Air conditioning precharge....
 

longevity. Our 2001 Camry has never had a problem with good cool air in summer and has never needed to be precharged with freon(?) in its life. The same with our Boxsters in 2.5 years. What is it that makes some cars a/c so reliable and others not?
Can I expect the Camry's a/c to go another 12 years with no precharge required?
What causes a/c to diminish over time - leaky seals?

Should I be running the a/c in winter just a few minutes just to blow the cobwebs out?
Thanks in advance from you cool members!:)

Leaky seals are a big problem. Do run your A/C every mt. to keep the seals "wet".

Your compressor will run when you put the defrosters on pending outdoor temperatures.

Some systems seem to stay charged forever. A small leak on a small system = no cooling.

No top ups. Repair then evacuate and re charge.

I have never heard of a precharge. Is like like preheating an oven?

Do you mean re-charge?

My El Camino never leaked until the compressor blows up. After 324,000 miles I have been through three compressors. I use my AC a lot in Oklahoma.

My 911 does not leak anymore now that I have barrier hoses. If you run the defroster in cool mode you compressor will run in the winter. Running it some year round does seem to help. Not a problem around here.

Mobile ACs are now designed to never require a recharge but it depends on the car. My Subaru has an o-ring on the top of the compressor in the heat that dried out and leaked. The crimp on the rubber hose leaked on my Audi.

My vintage Porsche had hoses that were designed to leak a small amount. These are not used anymore.

Running the AC a few minutes every month is supposed to circulate the oil and lube the rubber seals. I not sure if this is really shown to be effective.

seal technology has gotten better.

The compressor OTOH....

While we are on seals... now that is is less than -15 deg F in Minnesota and the pressure inside the AC is less than outside do o-rings etc handle negative pressure?

I know the pressure switch will keep it from running (except in my Porsche where there isn't one).

Usually if they don't blow, they won't suck.

It is not always the case, one way or the other....

Leaks are the main reason an a/c system will begin to lose effectiveness. The most common being the schraeder valves, both high and low. Most are the same as a bicycle, and if you remember as a kid, you had to air up the tires every spring. The sealing/design of the valve core has gotten better though. However, owners often have them checked, and every time they do, the valve core wears out. If it works fine, never have it checked by the drop out at the lube place. They could introduce some contaminants into the system as well. It's just a bad idea.

Another reason the system becomes less efficient would be debris on the outside of the condenser. They get pretty filthy as they are the first thing to catch what's in the air or flies up from the roadway. To dissipate heat/transfer, you need good air flow through the condenser.

Fans are next, sometimes the fail, sometimes just one fails, but either way this will lead to high pressures in a situation where the car is moving at slow speeds.

On your Camry, you may just lose the a/c altogether a day after it worked perfectly. It's a common problem. The coil dies and the compressor will no longer engage. Depending on what I find on the clutch end of the business, I might just replace the coil, sometimes I replace the clutch assembly (includes the coil), sometimes the whole compressor. The latter is the only that requires a discharge of the system.