Changed out the filter last night also. Yes it got dirty over the last year or two. Not as bad as when I first did it after about 4 years because my future wife at the time did not know the car had one. Still running Dexcol because I knew I could not get all of it out of the block. Shocked how bad the heat core was because what came out of radiator was not bad. After taking off the hoses I looked at the block and it looked clean.