Radiator deposits
I am using custom radiator with my Rotax 914. Since it is without suffix 01, so I am using EVANS NPG PLUS. Its flight hours are around 2 hrs. Today when I opened pressure cap of radiator after 30 mins of flight I found white gray sludge in my radiator neck and on pressure cap as shown in picture in the attachment.
I don't know why and how it happened as I never found this type of material in cooling system of my old aircrafts and other aircrafts of flying club using rotax with waterless coolant.
Expert opinion is requested.
Regards
.