2003 toyota sequoia, a/c low pressure to high

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AUTOWORK9207
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2003 toyota sequoia, a/c low pressure to high

Postby AUTOWORK9207 » Thu Jul 26, 2018 1:43 pm

i have a 2003 toyota sequoia presenting with ac not blowing cold. pressures came in with low side 55 and high side 225. also found compressor to have a little leak. went ahead and changed compressor, and both expansion valves. recharged system and pressure was low was 60 and high still 225. sprayed water on condenser and pressures did not change. was worried about moisture and or air in drier so changed drier as well. still same result. did notice a slight occasional flux in pressure, so changed compressor again. (fyi not first time company got parts from sent bad parts. this is a system being replaced under warranty because it didn't last a year) no change in pressure after another compressor but the flux went away. checked temp of line to expansion valves, there was slight temp difference so replaced those again as well. once recharged again low pressure still at 60 and high at 225. did verify multiple times putting correct amount of freon, even went as far as put a little less to see if any change, just in case the spec was off, but no change. can anyone help shed some insight that i may be missing
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bohica2xo
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby bohica2xo » Sun Jul 29, 2018 2:40 pm

Moved this post to the proper forum.

What was your ambient temperature at the time those pressures were recorded?
AUTOWORK9207
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby AUTOWORK9207 » Mon Jul 30, 2018 8:16 am

THE AMBIENT TEMP WAS ABOUT 90 DEGREES
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bohica2xo
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby bohica2xo » Mon Jul 30, 2018 8:26 am

Are you sure you have 39 ounces of 134a in it? Undercharging is not the answer to this problem.

Do a full load test. Doors open both evaporator fans on highest speed. Run the engine at 2000 RPM for one minute to stabilize the system, and record the pressures while still at 2000 RPM.

Post the pressures, ambient temperature & vent temperature.
AUTOWORK9207
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby AUTOWORK9207 » Mon Jul 30, 2018 9:15 am

LOW PRESSURE 55PSI, HIGH PRESSURE 225PSI, VENT TEMP 62 DEGREES, AMBIENT TEMP 83 DEGREES. FULL CHARGE. BOTH EVAPORATOR FANS ON
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bohica2xo
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby bohica2xo » Mon Jul 30, 2018 1:35 pm

Nothing looks terribly wrong with those numbers under full load for a vehicle that size.

2.7:1 P/T ratio, condenser fans are rejecting heat. 21f drop from ambient in a worst case test.


What is the relative humidity at your location?
AUTOWORK9207
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby AUTOWORK9207 » Mon Jul 30, 2018 4:48 pm

HUMIDITY TODAY IS 19% BUT USUALLY WE ARE PRETTY DRY HERE, AS WE ARE IN THE HIGH DESERT.
THE PRESSURE SPECs SHOW THAT OUR PRESSURES ARE WAY OFF. THE SPEC FOR THIS VEHICLE WITH FRONT AND REAR AIR, LOW RANGE 36-50PSI AND HIGH 270-299PSI. SO WITH THAT IN MIND OUR LOW SIDE IS HIGH, AND OUR HIGH SIDE IS TO LOW. AND 67 DEGREES IS COOLEST IT WILL GO AND THAT'S IN BAY.
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bohica2xo
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby bohica2xo » Mon Jul 30, 2018 5:09 pm

Well, that leaves an undercharge, or a bad compressor

Rear A/C vehicles hold an additional 11 ounces of refrigerant, 39 ounces is the dual evaporator charge.

The alleged "spec" od 299 psi @ 83f would be way out of line for most vehicles. It would be bouncing off the HPCO in warmer places.


Block the condenser airflow & watch the high side. Perphaps the compressor is just not capable of full capacity.
AUTOWORK9207
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby AUTOWORK9207 » Tue Jul 31, 2018 9:32 am

Blocked air flow and high pressure only went to 300psi at 2500rpm
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Re: 2003 toyota sequoia, a/c low pressure to high

Postby bohica2xo » Tue Jul 31, 2018 10:30 am

Compressor lacks capacity.

Is that compressor another reman for the same source? Is it slathered in black paint?

Try another compressor vendor. If they send the wrong parts all the time anyway...

Denso was the OEM compressor, and you can buy a new Denso.

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