HELP! AC question.. 1979 toyota

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The Radney's - 27 Sep 2003 15:24 GMT

I have a 1979 Toyota Pickup (20R). The AC system has been converted
to 134 and works OK... but only OK. When the compressor is on, it
blows very cool. But the problem is that the compressor FREQUENTLY
cycles in and out. I tried adding additional freon, but it doesn't
seem to help. Anybody have any ideas?

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chuck - 27 Sep 2003 17:51 GMT

> I have a 1979 Toyota Pickup (20R). The AC system has been converted
> to 134 and works OK... but only OK. When the compressor is on, it
> blows very cool. But the problem is that the compressor FREQUENTLY
> cycles in and out. I tried adding additional freon, but it doesn't
> seem to help. Anybody have any ideas?

Since it's so old it wouldn't hurt to try cleaning the coils. A clogged
evaporator can make it seem low on refrigerant. I'm not a big fan of
134A. The R12 works better, and easier assuming you have access to the R12.

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TOM - 27 Sep 2003 17:43 GMT

>>I have a 1979 Toyota Pickup (20R). The AC system has been converted
>>to 134 and works OK... but only OK. When the compressor is on, it
[quoted text clipped - 5 lines]
> evaporator can make it seem low on refrigerant. I'm not a big fan of
> 134A. The R12 works better, and easier assuming you have access to the R12.

That's true in most cases, but if your vehicle has been converted to use
the newer 134A, don't switch back to the more expensive R12. Equally
importantg, if your system is still using R12, don't simply switch to
134A, there are several things that need to be changed first...

This looks like a good place to look:
http://www.autocool-refrigerants.com/

Tom - Vista, CA

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Ken Shelton - 27 Sep 2003 19:17 GMT

R134a works well, but is less efficient than R12. This means that for
systems with equal output, the R134a system would require a larger
compressor, larger condenser, consume more hp, etc. When R134a is put into
a system with R12 hardware, it can't refrigerate as well.

Too much refrigerant in a system will fill the condenser, prevent adequate
cooling of the hot gas, and cause shutdowns on high head pressure. Too
little will cause low return pressure and shutdowns on low suction pressure.

As said, clean up what you've got, then get an expert to get your system
running as good as it can.

Ken

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