2006 Pilot EX A/C
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2006 Pilot EX A/C
2006 EX 4wd, 105,000 miles, no NAV or RES, all service up to date by Honda dealer since new. Second owner, bought used in 2015 with 28K on the clock.
Over the last three weeks or so, the A/C has slowly gotten weak and only blows warm air front and back; I suspect a leak or perhaps the TXV. After reading numerous other posts on the internet regarding A/C, here are my symptoms and what I've checked so far. No previous A/C work or repairs, system is still factory.
Compressor engages and stays on when A/C is on; both radiator and condenser fans run strong and shut off when A/C is off. The low pressure switch does not disengage the compressor, so I assume I have enough freon to function some. Blower motor works at all speeds; all modes between defrost/feet, etc, also work properly. After a time, condensate begins to drip under the car front and rear, leading me to believe evaporators are functioning but still no cold air. Low pressure line near the low pressure service port never gets cold. I checked the air mixture motor/linkage under the passenger dash and it appears to operate smoothly over the full range from hot to cold. The heater valve control on the firewall also appears to opening/closing with the air mix motor.
I ran the diagnostic for the HVAC circuits from the service manual at 21-78; no DTC's showed up. I also ran the diagnostic for the HVAC sensors from the SM at 21-82; all were in spec with the exception of the Front Air Mix Opening reading. With the temperature setting at max heat, it read 99%, indicating warmer air distribution. With the temperature set at max cool, it read 66%. Could this indicate a stuck air mix flap/door, preventing 100% of the air from being directed to the evaporator?
Next I hooked up a set of manifold gauges to high and low service ports. Temp was 76, humidity at 70. Static pressure was 69 psi on both.(On some of the R134 charts I looked at, I think my static pressure, based on atmospherics, should have been closer to 80 or so. Indicative of a low charge maybe?) Started car and let it reach operating temperature. Hit the A/C and low side dropped down to 8 psi, high side went up to 95 psi. Went through several manual on/off cycles, and the best I could get was 10 psi on the low and 105 psi on the high, which are both well below normal. Pressures did seem to equalize fairly quickly during the off cycles though (makes me think TXV not blocked). I performed only a cursory search for leaks, nothing extensive yet.
Would it be safe to add a bit of freon, without oil or other additives, to the system to get back to normal pressures and see if it holds? Any suggestions or something I overlooked?
Thanks in advance for your help.
FWIW, I'm a semi-expert when it comes to adding freon; my 2000 Blazer, which the Pilot replaced, was addicted to those little white cans for the last two summers of its miserable life...
Over the last three weeks or so, the A/C has slowly gotten weak and only blows warm air front and back; I suspect a leak or perhaps the TXV. After reading numerous other posts on the internet regarding A/C, here are my symptoms and what I've checked so far. No previous A/C work or repairs, system is still factory.
Compressor engages and stays on when A/C is on; both radiator and condenser fans run strong and shut off when A/C is off. The low pressure switch does not disengage the compressor, so I assume I have enough freon to function some. Blower motor works at all speeds; all modes between defrost/feet, etc, also work properly. After a time, condensate begins to drip under the car front and rear, leading me to believe evaporators are functioning but still no cold air. Low pressure line near the low pressure service port never gets cold. I checked the air mixture motor/linkage under the passenger dash and it appears to operate smoothly over the full range from hot to cold. The heater valve control on the firewall also appears to opening/closing with the air mix motor.
I ran the diagnostic for the HVAC circuits from the service manual at 21-78; no DTC's showed up. I also ran the diagnostic for the HVAC sensors from the SM at 21-82; all were in spec with the exception of the Front Air Mix Opening reading. With the temperature setting at max heat, it read 99%, indicating warmer air distribution. With the temperature set at max cool, it read 66%. Could this indicate a stuck air mix flap/door, preventing 100% of the air from being directed to the evaporator?
Next I hooked up a set of manifold gauges to high and low service ports. Temp was 76, humidity at 70. Static pressure was 69 psi on both.(On some of the R134 charts I looked at, I think my static pressure, based on atmospherics, should have been closer to 80 or so. Indicative of a low charge maybe?) Started car and let it reach operating temperature. Hit the A/C and low side dropped down to 8 psi, high side went up to 95 psi. Went through several manual on/off cycles, and the best I could get was 10 psi on the low and 105 psi on the high, which are both well below normal. Pressures did seem to equalize fairly quickly during the off cycles though (makes me think TXV not blocked). I performed only a cursory search for leaks, nothing extensive yet.
Would it be safe to add a bit of freon, without oil or other additives, to the system to get back to normal pressures and see if it holds? Any suggestions or something I overlooked?
Thanks in advance for your help.
FWIW, I'm a semi-expert when it comes to adding freon; my 2000 Blazer, which the Pilot replaced, was addicted to those little white cans for the last two summers of its miserable life...
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Re: 2006 Pilot EX A/C
"I also ran the diagnostic for the HVAC sensors from the SM at 21-82; all were in spec with the exception of the Front Air Mix Opening reading. With the temperature setting at max heat, it read 99%, indicating warmer air distribution. With the temperature set at max cool, it read 66%."
In reference to my above issues, can anyone out there run the same DX on a known working first gen A/C system to give me a baseline/comparison for the Front Air Mix Opening reading on max cold? Simple test, takes all of two minutes.
Again, thanks in advance for the help. Trying to get informed for probable DIY, prior to hitting dealership for quote in the thousands for complete new system.
Edited to add:
I also seem to recall reading that you will only get max pressure readings on the high side if you are transferring max heat into the system through the evaporator; i.e., removing heat from the interior of the car. This makes me think the air mix door may be stuck more towards the heat blend, and not directing enough air to the evaporator. I also borrowed an inspection camera/video scope from the local parts store and stuck it down the vent to try to see what was going on. I could see the air mix door moving, but due to poor video quality and my inability to manipulate the camera well, I couldn't tell if the door was fully opening/closing on the max cold temperature setting.
In reference to my above issues, can anyone out there run the same DX on a known working first gen A/C system to give me a baseline/comparison for the Front Air Mix Opening reading on max cold? Simple test, takes all of two minutes.
Again, thanks in advance for the help. Trying to get informed for probable DIY, prior to hitting dealership for quote in the thousands for complete new system.
Edited to add:
I also seem to recall reading that you will only get max pressure readings on the high side if you are transferring max heat into the system through the evaporator; i.e., removing heat from the interior of the car. This makes me think the air mix door may be stuck more towards the heat blend, and not directing enough air to the evaporator. I also borrowed an inspection camera/video scope from the local parts store and stuck it down the vent to try to see what was going on. I could see the air mix door moving, but due to poor video quality and my inability to manipulate the camera well, I couldn't tell if the door was fully opening/closing on the max cold temperature setting.
Last edited by Migra311; Jul 15, 2020 at 12:18 PM. Reason: Edited to add
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