87 4Runner

Information on some common auto air conditioning topics.
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Jsover
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87 4Runner

Post by Jsover »

Okay so here’s the story. So the guy that I got my 4Runner from said the ac worked it just had set and the refrigerant leaked out it’s 134 and the guy is trustworthy. I found the leak at the compressor housing of the original compressor. It was the original exspansion valve as well. I replaced the compressor filled with 134 all was good for 3-4 months. Something happened idk what but it stopped. Since then I’ve put on 2 compressors and I did an autozone expansion valve realized it was to different and ordered a denso one direct fit. Put it all on today held nitrogen pressure @300psi held vaccum no leaks. Started it up has about 24oz of 134 in it currently running about 10psi low side and 145 ish high side and no cold air..


Any help or ideas?
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JohnHere
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Re: 87 4Runner

Post by JohnHere »

Presuming the previous owner did the conversion properly from R-12 to R-134a (flushing, correct oil, etc.), it sounds undercharged to me at first glance—not a compressor problem—and it might now have too much oil in it. Did you add any oil to the system while changing the compressors, and what kind? Did each compressor come filled with oil? How much?

Your vehicle should have an under-hood decal that tells you what the refrigerant and oil capacities are. Is it still there and readable?

Lastly, testing for leaks with 300 PSI of nitrogen is too much pressure. The evaporator is a low-pressure device that can't tolerate more than about 100 PSI. The over-pressure of nitrogen might have blown-out the evaporator and caused a leak that it didn't have before.
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Jsover
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Re: 87 4Runner

Post by Jsover »

Yes compressor came with 3oz of oil pre filled for 134.

I did add a small bit of oil maybe half oz with dye to be able to see a leak if present. No leaks still holding same pressure of 88psi standing pressure. No blockages pressures equalize when turned off.
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JohnHere
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Re: 87 4Runner

Post by JohnHere »

If I understand correctly, each of the two replacement compressors came with 3 ounces of PAG oil pre-filled from the factory. According to my vague recollection (it's been a while), your 4Runner takes a total of about 7 ounces of oil—mineral oil originally, and PAG oil now.

Did you pour out and measure the PAG oil from the original (converted) compressor? How much oil was in it? Was it less than 3 ounces, the same, or was it more? If it was less or more than 3 ounces, then the amount in the first and second replacements would need to have been adjusted to compensate for the difference.

Is the under-hood decal still there to tell us how much refrigerant and oil it actually takes?
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