, or the wiring to the sensor. The high side relay could also be bad - have you swapped it with a known good part? Checked the fuses?
Re: 2006 Saturn Vue cooling at idle
Posted: Fri Jul 19, 2019 7:27 pm
by satvue
bohica2xo wrote:The high side is a 3 wire pressure transducer that feeds high side pressure information to the PCM. The PCM makes the fan speed decision. It is not a simple switch, and is not adjustable. It is a 5 volt input, with a 1 to 4.5v output.
The sensor could be bad, or the wiring to the sensor. The high side relay could also be bad - have you swapped it with a known good part? Checked the fuses?
Where can I find that sensor (the one that's attached to the compressor)? I've swapped around the relays and fuses in the fuse box under the hood they all check out.