What Do These AC Pressure Readings Indicate? - PeachParts Mercedes-Benz Forum

oilslick · #1 03-31-2018, 08:50 AM

1987 300SDL

Ambient temp of 70*

System fully charged.

Engine at idle.

Minimal cooling detected.

Just trying to get the old gal ready for summertime.

R.Diesel · #2 03-31-2018, 09:30 AM

system not fully charged. What is your static reading (engine cold and off)?

leathermang · #3 03-31-2018, 09:30 AM

It is not as simple as having those two numbers available.
What exactly do you mean by ' fully charged' ?
How was that accomplished and or measured ?
What temperature is the air coming out of the center vent and what are the physical conditions extant ?
Have you read the thread in my signature on AC ?

oilslick · #4 03-31-2018, 11:03 AM

Jut shy of three cans of 134a.

leathermang · #5 03-31-2018, 11:10 AM

Did you flush and check for leaks before installing that 134a ?
Was the AC fully functioning at some time during your ownership of the car ?
Did it have 134a installed at the time you acquired the car ?
Did you put any oil into the system at the time you put the ' just shy of three cans' ?

Diseasel300 · #6 03-31-2018, 11:13 AM

That sure doesn't look charged to me. Just sitting there with the compressor shut off, I'd expect to see somewhere around 100PSI on both gauges just from standing pressure. Time to find the leak...

R.Diesel · #7 03-31-2018, 11:24 AM

First things first, check static pressure on cold engine and report back with numbers. We can discuss conjecture until the cows come home.

R.Diesel · #8 03-31-2018, 11:25 AM

Engine off ofc...