Air Conditioning System Flush Interval? 20+ Year Old System

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Jan 29, 2012
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I just realized my Toyota 4Runner is 22 years old now and the A/C system is all original, still blows cold. I'm wondering do A/C systems need to be periodically flushed and recharged? After all, it is a pump circulating fluid of which I would imagine there to be wear metals and such in there. Never really seen this discussed much. What do you guys think?
 
When something fails, service it, including all the o rings you can, receiver dryer, etc. until then, leave it alone unless performance degrades. If it does, evacuate and fill by mass... but if it’s leaking, you’re obliged to find and resolve the leak...
 
If it ain’t broke, don’t fix it. Resist the temptation to use those “all-in-one” refrigerants as well. The best thing you can do for HVAC system life is to run the AC compressor at least once a week.

The only compressors that don’t circulate oil throughout the system are the Denso ES electric scroll compressors used in many Toyota xEVs and Teslas. Those have an oil separator.
 
I'm also in the 'if it ain't broke don't touch it' camp. We have a 1993 Crown vic still running on its original charge of R-12 and blowing cold. System has never been opened..

Even hooking up gauges to the old valve stems to check it is asking for a leak at this point.
 
I just realized my Toyota 4Runner is 22 years old now and the A/C system is all original, still blows cold. I'm wondering do A/C systems need to be periodically flushed and recharged? After all, it is a pump circulating fluid of which I would imagine there to be wear metals and such in there. Never really seen this discussed much. What do you guys think?

The issue now is the system is probably filled with refrigerant that is no longer manufactured. Leave it alone unless there is an issue.
 
Curious as to what makes the A/C system different than any other mechanical system such that it's maintenance free? I would've thought any mention of lifetime fill fluids to be heresy around here.

I know the refrigerant should be good as long as it hasn't leaked out, but what about the lubricating oil? I would also think that over time the mixture may absorb moisture.
 
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I've had more A/C service/repair required on my vehicles than about anything else. After saying that, I'm the 3rd owner, since 1995, of a '66 Riviera. That car does now finally show a few bubbles in the sight glass, but almost blows as icy cold as it ever has and the connecting underhood tubing showing bright white frost. I've never touched the system and the 2nd owner said the same-you just never know sometimes!
 
I've had more A/C service/repair required on my vehicles than about anything else. After saying that, I'm the 3rd owner, since 1995, of a '66 Riviera. That car does now finally show a few bubbles in the sight glass, but almost blows as icy cold as it ever has and the connecting underhood tubing showing bright white frost. I've never touched the system and the 2nd owner said the same-you just never know sometimes!

The A/C is a sealed system. If any refrigerant leaks out then there is a leak that should be fixed. You don't do any maint on the refrigerant part of your refrigerator except maybe to clean dust or dog fur from the coils with a vacuum.
 
The issue now is the system is probably filled with refrigerant that is no longer manufactured. Leave it alone unless there is an issue.
Toyota switched over to R-134a in 1993 on the Lexus lineup, and it was complete by 1995 for the rest of their line. If that 4Runner was built after 1995, it uses R-134a and ND-Oil 6 PAG oil.
 
I was thinking it was before R134a.

Even if it was before 134, R-12 is very common, and available. It’s price has dropped as the demand has reduced, thouh finding capable shops is a bit more of a challenge...
 
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