It's low on freon.
16.2 bar = 1,620 kPa
Your pressure gauge may be broken....If it fluctuates, then you know its not your gauge, but if your gauge always reads 80, it may need to be replaced.
Reverse airflow feels a chamber inside the gauge and reads the pressure equal to the inside of the tyre its that simple. Same for air compressure, when the pressure is applied it seals the valve on the gauge end then back pressure fills the chamber inside the gauge when you release the gauge from the tyre valve the pressure has gone!!
A manometer is a pressure gauge, "Manometer" reads extremely low pressures that are very close to atmospheric pressures, "pressure gauges" read much larger pressures.
It means the filter needs replacement
It is an electrical devise that "measures" the oil pressure and converts it into an electrical signal that a computer or the gauge cluster reads.
probably need a new compressor. definitely has a leak.
Yes. That is most likely a sensor malfunction and will do no harm. Zero pressure is when you worry.
GM oil pressure senders have a pretty high failure rate. Since your van is 10 years old, and pressure senders are not too expensive, I would start by replacing your sender...there's a pretty high likelihood that you will eventually replace it anyway.
that is too low of pressure.
Need to hook up a oil pressure gauge in the place were the oil sending unit is on the engine and see what the gauge reads, You should have no less then 20 LBS. at a idle. If it does not have oil pressure then pump is bad.
You might plan to refuel when your fuel gauge reads one-eighth of a tank of gasoline. Some people choose to refuel when the gauge reads one-quarter of a tank remaining.