The appearance of white powder below the air conditioning lines in the engine compartment may be noticeable on some 2017-2018 Colorado and Canyon models. (Fig. 8)
Fig. 8
The powder substance is not corrosion. It is most likely caused by flux build-up on the A/C line during the supplier brazing process. (Fig. 09)
Verify that there are not any leaks on the A/C line and clean the flux build-up using a soft wire brush.
Do not replace the A/C lines for this condition. It is a cosmetic condition only.
Fig. 9
– Thanks to Charles Hensley
