2004 F-150 Heritage AC

[Tim]

Doesn't matter where you add the dye/oil. It's all going to be mixed up in 10 seconds once you run the system.

More importantly, did you get all the flush out of the system? Any flushing agent left behind will break down your oil and cause a compressor failure.

[Cusser]

I would add that to the high side in other words, inlet side of the evaporator, correct?

Since there's currently no charge, I'd add to the most convenient place. Even if you are suspecting/checking for a leak in the evaporator.

[kenlou]

More importantly, did you get all the flush out of the system? Any flushing agent left behind will break down your oil and cause a compressor failure.

I blew air in the evaporator for 20 minutes off and on and got nothing but air out.

[JohnHere]

I agree with Tim. Adding dye to the TXV side or the suction side of the evaporator, I don't believe it makes any difference.