FlyVFR wrote:SuperK wrote:I would suggest also taking it to a shop and have them evacuate the remaining r12.
The oils in the R12, when mixed with R134, will congeal and lock up your compressor.
When I retrofitted my old truck, this is what happened. I thought I had it all out but there was still oil left.
That is why it's important to use the
R134 conversion kit. The oil in this kit will not react with any traces of the old R12 oil.

Some Smart Guy wrote:
I have seen conversion kits at some of the discount auto parts (Auto Zone, etc.) that have an oil that you meerly add to the system and it suppossedly changes the oil so it works, but none the seminars I have attended could recommend such an additive or even understand how it could work.
you can do it right, or you can do it... the "discount" way.
Purge the system of R12 and it's oil. It's the best way.