I wanted to bump this thread and say that the r152a handles higher ambient temperatures so much better than R134a.

It was 118F today, and it was pulling 55F on the freeway, when last year in the same ambient, r134a was around 60F, so an improvement.

At idle, it jumped to 80F very quickly, but I am convinced at this point I am overcharged with oil. Once I fix some other issues, I plan to flush the entire system and put fresh oil in and see whether the pressures go down.

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