Automotive Air Conditioning Information Forum (Archives)

nyc951 on Thu August 05, 2010 9:25 AM

Year: 1998
Make: BMW
Model: 328i
Engine Size: 2.8
Refrigerant Type: 134a

Hi there,

My car uses PAG 100 according to the NAPA reference chart I found on this site. I want to add a couple of ounces of oil back into the a/c system, but I only have PAG 150 on hand. Will it be ok to mix the two viscosities since they are both PAG oils?

Thanks in advance.

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'98 328i

TRB on Thu August 05, 2010 9:31 AM

Best to not mix oils even if they are both a PAG. Will it hurt if you do?? Probably not. Could lower the life of the compressor.

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mk378 on Thu August 05, 2010 11:09 AM

Also PAG absorbs water readily, which destroys it's lubricating properties, so you should not use any from an old bottle that has been opened and sitting around for a while. Buy some fresh PAG 100.

nyc951 on Thu August 12, 2010 7:57 PM

Hi guys:

Today was ~85 degrees out with low humidity. The car was parked and I checked the pressures at 2000 RPM:

Low - ~30 to 33 psi
High - 300 to 320 psi

That High reading seems too high to me. What are your thoughts? When I started driving the car the vent temps got around 40 degrees, so it's working fine. Do I need to be concerned with the pressure readings?

Thank you

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'98 328i

nyc951 on Mon August 16, 2010 7:22 PM

Bump for responses to my question, please
I want to know if the high side pressure is too high and if I should have the system recovered and recharged.
Thanks2

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'98 328i

iceman2555 on Mon August 16, 2010 8:28 PM

At the stated RPM...the ambient temp...not sure about 'low' humidity....the pressures and temps are acceptable.

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