Yes this is a coolant filter I have on my 99 grand marquis that had a neglected cooling system. The coolant stays clean now but the filter keeps catching debris. I flushed that system 3 different times and put all new hoses on, with a new expansion tank and stuff is still floating around in the system. I flushed the block and radiator with all hoses off for 30 minutes the last time which is when I installed the coolant filter. I'm glad the engine oil side is spotless at least.