96 850 A/C recharge. Do I need to add oil?

Post by **JimBee** » 22 Jul 2015, 10:50

That's basically the question: How do I know if additional oil is needed when adding R134?

Post by **jimmy57** » 22 Jul 2015, 11:25

Oil is needed when there is any reason to believe it has been lost. DO you know where it leaked?
Evap leaks usually will cause a small loss. The high side hose from compressor to condenser can lose oil with refrigerant loss.

Post by **misha** » 22 Jul 2015, 12:20

If you loose refrigerant,you will also loose oil.They go through the system as a mixture.
That said....if refrigeration is leaking,oil is leaking via the same spot.
When you servicing ac system....when charging system with r134a....oil is added through the same line.

Post by **JimBee** » 22 Jul 2015, 14:57

The system was charged a year ago using a machine at a repair shop. After that, cabin side air was plenty cold. Now it's cool at best, so I assume some refrigerant has been lost over the year.

The clutch might also need shimming since it goes to warm after about 15 minutes and I don't notice it cycling when that happens.

I'll measure the clutch clearance and adjust as necessary and then add some R134.

But I'm back to, how do I know how much oil to add?

Post by **JRL** » 22 Jul 2015, 15:22

If you think it's at least still half full, none is really necessary. If it's dry/empty then you always add it

Post by **Ozark Lee** » 22 Jul 2015, 15:48

The only time I ever add oil is when I either replace a component (VADIS and VIDA have a chart that lists the amount of oil to add for all of the major components) or if the system suffered a rupture that resulted in a rapid (nearly instantaneous) loss of refrigerant. If it just needs additional refrigerant you don't need to add oil at all.

...Lee

Post by **dosbricks** » 22 Jul 2015, 17:58

JRL wrote:If you think it's at least still half full, none is really necessary. If it's dry/empty then you always add it

The above is a more specific answer. But to quote from a recent thread I started:

" '98 S70 How much oil is necessary for the A/C compressor?
S70 A/C at 224k is all original except for the addition of the bread clip fix. I noticed the compressor to condenser hose is leaking some oil. This is the line that runs under the fan shroud and is the lowest component of the system. It has quite a bit of oil on it (the hose portion of the line only) which looks wet but is in fact rather thick, so indicative of a very slow leak. That would be true to the history of the system which has required only about 12oz. of refrigerant in 17 years. But I am concerned that the compressor might get low on oil. So does anyone know how many ounces of oil the system needs to operate safely?"

But to know when it's half full, one has to know how much the system contains, which would help in the judgement call.

Post by **abscate** » 22 Jul 2015, 19:33

A leak that slow won't carry oil out in significant qty. if you serviced the system, I would replace the receiver/dryer and add the Volvo recommended amount of PAG for that component only.

NOTE! There are no high/low pressure connections on the compressor. Thus is it only possible to check the operation of the low pressure switch (Pressostat). Connecting to the service valve....on my 1999 it's 90cc of a 200 C&C total PAG capacity..

Volvo info....

BF2 Vacuum pumping

CAUTION! Check and top up with fresh compressor oil as required according to BG. Oil in the air conditioning (A/C) system below before vacuum-pumping the climate control unit on the car.

Vacuum pump system for at least 50 minutes .

BF3 Amount of refrigerant in the air conditioning (A/C) system
Check the specification label on the right side spring strut turret in engine compartment to find out the air conditioning (A/C) system refrigerant capacity.

Fill the system via the service valve (according to BG2 ).

NOTE! Carry out a final leak test using a leak detector on the connections where new components have been installed.

BG. Oil in the air conditioning (A/C) System

Special tools: 981 1994-4

WARNING! OIL MUST NOT BE MIXED. ALWAYS USE THE CORRECT TYPE OF COMPRESSOR OIL.

NOTE! Too much lubricating oil will impair cooling. Too little oil will cause damage to the compressor.

BG1 Topping up lubricating oil

The oil must be topped up when repairing a leak or when replacing a component. The quantity required for the component in question will depend on whether leakage has taken place slowly or quickly.

Slow leakage (longer than 24 hours)
Normally with a slow leak there is little risk of oil loss. When installing new components the following procedures apply:
When replacing compressor: Drain and carefully measure the quantity of oil in the original condenser. Drain the oil from the new compressor and fill it with exactly the same amount of oil as drained from the original compressor (always at least 70 cubic cm (0.074 US qt.) ).
When replacing other components: Drain oil and measure quantity. Fill new component with same quantity of oil.
Rapid leakage (e.g. hose rupture)
Rapid leakage often means that lubricating oil escapes with the refrigerant.

When replacing component the oil quantities below apply to the new components:
Receiver/Drier 90 cubic cm
(0.095 US qt.)
Evaporator 50 cubic cm
(0.053 US qt.)
Compressor 200 cubic cm
(0.211 US qt.)
Condenser 20 cubic cm
(0.021 US qt.)
Hose 20 cubic cm
(0.021 US qt.)

Post by **JimBee** » 22 Jul 2015, 20:27

When replacing component the oil quantities below apply to the new components:
Receiver/Drier 90 cubic cm
(0.095 US qt.)
Evaporator 50 cubic cm
(0.053 US qt.)
Compressor 200 cubic cm
(0.211 US qt.)
Condenser 20 cubic cm
(0.021 US qt.)
Hose 20 cubic cm
(0.021 US qt.)

My receiver/dryer was replaced last summer. The shop used a machin that was set for the Q spec'd for the 850 to refill the system. I think they vacuumed the system then hooked up the machine.

According to the above table 3 oz. should have been added. But I have no way of knowing if it was or how much is in it now. I seem to recall they couldn't tell me either, just that once the machine is set for the specific car, it adds the proper amount.

From the discussion, there really isn't any way to know, short of starting over—correct? Even then, vacuuming the system doesn't remove all the existing oil, right?

Post by **Ozark Lee** » 22 Jul 2015, 21:25

JimBee wrote:Even then, vacuuming the system doesn't remove all the existing oil, right?

It removes very little. So little that you don't worry about it. Some of the recovery machines have a graduated cylinder that measures oil that comes out of the system but in practice it never accumulates enough to measure.

...Lee