Amateur owner questions.
Inadequate cooling in old 2001 Toyota Sienna. Manual AC. Front and rear AC with separate expansion valves and evaporators.
Bought 1 yr ago. Subjectively good AC performance in 85 degree weather 1 yr ago. Barely adequate AC 3 months ago in 100 deg weather. July 2018 inadequate cooling in 100 deg weather. Barely cool in 75 deg weather.
Checked pressures 2 days ago.
Ambient temp about 90 deg F.
Humidity not known.
AC vent temp measured using digital meat thermometer in degrees F. Air flow to vents normal at dash and rear AC. Temps at rear AC not better than dash.
Temp of upper and lower condenser lines measured with IR thermometer in degrees F. Do not know if this is accurate. Do not have AC temp probe.
Used HFT manifold gauge.
Compressor does not cycle when testing. Clutch engages when AC is on and does not disengage until manually turned off when tested at 75-95 deg F.
Has hot water valve. Visually checked valve under hood. Valve moves from hot to cold position when hot-cold knob is turned to cold.
Hot-cold knob at dash to hot makes vent air hot. Knob to cold makes air colder. Do not know if water valve actually shuts hot water off. Do not know how to test doors of air ducts but there is a thump when moving knob from full cold-hot-cold.
R134 Pressures:
Engine off
LOW 80 psi
HIGH 80 psi
AC vent temp 94F
Engine on AC on
Engine idle 700 rpm
LOW 30 psi
HIGH 135
AC vent temp 68
Engine 1500 rpm AC on
LOW 25
HIGH 145
AC vent temp 68
---------------------
Added R134 without sealant for 30 seconds. Did not weigh can. Probably less than half 12 oz can dispensed.
Recheck pressures.
Engine 1500 rpm AC on
LOW 35 psi
HIGH 190
AC vent temp 76F. Yes, vent air felt warmer.
Misting condenser did not improve vent temp but did not recheck pressures.
-------------
2 days later. Ambient temp 77 deg rel humidity 65%.
Checked temp of condenser upper and lower lines with IR thermometer. Unknown if this is accurate. Did not recheck pressures.
Engine at Idle 700rpm.
Upper 137deg F -145 deg F at first.
later
Upper 137-140
Lower 117-122 at first
later
Lower 130
The difference seems low to me if measurements are reasonably accurate. Difference is less if AC is run longer.
---------
I felt refrigerant was slightly low at first but adding some did not help performance.
Vent air seems to get hotter if I test for 30 minutes or longer. Driving the car to get airflow helps minimally.
Seems compresor is making pressure and refrigerant level is enough to get better cooling than I now have.
Temp difference across condenser seems low if readings are reasonably accurate. Do not know how to check for restriction. But r134 pressures are not high so maybe is not restriction. Condenser does not appear dirtier than my other cars but have not tried to clean it beyond hosing it to mist it.
I do not know how to check hot water valve or evaporator.
I do not know how to check expansion valves or evaporators. Has front and rear expansion valves and front and rear evaporators according to parts web site. Both front and rear vent air are equally hot so not so likely to be evaporator or expansion valves problem as the front and rear are separate.
In the end, maybe condenser is the problem.
What to do next?
Thanks.
Inadequate cooling in old 2001 Toyota Sienna. Manual AC. Front and rear AC with separate expansion valves and evaporators.
Bought 1 yr ago. Subjectively good AC performance in 85 degree weather 1 yr ago. Barely adequate AC 3 months ago in 100 deg weather. July 2018 inadequate cooling in 100 deg weather. Barely cool in 75 deg weather.
Checked pressures 2 days ago.
Ambient temp about 90 deg F.
Humidity not known.
AC vent temp measured using digital meat thermometer in degrees F. Air flow to vents normal at dash and rear AC. Temps at rear AC not better than dash.
Temp of upper and lower condenser lines measured with IR thermometer in degrees F. Do not know if this is accurate. Do not have AC temp probe.
Used HFT manifold gauge.
Compressor does not cycle when testing. Clutch engages when AC is on and does not disengage until manually turned off when tested at 75-95 deg F.
Has hot water valve. Visually checked valve under hood. Valve moves from hot to cold position when hot-cold knob is turned to cold.
Hot-cold knob at dash to hot makes vent air hot. Knob to cold makes air colder. Do not know if water valve actually shuts hot water off. Do not know how to test doors of air ducts but there is a thump when moving knob from full cold-hot-cold.
R134 Pressures:
Engine off
LOW 80 psi
HIGH 80 psi
AC vent temp 94F
Engine on AC on
Engine idle 700 rpm
LOW 30 psi
HIGH 135
AC vent temp 68
Engine 1500 rpm AC on
LOW 25
HIGH 145
AC vent temp 68
---------------------
Added R134 without sealant for 30 seconds. Did not weigh can. Probably less than half 12 oz can dispensed.
Recheck pressures.
Engine 1500 rpm AC on
LOW 35 psi
HIGH 190
AC vent temp 76F. Yes, vent air felt warmer.
Misting condenser did not improve vent temp but did not recheck pressures.
-------------
2 days later. Ambient temp 77 deg rel humidity 65%.
Checked temp of condenser upper and lower lines with IR thermometer. Unknown if this is accurate. Did not recheck pressures.
Engine at Idle 700rpm.
Upper 137deg F -145 deg F at first.
later
Upper 137-140
Lower 117-122 at first
later
Lower 130
The difference seems low to me if measurements are reasonably accurate. Difference is less if AC is run longer.
---------
I felt refrigerant was slightly low at first but adding some did not help performance.
Vent air seems to get hotter if I test for 30 minutes or longer. Driving the car to get airflow helps minimally.
Seems compresor is making pressure and refrigerant level is enough to get better cooling than I now have.
Temp difference across condenser seems low if readings are reasonably accurate. Do not know how to check for restriction. But r134 pressures are not high so maybe is not restriction. Condenser does not appear dirtier than my other cars but have not tried to clean it beyond hosing it to mist it.
I do not know how to check hot water valve or evaporator.
I do not know how to check expansion valves or evaporators. Has front and rear expansion valves and front and rear evaporators according to parts web site. Both front and rear vent air are equally hot so not so likely to be evaporator or expansion valves problem as the front and rear are separate.
In the end, maybe condenser is the problem.
What to do next?
Thanks.
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