Low Cooling AC

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kapilamuni
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Low Cooling AC

Postby kapilamuni » Sun May 19, 2019 12:39 am

Hi all,

Recently changed my car's AC compressor clutch bearing. All went week & afterwards cooling was perfect for only 3 days.
Now the cooling has reduced to a very low level.

Here are my observations;
Outside temp = 32 C
When idling @ 750 RPM low = 75 PSI HIGH = 170 PSI, Interior temp = 27 C
1500 RPM LOW = 55 HIGH = 180 Interior temp = 26 C
2000 rpm low = 45 high = 200 Int temp = 25.5 C

With a card board inserted in front of AC fans, to cover air flow

2000 RPM LOW = 45 HIGH = 210 Int temp 24 C

Your advise appreciated.
Last edited by kapilamuni on Sun May 19, 2019 12:53 am, edited 1 time in total.
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kapilamuni
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Re: Low Cooling AC

Postby kapilamuni » Sun May 19, 2019 12:52 am

Oops. Forgot add.
My car is BMW 525TDS with ND 10PA17 compressor.

Also, noted that with AC off, after about few minutes LOW = 120 PSI & HIGH = 120 PSI.
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Tim
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Re: Low Cooling AC

Postby Tim » Sun May 19, 2019 6:28 pm

What year?
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kapilamuni
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Re: Low Cooling AC

Postby kapilamuni » Fri May 24, 2019 6:52 pm

It's 1996 june.
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Tim
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Re: Low Cooling AC

Postby Tim » Sat May 25, 2019 3:08 pm

No listing in the US for that vehicle. If an expansion valve system. Your low side pressures are high.
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kapilamuni
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Re: Low Cooling AC

Postby kapilamuni » Sat May 25, 2019 7:53 pm

Yes, it's an expansion valve system. What could be the reason/s to have high low side / low high side pressures?
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Tim
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Re: Low Cooling AC

Postby Tim » Sun May 26, 2019 9:22 am

Is this an original R134a vehicle? Charge levels is a place to start. Possible restriction but unlucky. Normal expansion valve systems will have a low of around 12/18 at high RPM.
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kapilamuni
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Re: Low Cooling AC

Postby kapilamuni » Mon May 27, 2019 4:47 am

Yes it's original system came with the car.
Can it be the clutch not engaging properly? Before this issue, on & off the belt slipping screeches were heard but not continuously. But cooling was not affected. Now it's not making such noises & the belt is fairly new.
The ratio you mention, is it low/high pressures or temp/pressure ratio?
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Cusser
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Re: Low Cooling AC

Postby Cusser » Mon May 27, 2019 6:49 am

On some AC clutches, the gap becomes too large and and will not engage; can be reduced by removing a thin shim.
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kapilamuni
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Re: Low Cooling AC

Postby kapilamuni » Wed Jun 05, 2019 8:14 am

You are head-on.
Removed one of the shims and cooling back to normal.

Thanks.

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