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Questions before my FIRST a/c job-I did my research!!

banditt007 on Tue July 10, 2012 11:55 PM User is offline

Year: 2002
Make: Toyota
Model: 4runner
Engine Size: 3.4
Refrigerant Type: r134a
Country of Origin: United States

I've done as much research as i can, and this weekend will be my FIRST time tackling an a/c job-replacing o rings that are leaking and valve cores/caps, and for good measuring installing a new dryer...a few questions remain and i hope you can please help me out....

-The under hood sticker lists a RANGE of recharge weight, how do i fine tune within that range? What am i specifically looking for? I don't know why i would choose a specific weight within that range...

-Once finished charging, i plan on disconnecting the high side from the truck, and shutting off r134a tank and opening both manifold wheels to allow the low side to "suck out" the accounted for r134a weight within the charging hoses and manifold (hope that made sense) will this negate the need to add additional 1.5-2oz per hose, of refrigerant?

-The Denso dryer i purchased says to add 20cc of oil to it-but the instructions seem to be a bit GENERIC, is there a 4runner specific amount?

Also the leaks in the system are from various o rings, with light oil leakage-i was going to add 1 more additional oz to compensate for this-what do you think? Unfortunately i do not have flushing equipment, and i know this is guessing but its the best i can do-i do have a graduated cylinder for measuring replacement oil.

-When vacuuming (system had charge when i bought it, but leaked, not sure if it was ever open to atmosphere) should i just start up the pump and run for 45min? 1 hour? I was planning on vacuuming for 45minutes, changing the oil in the pump, and letting it cool some, and then vacuuming an additional hour- i have the time.... How would you go about doing this?

-when checking for leaks under vacuum what is standard procedure? closing off the valves and waiting how long? and is any drop in vacuum too much, or is some acceptable?

O yeah, i also ordered Nylog blue-any precautions? i was just going to use it to lube up the o rings...

THanks very much, i really want this to be a success the first time.....

JJM on Wed July 11, 2012 12:37 AM User is offline

- I show 1.40 pounds of R-134a for this vehicle. If there's a range, go for the higher amount.

- I would "charge" the hoses first, measuring how much refrigerant they took, then charge the system. Takes the guesswork out of what's in the hoses.

- The add back for the dryer is generic, best you can do for a system that's not dry.

- Adding an extra ounce is probably a good idea. Of course, the only true way to ensure proper oil level is to flush and start with a dry system.

- If you have time, vacuum for a few hours, and preferable on a hot day. The lower the vacuum, the better, especially if you don't have a micron gauge.

- I like to wait at least 1/2 an hour, or even better yet 1 hour, to check for vacuum drop. That's typically good enough, though overnight is even better.

- Nylog is awesome.

I think you're going to do just fine, you're doing everything right.


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