Stop leak and oil coolers

[pushbroom]

Having heard about coolant stop leak blocking off passages in heater cores or oil coolers I finally actually came across one myself. Truck has an ISX motor and was having high oil temperature complaints. A new oil cooler element and t-stat were installed. The truck ran one trip and devolved a rad leak. Driver put a jug or 2 of stop leak into the system and finished out the trip. The following trip high oil temp was again observed. Brought the unit into the shop and pulled off the oil cooler element to discover most of the cooler was blocked off with the stop leak. Was able to clean the cooler out with a pressure washer and reuse it.
Sometimes rad stop leak can get you out of a tow bill, however this time it actually created more issues.

The side of the element in the picture is exposed to coolant, oil runs internally in the plates.