Air conditioning compressor oil

I don't have an answer but would be interesting in knowing if anyone actually changes there refrigerant and filter?
Alan

 

My A/C was blowing kinda warm. At my last service they topped off the refrigerant as it was quite a few PSI below full.

 

...you can't "check" the level and unless your system has a leak, there is no need to add oil.

 

You can't. The oil is suspended and flows through the entire system.

Scott

 

What is the part number for the AC filter?

 

I agree. "Checking the oil level" makes no sense since the typical way of doing this (for an automotive A/C system) with a rotary compressor is to add a prescribed amount of oil to a clean system when starting from scratch.

Here are a few hints. The "filter" in the above photos is actually a "receiver-filter-dryer". It's job is explained in the name. It acts as a reservoir for refrigerant, it filters out debris, and it absorbs moisture.

Here's why: The A/C cycle starts when gas is compressed and sent to (usually) an air type radiator ( a condenser usually located near the engine radiator) to reject much of the heat acquired when a gas is compressed. Because the refrigerant is very carefully formulated for the system in question, this cooling of the hot, high pressure gas results in it condensing into a warm liquid.

Next it goes to the expansion valve where the warm liquid is expanded back to a gas by passing through a tiny orifice, usually equipped with an automatic throttling device. If this tiny opening is clogged with a piece of dirt or if water in the system freezes there, your A/C won't work. That's why you need a filter and a dryer.

There is a significant drop in temperature when the liquid expands to a gas as anyone who has used a hand held butane torch knows. This cold gas flows through another radiator (the evaporator) located inside the passenger compartment where a fan blows cool air onto the occupants. From there, the now warmer gas returns to the compressor. That's it. You have passed Air Conditioning 101.

Because the compressor is driven by a shaft, it has a seal separating the high pressure refrigerant from the atmosphere. This rotating shaft seal will always leak a tiny bit which is why you need your system checked and topped off every 4 or 5 years. Letting the shaft sit in one position harms this seal, so you should run your A/C for a few minutes every month. Of course, Ferrari owners typically violate this rule, but do your best; i.e. when you do drive your Ferrari, don't forget to turn on the A/C even if it's cold outside.

Your home refrigerator, by contrast, has everything (including the electric motor) sealed in a can, so it doesn't typically leak and might run for 50 years with a little luck.

I would argue against changing the receiver/filter/dryer on a regular basis if the A/C is working. When it no longer cools correctly, find any A/C technician (he/she need not be a Ferrari mechanic) and attach a set of gauges so he/she can check your system. If there isn't a leak other than the normal small leakage associated with the shaft seal, perhaps the addition of a little refrigerant is all you need. But whenever you open the system, be sure to change the receiver/filter/dryer, evacuate the system to remove any moisture, and then recharge with the proper amount of refrigerant (usually done by weight)

By the way, these receiver/filter/dryers come in many sizes. Many have a sight glass built into the top but not all. As long as the fittings are an exact match for your car then any receiver/filter/dryer near the correct size will be fine although since they're usually connected with rigid tubing, you'll have to find one with the correct orientation with the inlet and outlet in the proper position because you might not have much ability to move the connecting tubing. This varies from car-to-car. Consult with your A/C technician and/or a smart auto parts store counter clerk.

 

All due respect, what you are showing is not an A/C filter but the receiver drier with the trinary switch. The receiver is like an accumulator that has a diseccant cartridge. They do not need to be replaced every two years, only when the system is serviced (b/c of leaks) since moisture may saturate the diseccant (45 mins in the oven can help if it is inobtanium). Trinary switch is a safeguard for the compressor which prevents the system from running below a certain pressure. BTW, the compressor can be rebuilt for less than $300, and most pipes and parts can be had at a fraction of the factory prices (A/C systems are as basic as a two stroke engine).

 

Thanks! Car is in for service and I'm having them change the part out. Learn all kinds of interesting things on FerrariChat. Maybe makes me slightly more OCD than is required learning of all these maintenance items, but it feels good.